Sample records for tabaci lindeman thysanoptera

  1. Toxicity of selected insecticides to onion thrips (Thysanoptera: Thripidae) using a glass-vial bioassay

    USDA-ARS?s Scientific Manuscript database

    Onion thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae), are important pests that are primarily controlled with insecticides on both onions and cotton in the Lower Rio Grande Valley of Texas. Resistance to various insecticides has been reported so data are needed on toxicity of insecticides r...

  2. Effects of heat stress on survival of Frankliniella occidentalis (Thysanoptera: Thripidae) and Thrips tabaci (Thysanoptera: Thripidae).

    PubMed

    Wang, J C; Zhang, B; Wang, J P; Li, H G; Wang, S F; Sun, L J; Zheng, C Y

    2014-08-01

    Temperature is known to play a crucial role in the population dynamics of insects. Insects have evolved different mechanisms to resist unfavorable extreme temperatures. In recent years, western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), and onion thrips, Thrips tabaci (Lindeman) (Thysanoptera: Thripidae), have caused significant damage to vegetable crops. Because of global warming and expanding areas of vegetable cultivation, a study of the effects of heat stress on these thrips species is warranted. We exposed the various developmental stages of western flower thrips and onion thrips to temperatures of 41, 43, or 45 degrees C for 2, 6, 12, 24, or 36 h to determine the effects of heat stress on survival. Our results showed that the heat resistance of nonadult western flower thrips was greater than that of the nonadult onion thrips, and that the natural heat resistant ability was the primary factor in heat resistance in western flower thrips. In contrast, the heat resistance of adult onion thrips was greater than that of the adult western flower thrips, which was primarily the result of the ability of searching suitable microenvironment that enabled the onion thrips to mitigate the effects of high temperatures more efficiently than the western flower thrips. Our analysis of the differences in heat resistance between western flower thrips and onion thrips provides important information for the development of thermal treatments for controlling western flower thrips and onion thrips.

  3. Temporal dynamics of iris yellow spot virus and its vector, Thrips tabaci (Thysanoptera: Thripidae), in seeded and transplanted onion fields.

    PubMed

    Hsu, Cynthia L; Hoepting, Christine A; Fuchs, Marc; Shelton, Anthony M; Nault, Brian A

    2010-04-01

    Onion thrips, Thrips tabaci (Lindeman) (Thysanoptera: Thripidae), can reduce onion bulb yield and transmit iris yellow spot virus (IYSV) (Bunyaviridae: Tospovirus), which can cause additional yield losses. In New York, onions are planted using seeds and imported transplants. IYSV is not seed transmitted, but infected transplants have been found in other U.S. states. Transplants are also larger than seeded onions early in the season, and thrips, some of which may be viruliferous, may preferentially colonize larger plants. Limited information is available on the temporal dynamics of IYSV and its vector in onion fields. In 2007 and 2008, T. tabaci and IYSV levels were monitored in six seeded and six transplanted fields. We found significantly more thrips in transplanted fields early in the season, but by the end of the season seeded fields had higher levels of IYSV. The percentage of sample sites with IYSV-infected plants remained low (<12%) until August, when infection levels increased dramatically in some fields. The densities of adult and larval thrips in August and September were better predictors of final IYSV levels than early season thrips densities. For 2007 and 2008, the time onions were harvested may have been more important in determining IYSV levels than whether the onions were seeded or transplanted. Viruliferous thrips emigrating from harvested onion fields into nonharvested ones may be increasing the primary spread of IYSV in late-harvested onions. Managing T. tabaci populations before harvest, and manipulating the spatial arrangement of fields based on harvest date could mitigate the spread of IYSV.

  4. Impact of straw mulch on populations of onion thrips (Thysanoptera: Thripidae) in onion.

    PubMed

    Larentzaki, E; Plate, J; Nault, B A; Shelton, A M

    2008-08-01

    Development of insecticide resistance in onion thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae), populations in onion (Allium spp.) fields and the incidence of the T. tabaci transmitted Iris yellow spot virus have stimulated interest in evaluating alternative management tactics. Effects of straw mulch applied in commercial onion fields in muck areas of western New York were assessed in 2006 and 2007 as a possible onion thrips management strategy. In trials in which no insecticides were applied for thrips control, straw mulch-treated plots supported significantly lower T. tabaci populations compared with control plots. In both years, the action thresholds of one or three larvae per leaf were reached in straw mulch treatments between 7 and 14 d later than in the control. Ground predatory fauna, as evaluated by pitfall trapping, was not increased by straw mulch in 2006; however, populations of the common predatory thrips Aeolothrips fasciatus (L.) (Thysanoptera: Aeolothripidae) were significantly lower in straw mulch plots in both years. Interference of straw mulch in the pupation and emergence of T. tabaci was investigated in the lab and their emergence was reduced by 54% compared with bare soil. In the field the overall yield of onions was not affected by the straw mulch treatment; however, the presence of jumbo grade onions (>77 mm) was increased in 2006, but not in 2007. These results indicate that populations of T. tabaci adults and larvae can be significantly reduced by the use of straw mulch without compromising overall onion yield. The use of this cultural practice in an onion integrated pest management program seems promising.

  5. Onion thrips (Thrips tabaci (Thysanoptera: Thripidae)) in cabbage on Prince Edward Island: observations on planting date and variety choice.

    PubMed

    Blatt, Suzanne; Ryan, Andrew; Adams, Shelley; Driscoll, Joanne

    2015-01-01

    Onion thrips (Thrips tabaci Lindeman (Thysanoptera: Thripidae)) can be a pest in organic onion production on Prince Edward Island. This study was to examine the effect of planting time and variety on infestation levels and damage by onion thrips on cabbage (Brassicae oleracea capitala (L.)). A field site was planted with 2 main and 8 lesser varieties of cabbage over 4 planting dates. Some varieties were short season and harvested on July 31 with longer season varieties harvested on September 2. Blue sticky traps were used to capture thrips migrating into the field site from July 22-September 2. Traps were counted weekly and cabbage heads within the field site were visually surveyed for thrips. At harvest, heads were weighed and measured, thrips damage was assessed then the head was dissected and thrips counted on the first four layers of the head. Thrips exhibited a preference for Lennox over Bronco throughout the season although thrips populations were not high enough to effect economic damage in 2014. Planting date influenced cabbage head weight and size with later plantings yielding the largest heads. Use of planting date and variety to avoid thrips populations is discussed.

  6. Herbivory by Thrips tabaci

    Treesearch

    Deborah M. Kendall

    1991-01-01

    Herbivory by Thrips tabaci (Lindeman) affects both the bulb yield and phytohormone balance in its major host plant, the onion (Alium cepa L.). Seasonal changes in the susceptibility of onion yield to T. tabaci feeding were examined during the three growth stages of onion; prebulbing, bulbing and sizing (Kendall...

  7. Within-plant distribution of onion thrips (Thysanoptera: Thripidae) in onions.

    PubMed

    Mo, Jianhua; Munro, Scott; Boulton, Alan; Stevens, Mark

    2008-08-01

    Two aspects of the within-plant distribution of Thrips tabaci Lindeman (Thysanoptera: Thripidae) on onion, Allium cepa L., plants were investigated: 1) diurnal variations in the distribution of adults and larvae between basal and upper sections of onion leaves, and 2) between-leaf and within-leaf distribution of the eggs. The diurnal investigations showed that higher proportions of larvae than of adults congregated at the basal sections of plants, particularly when plants were young and thrips density was low. As plants matured and thrips density increased, the larvae became more dispersed. Regardless of plant size, there were always more adults in the upper than basal plant sections. There were no clear time-windows during the 24-h diurnal cycle when more thrips were in the upper plant parts. T. tabaci eggs were laid everywhere in the plant. Leaves of intermediate ages had more eggs than older or younger leaves. Within leaves, the white leaf sheath received the least eggs and leaf tips received slightly more eggs than leaf sheaths. The highest egg density was found between the green leaf base and the leaf tips. Regardless of plant size, more than half of all eggs were laid above the basal sections. The percentage increased to >95% in mature plants. Except when plants were small the outer leaves were preferred over inner leaves and upper leaf sections preferred over lower leaf sections as egg-laying sites by adults. Implications of the results in the management of T. tabaci are discussed.

  8. Evaluating an Action Threshold-Based Insecticide Program on Onion Cultivars Varying in Resistance to Onion Thrips (Thysanoptera: Thripidae).

    PubMed

    Nault, Brian A; Huseth, Anders S

    2016-08-01

    Onion thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae), is a highly destructive pest of onion, Allium cepa L., and its management relies on multiple applications of foliar insecticides. Development of insecticide resistance is common in T. tabaci populations, and new strategies are needed to relax existing levels of insecticide use, but still provide protection against T. tabaci without compromising marketable onion yield. An action threshold-based insecticide program combined with or without a thrips-resistant onion cultivar was investigated as an improved approach for managing T. tabaci infestations in commercial onion fields. Regardless of cultivar type, the average number of insecticide applications needed to manage T. tabaci infestations in the action-threshold based program was 4.3, while the average number of sprays in the standard weekly program was 7.2 (a 40% reduction). The mean percent reduction in numbers of applications following the action threshold treatment in the thrips-resistant onion cultivar, 'Advantage', was 46.7% (range 40-50%) compared with the standard program, whereas the percentage reduction in applications in action threshold treatments in the thrips-susceptible onion cultivar, 'Santana', was 34.3% (range 13-50%) compared with the standard program, suggesting a benefit of the thrips-resistant cultivar. Marketable bulb yields for both 'Advantage' and 'Santana' in the action threshold-based program were nearly identical to those in the standard program, indicating that commercially acceptable bulb yields will be generated with fewer insecticide sprays following an action threshold-based program, saving money, time and benefiting the environment. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  9. Consequences of co-applying insecticides and fungicides for managing Thrips tabaci (Thysanoptera: Thripidae) on onion.

    PubMed

    Nault, Brian A; Hsu, Cynthia L; Hoepting, Christine A

    2013-07-01

    Insecticides and fungicides are commonly co-applied in a tank mix to protect onions from onion thrips, Thrips tabaci Lindeman, and foliar pathogens. Co-applications reduce production costs, but past research shows that an insecticide's performance can be reduced when co-applied with a fungicide. An evaluation was made of the effects of co-applying spinetoram, abamectin and spirotetramat with commonly used fungicides, with and without the addition of a penetrating surfactant, on onion thrips control in onion fields. Co-applications of insecticides with chlorothalonil fungicides reduced thrips control by 25-48% compared with control levels provided by the insecticides alone in three of five trials. Inclusion of a penetrating surfactant at recommended rates with the insecticide and chlorothalonil fungicide did not consistently overcome this problem. Co-applications of insecticides with other fungicides did not interfere with thrips control. Co-applications of pesticides targeting multiple organisms should be examined closely to ensure that control of each organism is not compromised. To manage onion thrips in onion most effectively, insecticides should be applied with a penetrating surfactant, and should be applied separately from chlorothalonil fungicides. © 2012 Society of Chemical Industry.

  10. Within-Plant Distribution and Dynamics of Thrips Species (Thysanoptera: Thripidae) in Cotton.

    PubMed

    Reay-Jones, Francis P F; Greene, Jeremy K; Herbert, D Ames; Jacobson, Alana L; Kennedy, George G; Reisig, Dominic D; Roberts, Phillip M

    2017-08-01

    A 2-yr study in cotton (Gossypium hirsutum L.) was conducted to determine the abundance and species composition of thrips (Thysanoptera: Thripidae) on different plant parts throughout the season in Alabama, Georgia, North Carolina, South Carolina, and Virginia. Plant parts sampled included seedlings, terminals with two expanded leaves, leaves from the upper, middle, and lower sections of the canopy, white flowers, and medium-sized bolls. Adult thrips were significantly more abundant on seedlings and flowers in 2014, and on flowers followed by seedlings and leaves from the middle canopy in 2015. Immature thrips were significantly more abundant on seedlings, followed by flowers in 2014, and on seedlings followed by leaves from the lower canopy and flowers in 2015. Across locations and plant parts, thrips consisted of Frankliniella tritici (Fitch) (46.8%), Frankliniella fusca Hinds (23.5%), Frankliniella occidentalis (Pergande) (17.1%), Neohydatothrips variabilis (Beach) (7.4%), Thrips tabaci (Lindeman) (1.8%), and other species (3.4%). Frankliniella fusca represented 86.7% of all thrips on seedlings, while F. tritici was more abundant on terminals (51.6%), squares (57.5%), and flowers (75.1%). Across all leaf positions, F. fusca was the most abundant species (28.8%), followed by F. tritici (19.2%), N. variabilis (18.8%), F. occidentalis (12.9%), and T. tabaci (5.2%), as well as other species (15.0%). As neonicotinoid insecticides remain a primary tool to manage seedling infestations of F. fusca, our data indicate that mid- to late-season applications of neonicotinoid insecticides targeting other insect pests will intensify selection pressure for resistance on F. fusca, the primary pest of seedling cotton. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. Thysanoptera of Bulgaria

    PubMed Central

    Karadjova, Olia; Krumov, Vladimir

    2015-01-01

    Abstract The present checklist includes data on the species composition, geographic distribution and feeding preferences of thrips species in Bulgaria. In total, 155 species in 48 genera are listed. Of these, 125 species belong to suborder Terebrantia and include 103 species of 33 genera in family Thripidae, 14 species of two genera in Aeolothripidae, seven species of two genera in Melanthripidae and one species in Fauriellidae. In suborder Tubulifera, 30 species of 10 genera in the single family Phlaeothripidae are listed. Of the 155 Bulgarian thrips species, 87.7% are phytophagous, 4.5% are obligate predators, 5.8% are mycophagous and 1.9% are with unknown feeding preferences. Fourteen pest species are listed for Bulgaria, of which Frankliniella occidentalis, Thrips tabaci and Haplothrips tritici are of economic importance. The list provides detailed information on the horizontal and vertical distribution of Thysanoptera in 5 regions and 45 subregions of Bulgaria. The present paper also includes an evaluation of the biodiversity of Thysanoptera and the extent to which each region of the country has been studied. PMID:26019678

  12. Detection of Gene Flow from Sexual to Asexual Lineages in Thrips tabaci (Thysanoptera: Thripidae)

    PubMed Central

    Li, Xiao-Wei; Wang, Ping; Fail, Jozsef; Shelton, Anthony M.

    2015-01-01

    Populations of Thrips tabaci are known to have two sympatric but genetically isolated reproductive modes, arrhenotoky (sexual reproduction) and thelytoky (asexual reproduction). Herein, we report behavioral, ecological and genetic studies to determine whether there is gene flow between arrhenotokous and thelytokous T. tabaci. We did not detect significant preference by arrhenotokous males to mate with females of a particular reproductive mode, nor did we detect significant behavioral differences between arrhenotokous males mated with arrhenotokous or thelytokous females in their pre-copulation, copulation duration and mating frequency. Productive gene transfer resulting from the mating between the two modes was experimentally confirmed. Gene transfer from arrhenotokous T. tabaci to thelytokous T. tabaci was further validated by confirmation of the passage of the arrhenotokous male-originated nuclear gene (histone H3 gene) allele to the F2 generation. These behavioral, ecological and genetic studies confirmed gene transfer from the sexual arrhenotokous mode to the asexual thelytokous mode of T. tabaci in the laboratory. These results demonstrate that asexual T. tabaci populations may acquire genetic variability from sexual populations, which could offset the long-term disadvantage of asexual reproduction. PMID:26375283

  13. From Lindeman to Knowles: A Change in Vision.

    ERIC Educational Resources Information Center

    Fisher, James C.; Podeschi, Ronald L.

    1989-01-01

    Analyzes basic differences in the views of the purpose and process of adult education proposed by Eduard Lindeman and Malcolm Knowles. For Lindeman, adult education's purpose is changing the social order as well as improving individuals. Knowles focuses on preparing individuals for change, fulfilling individual needs while contributing to…

  14. Thrips (Thysanoptera: Thripidae, Phlaeothripidae) damaging peach in Paranapanema, São Paulo State, Brazil.

    PubMed

    Pinent, Silvia M J; Mascaro, Fernando; Botton, Marcos; Redaelli, Luiza R

    2008-01-01

    Seeking to identify thrips species associated to peach and the injuries they cause, plants of Aurora and Tropic Beauty cultivars were weekly monitored, from May to August of 2005, in Holambra II district, in Paranapanema, SP. Flowers and fruits from six plants per hectare were sampled by the hitting technique. Frankliniella occidentalis (Pergande), F. schultzei (Trybom), F. gardenia (Moulton), F. condei John, F. insularis (Franklin) and Thrips tabaci Lindeman, in Thripidae, and Haplothrips gowdeyi (Franklin), in Phlaeothripidae were identified. F. occidentalis was dominant, comprising 55.7% of the total specimens sampled. Slight and severe injuries were registered in fruits.

  15. Long-Distance Dispersal Potential for Onion Thrips (Thysanoptera: Thripidae) and Iris yellow spot virus (Bunyaviridae: Tospovirus) in an Onion Ecosystem.

    PubMed

    Smith, Erik A; Fuchs, M; Shields, E J; Nault, B A

    2015-08-01

    Onion thrips, Thrips tabaci Lindeman, is a worldwide pest of onion whose feeding damage and transmission of Iris yellow spot virus (IYSV) may reduce onion yields. Little is known about the seasonal dynamics of T. tabaci dispersal, the distance of dispersal, or the movement of thrips infected with IYSV during the onion-growing season. To address these questions, T. tabaci adults were collected using transparent sticky card traps in commercial onion fields three times during the onion-growing season (June, July, and late August) at varying heights above the canopy (0.5-6 m above soil surface) and with trap-equipped unmanned aircraft (UAVs) flying 50-60 m above onion fields during August sampling periods in 2012 and 2013. Randomly selected subsamples of captured T. tabaci were tested for IYSV using RT-PCR. Most T. tabaci adults were captured in late August and near the onion canopy (<2 m) throughout the season. However, 4% of T. tabaci adults captured on sticky cards were at altitudes ≥2 m, and T. tabaci were also captured on UAV-mounted traps. These data strongly suggest that long-distance dispersal occurs. More T. tabaci captured on sticky cards tested positive for IYSV in August (53.6%) than earlier in the season (2.3 to 21.5% in June and July, respectively), and 20 and 15% of T. tabaci captured on UAV-mounted traps tested positive for IYSV in 2012 and 2013, respectively. Our results indicate that T. tabaci adults, including viruliferous individuals, engage in long-distance dispersal late in the season and likely contribute to the spread of IYSV. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. Onion thrips, Thrips tabaci, have gut bacteria that are closely related to the symbionts of the western flower thrips, Frankliniella occidentalis.

    PubMed

    de Vries, Egbert J; van der Wurff, André W G; Jacobs, Gerrit; Breeuwer, Johannes A J

    2008-01-01

    It has been shown that many insects have Enterobacteriaceae bacteria in their gut system. The western flower thrips, Frankliniella occidentalis Pergande [Thysanoptera: Thripidae], has a symbiotic relation with Erwinia species gut bacteria. To determine if other Thripidae species have similar bacterial symbionts, the onion thrips, Thrips tabaci, was studied because, like F. occidentalis, it is phytophagous. Contrary to F. occidentalis, T. tabaci is endemic in Europe and biotypes have been described. Bacteria were isolated from the majority of populations and biotypes of T. tabaci examined. Bacteria were present in high numbers in most individuals of the populations studied. Like F. occidentalis, T. tabaci contained one type of bacterium that clearly outnumbered all other types present in the gut. This bacterium was identified as an Erwinia species, as was also the case for F. occidentalis. However, its biochemical characteristics and 16S rDNA sequence differed from the bacteria present in F. occidentalis.

  17. Onion Thrips, Thrips tabaci, Have Gut Bacteria That are Closely Related to the Symbionts of the Western Flower Thrips, Frankliniella occidentalis

    PubMed Central

    de Vries, Egbert J.; van der Wurff, André W. G.; Jacobs, Gerrit; Breeuwer, Johannes A. J.

    2008-01-01

    It has been shown that many insects have Enterobacteriaceae bacteria in their gut system. The western flower thrips, Frankliniella occidentalis Pergande [Thysanoptera: Thripidae], has a symbiotic relation with Erwinia species gut bacteria. To determine if other Thripidae species have similar bacterial symbionts, the onion thrips, Thrips tabaci, was studied because, like F. occidentalis, it is phytophagous. Contrary to F. occidentalis, T. tabaci is endemic in Europe and biotypes have been described. Bacteria were isolated from the majority of populations and biotypes of T. tabaci examined. Bacteria were present in high numbers in most individuals of the populations studied. Like F. occidentalis, T. tabaci contained one type of bacterium that clearly outnumbered all other types present in the gut. This bacterium was identified as an Erwinia species, as was also the case for F. occidentalis. However, its biochemical characteristics and 16S rDNA sequence differed from the bacteria present in F. occidentalis. PMID:20298113

  18. Molecular Identification of Thrips Species Infesting Cotton in the Southeastern United States.

    PubMed

    Wang, Hehe; Kennedy, George G; Reay-Jones, Francis P F; Reisig, Dominic D; Toews, Michael D; Roberts, Phillip M; Herbert, D Ames; Taylor, Sally; Jacobson, Alana L; Greene, Jeremy K

    2018-04-02

    Traditional identification of thrips species based on morphology is difficult, laborious, and especially challenging for immature thrips. To support monitoring and management efforts of thrips as consistent and widespread pests of cotton (Gossypium hirsutum L.), a probe-based quantitative PCR (qPCR) assay with crude DNA extraction was developed to allow efficient and specific identification of the primary species of thrips infesting cotton. The assay was applied to identify over 5,000 specimens of thrips (including 3,366 immatures) collected on cotton seedlings from Alabama, Georgia, North Carolina, South Carolina, and Virginia in 2016. One half of all adult samples were examined by morphological identification, which provided a statistically equivalent species composition as the qPCR method. Frankliniella fusca (Hinds) (Thysanoptera: Thripidae) was the dominant species across all the locations (76.8-94.3% of adults and 81.6-98.0% of immatures), followed by Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) in Georgia, North Carolina, and Virginia (4.6-19% of adults and 1.7-17.3% of immatures) or Frankliniella tritici (Fitch) (Thysanoptera: Thripidae) in South Carolina (10.8% of adults and 7.8% of immatures). Thrips tabaci (Lindeman) (Thysanoptera: Thripidae) and Neohydatothrips variabilis (Beach) (Thysanoptera: Thripidae) were occasionally found among adults but were rarely present among immature thrips. These five species of thrips represented 98.2-100% of samples collected across the Southeast. The qPCR assay was demonstrated to be a valuable tool for large-scale monitoring of species composition of thrips at different life stages in cotton. The tool will contribute to a better understanding of thrips population structure in cotton and could assist with development and application of improved management strategies.

  19. Colonization of onions by endophytic fungi and their impacts on the biology of Thrips tabaci.

    PubMed

    Muvea, Alexander M; Meyhöfer, Rainer; Subramanian, Sevgan; Poehling, Hans-Michael; Ekesi, Sunday; Maniania, Nguya K

    2014-01-01

    Endophytic fungi, which live within host plant tissues without causing any visible symptom of infection, are important mutualists that mediate plant-herbivore interactions. Thrips tabaci (Lindeman) is one of the key pests of onion, Allium cepa L., an economically important agricultural crop cultivated worldwide. However, information on endophyte colonization of onions, and their impacts on the biology of thrips feeding on them, is lacking. We tested the colonization of onion plants by selected fungal endophyte isolates using two inoculation methods. The effects of inoculated endophytes on T. tabaci infesting onion were also examined. Seven fungal endophytes used in our study were able to colonize onion plants either by the seed or seedling inoculation methods. Seed inoculation resulted in 1.47 times higher mean percentage post-inoculation recovery of all the endophytes tested as compared to seedling inoculation. Fewer thrips were observed on plants inoculated with Clonostachys rosea ICIPE 707, Trichoderma asperellum M2RT4, Trichoderma atroviride ICIPE 710, Trichoderma harzianum 709, Hypocrea lixii F3ST1 and Fusarium sp. ICIPE 712 isolates as compared to those inoculated with Fusarium sp. ICIPE 717 and the control treatments. Onion plants colonized by C. rosea ICIPE 707, T. asperellum M2RT4, T. atroviride ICIPE 710 and H. lixii F3ST1 had significantly lower feeding punctures as compared to the other treatments. Among the isolates tested, the lowest numbers of eggs were laid by T. tabaci on H. lixii F3ST1 and C. rosea ICIPE 707 inoculated plants. These results extend the knowledge on colonization of onions by fungal endophytes and their effects on Thrips tabaci.

  20. Colonization of Onions by Endophytic Fungi and Their Impacts on the Biology of Thrips tabaci

    PubMed Central

    Muvea, Alexander M.; Meyhöfer, Rainer; Subramanian, Sevgan; Poehling, Hans-Michael; Ekesi, Sunday; Maniania, Nguya K.

    2014-01-01

    Endophytic fungi, which live within host plant tissues without causing any visible symptom of infection, are important mutualists that mediate plant–herbivore interactions. Thrips tabaci (Lindeman) is one of the key pests of onion, Allium cepa L., an economically important agricultural crop cultivated worldwide. However, information on endophyte colonization of onions, and their impacts on the biology of thrips feeding on them, is lacking. We tested the colonization of onion plants by selected fungal endophyte isolates using two inoculation methods. The effects of inoculated endophytes on T. tabaci infesting onion were also examined. Seven fungal endophytes used in our study were able to colonize onion plants either by the seed or seedling inoculation methods. Seed inoculation resulted in 1.47 times higher mean percentage post-inoculation recovery of all the endophytes tested as compared to seedling inoculation. Fewer thrips were observed on plants inoculated with Clonostachys rosea ICIPE 707, Trichoderma asperellum M2RT4, Trichoderma atroviride ICIPE 710, Trichoderma harzianum 709, Hypocrea lixii F3ST1 and Fusarium sp. ICIPE 712 isolates as compared to those inoculated with Fusarium sp. ICIPE 717 and the control treatments. Onion plants colonized by C. rosea ICIPE 707, T. asperellum M2RT4, T. atroviride ICIPE 710 and H. lixii F3ST1 had significantly lower feeding punctures as compared to the other treatments. Among the isolates tested, the lowest numbers of eggs were laid by T. tabaci on H. lixii F3ST1 and C. rosea ICIPE 707 inoculated plants. These results extend the knowledge on colonization of onions by fungal endophytes and their effects on Thrips tabaci. PMID:25254657

  1. Regional and temporal variation in susceptibility to lambda-cyhalothrin in onion thrips, Thrips tabaci (Thysanoptera: Thripidae), in onion fields in New York.

    PubMed

    Shelton, A M; Nault, B A; Plate, J; Zhao, J Z

    2003-12-01

    Populations of onion thrips, Thrips tabaci Lindeman, from commercial onion fields in New York were evaluated for their susceptibility to the commonly used pyrethroid, lambda-cyhalothrin (Warrior T), using a novel system called the Thrips Insecticide Bioassay System (TIBS). To use TIBS, thrips are collected directly from the plant into an insecticide-treated 0.5-ml microcentrifuge tube that has a flexible plastic cap with a small well into which 0.08 ml of a 10% sugar-water solution with food colorant is deposited. The solution is sealed into the well with a small piece of stretched parafilm through which the thrips can feed on the solution. Thrips mortality is assessed after 24 h with the help of a dissecting stereoscope. In 2001, onion thrips populations were collected from 16 different sites and resistance ratios were >1,000 in five populations. Percent mortality at 100 ppm, a recommended field rate, varied from 9 to 100%, indicating high levels of variation in susceptibility. Particular instances of resistance appeared to be the result of practices within an individual field rather than a regional phenomenon. In 2002, we also observed large differences in onion thrips susceptibility, not only between individual fields but also between thrips collected in a single field at mid season and late season, again suggesting that insecticide-use practices within an individual field caused differences in susceptibility. Additional tests indicated no differences in susceptibility between adult and larval onion thrips populations and only relatively minor differences between populations collected from different parts of the same field. Using TIBS, several populations of onion thrips with different susceptibilities to lambda-cyhalothrin were identified and then subjected to lambda-cyhalothrin-treated onion plants. There was a highly significant positive relationship between percent mortality of thrips from TIBS and percent mortality from the treated onion plants, indicating

  2. Towards understanding thysanoptera

    Treesearch

    Bruce L. Parker; Margaret Skinner; eds.

    1991-01-01

    Thirty-one papers and three posters on the systematics, biology, behavior and management of Thysanoptera, with particular reference to Taeniothrips inconsequens (Uzel), pear thrips, presented at an international conference in Burlington, Vermont.

  3. Thrips tabaci (Thysanoptera: Thripidae) and Iris yellow spot virus associated with onion transplants, onion volunteers, and weeds in Colorado

    USDA-ARS?s Scientific Manuscript database

    Thrips tabaci infestation was determined on onion transplants received in Colorado during March and April from out of state sources (Imperial Valley, near Phoenix Arizona, and southern Texas) during 2004 to 2008. In the five years of the study, 50% to 100% of the transplant lots sampled were found ...

  4. Thysanoptera-Terebrantia of the Hawaiian Islands: an identification manual

    PubMed Central

    Mound, Laurence; Nakahara, Sueo; Tsuda, Dick M.

    2016-01-01

    Abstract An illustrated identification system is presented to 99 species and 49 genera in three families recorded from the Hawaiian Islands in the Thysanoptera suborder Terebrantia. Only seven (possibly eight) of these species are considered endemic, the remainder being adventive to these islands. The only previous study of Hawaiian Thysanoptera, by Zimmerman in 1948, included 47 Terebrantia species in 21 genera. PMID:26843832

  5. Onion Thrips (Thysanoptera: Thripidae) Feeding Promotes Infection By Pantoea ananatis in Onion.

    PubMed

    Grode, Ari; Chen, Shicheng; Walker, Edward D; Szendrei, Zsofia

    2017-12-05

    Onion thrips, Thrips tabaci Lindeman, is a primary insect pest of onions (Allium cepa) worldwide. Onion thrips cause feeding damage by destroying epidermal tissue. They are also vectors of Pantoea ananatis (Serrano) Mergaert, the bacteria that causes center rot. Onions with center rot develop white streaks with water-soaked margins along the onion leaves, which turn necrotic and lead to bulb rot during storage. The role of thrips feeding on the establishment and progression of bacterial infection in onions has not been investigated. Onions infested with thrips and inoculated with P. ananatis had more necrotic tissue and symptoms were more severe with increasing thrips density. We conducted a fluorescence microscopy study that examined how P. ananatis (expressing a fluorescence protein gene) colonized a control group of onions without thrips in comparison to a test group of onions with thrips. We found that P. ananatis colonized some onions in the control group because of naturally existing wounds in the epidermal tissue but more colonization was found in the thrips infested group because of the increased presence of entry points caused by thrips feeding. Overall, our results demonstrate that wounds caused by thrips feeding facilitate center rot development by providing entry sites for the bacteria into leaf tissue. © The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  6. Thrips (Thysanoptera) of coffee flowers

    USDA-ARS?s Scientific Manuscript database

    A survey of thrips (Thysanoptera) associated with coffee flowers was conducted in coffee plantations in Chiapas, Mexico. The main objectives were to identify them and to determine whether they were carrying coffee pollen grains. A total of 40 thrips species in 22 genera were identified. The most com...

  7. Chemical ecology of the Thysanoptera

    Treesearch

    Murray S. Blum

    1991-01-01

    The chemical ecology of the Thysanoptera is identified with a variety of natural products discharged in anal droplets during confrontations with adversaries. These exudates are fortified with defensive allomones that may function as repellents, contact irritants, or in some cases, fumigants. Thrips synthesize a large diversity of allomonal products that include...

  8. Buprofezin inhibits acetylcholinesterase activity in B-biotype Bemisia tabaci.

    PubMed

    Cottage, Emma L A; Gunning, Robin V

    2006-01-01

    B-biotype Bemisia tabaci is a severe insect pest worldwide in many ornamental, agricultural, and horticultural industries. Control of this insect is hampered by resistance to many acetylcholinesterase (AChE)-inhibiting insecticides, such as organophosphates and carbamates. Consequently, insect growth regulators such as buprofezin, which act by inhibiting chitin synthesis, are being investigated for use against B-biotype B. tabaci in Australia. This study discusses the effects of buprofezin on B. tabaciAChE.

  9. Whitefly (Bemisia tabaci) management program for ornamental plants

    USDA-ARS?s Scientific Manuscript database

    Bemisia tabaci (Gennadius) commonly known as silverleaf whitefly, is a polyphagous pest considered to be one of the most notorious invasive arthropods worldwide. The pest status of Bemisia tabaci is complicated because of their well debated taxonomic architecture which was previously identified to c...

  10. Identification and characterization of doublesex in Bemisia tabaci.

    PubMed

    Guo, L; Xie, W; Liu, Y; Yang, Z; Yang, X; Xia, J; Wang, S; Wu, Q; Zhang, Y

    2018-04-16

    Bemisia tabaci (Gennadius) is an important agricultural pest with a worldwide distribution. Although B. tabaci is known to have a unique haplodiploid reproductive strategy, its sex determination mechanism is largely unknown. In this study, we cloned the full-length sequence of B. tabaci doublesex (Btdsx) and found that Btdsx has 28 splicing isoforms. We found two new splicing isoforms of transformer 2 (Bttra2), which encode two proteins. We also confirmed that both genes lack sex-specific splicing isoforms. Real-time quantitative PCR analysis showed that the expression of Btdsx and Bttra2 is higher in males than in females. RNA interference of Bttra2 affected the expression of Btdsx and vice versa. Furthermore, silencing of Bttra2 or Btdsx caused malformation of the male genitalia (anal style). It did not affect the female phenotype, but reduced the expression of vitellogenin gene in females. These results indicate that Btdsx is associated with sex determination in B. tabaci and that Btdsx and Bttra2 affect each other and are important for male genitalia formation. In addition to increasing our understanding of the roles of dsx and tra2 in the sex determination of B. tabaci, the results will be useful for studies of sex determination in other haplodiploid species. © 2018 The Royal Entomological Society.

  11. Ecological determinants of resistance to insecticides in Bemisia tabaci

    USDA-ARS?s Scientific Manuscript database

    Insecticide resistance is a critical issue in pest management and has often been implicated as the primary cause of outbreaks of the global whitefly pest Bemisia tabaci Gennadius. Resistance to all modes of action used commonly against B. tabaci has been documented in various locations throughout t...

  12. Identification of glutathione S-transferases in Bemisia tabaci (Hemiptera: Aleyrodidae) and evidence that GSTd7 helps explain the difference in insecticide susceptibility between B. tabaci Middle East-Minor Asia 1 and Mediterranean.

    PubMed

    He, C; Xie, W; Yang, X; Wang, S-L; Wu, Q-J; Zhang, Y-J

    2018-02-01

    The Bemisia tabaci (Gennadius) (Hemiptera:Aleyrodidae) species complex includes invasive and destructive pests of field crops, and the sibling species MEAM1 and MED are its two most damaging members. Previous research indicated that the replacement of Middle East-Minor Asia 1 (MEAM1) by Mediterranean (MED) as the dominant B. tabaci species in China can be mainly attributed to MED's greater tolerance to insecticides. Glutathione S-transferases (GSTs) play important roles in the detoxification of hydrophobic toxic compounds. To increase our understanding of differences in insecticide resistance between B. tabaci MEAM1 and MED, we searched the genomic and transcriptomic databases and identified 23 putative GSTs in both B. tabaci MEAM1 and MED. Through measuring mRNA levels of 18 of the GSTs after B. tabaci MEAM1 and MED adults were exposed to the insecticide imidacloprid, we found that the expression levels were increased more in B. tabaci MED than in MEAM1 (in particular, the expression level of GST-d7 was increased by 4.39-fold relative to the control). Knockdown of GST-d7 in B. tabaci MED but not in B. tabaci MEAM1 resulted in a substantial increase in the mortality of imidacloprid-treated adults. These results indicate that differences in GST-d7 may help explain why insecticide tolerance is greater in B. tabaci MED than in B. tabaci MEAM1. © 2017 The Royal Entomological Society.

  13. A Trichodorus (Triplonchida: Trichodoridae) nematode from thrips (Thysanoptera: Panchaetothripinae)

    USDA-ARS?s Scientific Manuscript database

    A thrips insect Caliothrips sp. (Thysanoptera: Panchaetothripinae) from persimmon fruit (Ebenaceae: Diospyros sp.) from an unknown origin, possibly Asia, was intercepted in a passenger bag in November 2012 at the Peace Arch Border Crossing from Surrey, British Columbia to Blaine, Washington by an AP...

  14. Systematics of Thysanoptera, pear thrips and other economic species

    Treesearch

    Sueo Nakahara

    1991-01-01

    The systematics of the Thysanoptera, and several economic species in the United States and Canada (North America) are discussed briefly. Morphological characters to distinguish the six families in North America and the following economic species, pear thrips (Taeniothrips inconsequens (Uzel)), basswood thrips (Thrips calcaratus...

  15. Characterization of a Newly Discovered Symbiont of the Whitefly Bemisia tabaci (Hemiptera: Aleyrodidae)

    PubMed Central

    Bing, Xiao-Li; Yang, Jiao; Zchori-Fein, Einat; Wang, Xiao-Wei

    2013-01-01

    Bemisia tabaci (Hemiptera: Aleyrodidae) is a species complex containing >28 cryptic species, some of which are important crop pests worldwide. Like many other sap-sucking insects, whiteflies harbor an obligatory symbiont, “Candidatus Portiera aleyrodidarum,” and a number of secondary symbionts. So far, six genera of secondary symbionts have been identified in B. tabaci. In this study, we report and describe the finding of an additional bacterium in the indigenous B. tabaci cryptic species China 1 (formerly known as B. tabaci biotype ZHJ3). Phylogenetic analysis based on the 16S rRNA and gltA genes showed that the bacterium belongs to the Alphaproteobacteria subdivision of the Proteobacteria and has a close relationship with human pathogens of the genus Orientia. Consequently, we temporarily named it Orientia-like organism (OLO). OLO was found in six of eight wild populations of B. tabaci China 1, with the infection rate ranging from 46.2% to 76.8%. Fluorescence in situ hybridization (FISH) of B. tabaci China 1 in nymphs and adults revealed that OLOs are confined to the bacteriome and co-occur with “Ca. Portiera aleyrodidarum.” The vertical transmission of OLO was demonstrated by detection of OLO at the anterior pole end of the oocytes through FISH. Quantitative PCR analysis of population dynamics suggested a complex interaction between “Ca. Portiera aleyrodidarum” and OLO. Based on these results, we propose “Candidatus Hemipteriphilus asiaticus” for the classification of this symbiont from B. tabaci. PMID:23144129

  16. Genome sequencing of the sweet potato whitefly Bemisia tabaci MED/Q

    USDA-ARS?s Scientific Manuscript database

    Crypic and invasive species of whitefly, Bemisia tabaci, are highly destructive agricultural and ornamental crop pest that as a group cause direct feeding damage to host plants and vector a large number of harmful plant viruses. Introductions of B. tabaci are difficult to quarantine and eradicate d...

  17. Investigating contact toxicity of Geranium and Artemisia essential oils on Bemisia tabaci Gen.

    PubMed

    Yarahmadi, Fatemeh; Rajabpour, Ali; Zandi Sohani, Nooshin; Ramezani, Leila

    2013-01-01

    Sweet potato whitefly, Bemisia tabaci Gen. (B. tabaci), is one of the most important pests of various greenhouse crops in Iran. Nowadays, chemical insecticides are broadly used for control of the pests that causes risk to consumer's health. For the first time, contact toxicity of Pelargonium roseum Andrews and Artemisia sieberi Besser essential oils on B. tabaci and its possible application against the whitefly was evaluated in 2012. Essential oil with concentrations of 2500, 1250, 125, and 12 ppm were used. Infested leaves of greenhouse cucumber were treated by mentioned concentrations. After 24 hours, mortality of B. tabaci was recorded and compared after correcting by Abbot's formula. RESULTS showed that all concentrations of the essential oil could significantly reduce population of B. tabaci compared with the control treatment. Phytotoxicity of the treated leaves were recorded after 24, 48, and 72 hours and compared with the control. Concentrations of 2500, 1250, and 125 ppm caused severe phytotoxicity on greenhouse cucumber leaves and therefore are not suitable for greenhouse application. Phytotoxicity of 12 ppm was relatively low. This data implicated suitable protective effects of the essential oils to the pest infestation. Therefore, essential oils distillated from Geranium and Artemisia could be applied to control B. tabaci in greenhouse cucumber at V/V 12 ppm.

  18. Investigating contact toxicity of Geranium and Artemisia essential oils on Bemisia tabaci Gen.

    PubMed Central

    Yarahmadi, Fatemeh; Rajabpour, Ali; Zandi Sohani, Nooshin; Ramezani, Leila

    2013-01-01

    Objective: Sweet potato whitefly, Bemisia tabaci Gen. (B. tabaci), is one of the most important pests of various greenhouse crops in Iran. Nowadays, chemical insecticides are broadly used for control of the pests that causes risk to consumer's health. For the first time, contact toxicity of Pelargonium roseum Andrews and Artemisia sieberi Besser essential oils on B. tabaci and its possible application against the whitefly was evaluated in 2012. Materials and Methods: Essential oil with concentrations of 2500, 1250, 125, and 12 ppm were used. Infested leaves of greenhouse cucumber were treated by mentioned concentrations. After 24 hours, mortality of B. tabaci was recorded and compared after correcting by Abbot's formula. Results: Results showed that all concentrations of the essential oil could significantly reduce population of B. tabaci compared with the control treatment. Phytotoxicity of the treated leaves were recorded after 24, 48, and 72 hours and compared with the control. Concentrations of 2500, 1250, and 125 ppm caused severe phytotoxicity on greenhouse cucumber leaves and therefore are not suitable for greenhouse application. Phytotoxicity of 12 ppm was relatively low. Conclusions: This data implicated suitable protective effects of the essential oils to the pest infestation. Therefore, essential oils distillated from Geranium and Artemisia could be applied to control B. tabaci in greenhouse cucumber at V/V 12 ppm. PMID:25050264

  19. High-level of resistance to spinosad, emamectin benzoate and carbosulfan in populations of Thrips tabaci collected in Israel.

    PubMed

    Lebedev, Galina; Abo-Moch, Fauzi; Gafni, Guy; Ben-Yakir, David; Ghanim, Murad

    2013-02-01

    The onion thrips, Thrips tabaci Lindeman, is a major pest of several crop plants in the genus Allium, such as onions, garlic and chives. In Israel, these crops are grown in open fields and in protected housing. This thrips is usually controlled by the application of chemical insecticides. In recent years, spinosad, emamectin benzoate and carbosulfan have been the major insecticides used for the control of the onion thrips. In the last 4 years, growers of chives and green onion from several regions of Israel have reported a significant decrease in the efficacy of insecticides used to control the onion thrips. The susceptibility of 14 populations of the onion thrips, collected mainly from chives between the years 2007 and 2011, to spinosad, emamectin benzoate and carbosulfan was tested using a laboratory bioassay. The majority of the populations showed significant levels of resistance to at least one of the insecticides. LC(50) values calculated for two of the studied populations showed that the resistance factor for spinosad compared with the susceptible population is 21 393, for carbosulfan 54 and for emamectin benzoate 36. Only two populations, collected from organic farms, were susceptible to the insecticides tested. This is the first report of a high resistance level to spinosad, the major insecticide used to control the onion thrips. Resistance cases to spinosad were associated with failures to control the pest. Populations resistant to spinosad also had partial or complete resistance to other insecticides used for controlling the onion thrips. Copyright © 2012 Society of Chemical Industry.

  20. Acylsucrose-Producing Tomato Plants Forces Bemisia tabaci to Shift Its Preferred Settling and Feeding Site

    PubMed Central

    Rodríguez-López, Maria Jose; Garzo, Elisa; Bonani, Jean Patrick; Fernández-Muñoz, Rafael; Moriones, Enrique; Fereres, Alberto

    2012-01-01

    Background The whitefly Bemisia tabaci (Genn.) causes dramatic damage to plants by transmitting yield-limiting virus diseases. Previous studies proved that the tomato breeding line ABL 14-8 was resistant to B. tabaci, the vector of tomato yellow leaf curl disease (TYLCD). This resistance is based on the presence of type IV glandular trichomes and acylsucrose production. These trichomes deter settling and probing of B. tabaci in ABL 14-8, which reduces primary and secondary spread of TYLCD. Methodology/Principal Findings Whitefly settlement preference was evaluated on the adaxial and abaxial leaf surfaces of nearly-isogenic tomato lines with and without B. tabaci-resistance traits, ‘ABL 14-8 and Moneymaker’ respectively, under non-choice and free-choice conditions. In addition, the Electrical Penetration Graph technique was used to study probing and feeding activities of B. tabaci on the adaxial and abaxial leaf surfaces of the same genotypes. B. tabaci preferred to settle on the abaxial than on the adaxial surface of ‘Moneymaker’ leaves, whereas no such preference was observed on ABL 14-8 tomato plants at the ten-leaf growth stage. Furthermore, B. tabaci preferred to feed on the abaxial than on the adaxial leaf surface of ‘Moneymarker’ susceptible tomato plants as shown by a higher number of sustained phloem feeding ingestion events and a shorter time to reach the phloem. However, B. tabaci standard probing and feeding behavior patterns were altered in ABL 14-8 plants and whiteflies were unable to feed from the phloem and spent more time in non-probing activities when exposed to the abaxial leaf surface. Conclusions/Significance The distorted behavior of B. tabaci on ABL 14-8 protects tomato plants from the transmission of phloem-restricted viruses such as Tomato yellow leaf curl virus (TYLCV), and forces whiteflies to feed on the adaxial side of leaves where they feed less efficiently and become more vulnerable to natural enemies. PMID:22427950

  1. Gynaikothrips uzeli (Thysanoptera: Phlaeothripidae) , New Record From Tartous, Syria

    PubMed Central

    Yaseen Ali, Ali

    2014-01-01

    Abstract The weeping fig thrips Gynaikothrips uzeli Zimmermann (Thysanoptera: Phlaeothripidae) is newly recorded for the first time in the leaf galls of the weeping fig tree Ficus benjamina L. (Rosales: Moraceae) in the coastal area of Tartous, Syria. The thrips caused purplish red spots on the leaf surface of the host plant and the leaves curl. G. uzeili appears to be successfully adapted to this area. PMID:25527584

  2. An introduction to the Thysanoptera a survey of the group

    Treesearch

    1991-01-01

    I acknowledge with gratitude the invitation of Bruce L. Parker, Margaret Skinner and the organizers of this meeting to open the proceedings. It is a great pleasure to be asked to enthuse about a group of insects for which I have long had a particular affection - the Thysanoptera. My problem is that relatively few of the world's entomologists - less than 0.2% -...

  3. Spatiotemporal Dynamics of Whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) in Commercial Watermelon Crops.

    PubMed

    Lima, Carlos H O; Sarmento, Renato A; Galdino, Tarcísio V S; Pereira, Poliana S; Silva, Joedna; Souza, Danival J; Dos Santos, Gil R; Costa, Thiago L; Picanço, Marcelo C

    2018-04-16

    Spatiotemporal dynamics studies of crop pests enable the determination of the colonization pattern and dispersion of these insects in the landscape. Geostatistics is an efficient tool for these studies: to determine the spatial distribution pattern of the pest in the crops and to make maps that represent this situation. Analysis of these maps across the development of plants can be used as a tool in precision agriculture programs. Watermelon, Citrullus lanatus (Thunb.) Matsum. and Nakai (Cucurbitales: Cucurbitaceae), is the second most consumed fruit in the world, and the whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is one of the most important pests of this crop. Thus, the objective of this work was to determine the spatiotemporal distribution of B. tabaci in commercial watermelon crops using geostatistics. For 2 yr, we monitored adult whitefly densities in eight watermelon crops in a tropical climate region. The location of the samples and other crops in the landscape was georeferenced. Experimental data were submitted to geostatistical analysis. The colonization of B. tabaci had two patterns. In the first, the colonization started at the outermost parts of the crop. In the second, the insects occupied the whole area of the crop since the beginning of cultivation. The maximum distance between sites of watermelon crops in which spatial dependence of B. tabaci densities was observed was 19.69 m. The adult B. tabaci densities in the eight watermelon fields were positively correlated with rainfall and relative humidity, whereas wind speed negatively affected whiteflies population.

  4. Estimating bacterial diversity in Scirtothrips dorsalis Hood (Thysanoptera: Thripidae) via next generation sequencing

    USDA-ARS?s Scientific Manuscript database

    The last two decades have produced a better understanding of insect-microbial associations and yielded some important opportunities for insect control. However, most of our knowledge comes from model systems. Thrips (Thysanoptera: Thripidae) have been understudied despite their global importance as ...

  5. The complete mitochondrial genome sequence of the western flower thrips Frankliniella occidentalis (Thysanoptera: Thripidae) contains triplicate putative control regions.

    PubMed

    Yan, Dankan; Tang, Yunxia; Xue, Xiaofeng; Wang, Minghua; Liu, Fengquan; Fan, Jiaqin

    2012-09-10

    To investigate the features of the control region (CR) and the gene rearrangement in the mitochondrial (mt) genome of Thysanoptera insects, we sequenced the whole mt genome of the western flower thrips Frankliniella occidentalis (Thysanoptera: Thripidae). The mt genome is a circular molecule with 14,889 nucleotides and an A+T content of 76.6%, and it has triplicate putative CRs. We propose that tandem duplication and deletion account for the evolution of the CR and the gene translocations. Intramitochondrial recombination is a plausible model for the gene inversions. We discuss the excessive duplicate CR sequences and the transcription of the rRNA genes, which are distant from one another and from the CR. Finally, we address the significance of the complicated mt genomes in Thysanoptera for the evolution of the CR and the gene arrangement of the mt genome. Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.

  6. Cryptic Species Identification and Composition of Bemisia tabaci (Hemiptera: Aleyrodidae) Complex in Henan Province, China

    PubMed Central

    Hu, Jian; Wang, Lun-Ji; Dong, Jun-Feng; Song, Yue-Qin; Sun, Hui-Zhong

    2017-01-01

    Abstract Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a cryptic species complex, causing significant crop losses in China during the last decade. Although knowledge of cryptic species composition and dynamics within B. tabaci complex is critical for developing sustainable pest management strategies, limited information is available on this pest in the Henan province of China. A systematic survey of the cryptic species composition and distribution of B. tabaci complex in different locations of Henan province was conducted in 2012. The results of RAPD-PCR and the gene for the mitochondrial cytochrome oxidase subunit-1 (mtCOI) based phylogenetic relationships established using Bayesian method indicated there were four known cryptic species MEAM1, MED, Asia II 3, Asia II 9 and a new cryptic species named China 6 in Henan province. In the survey, the invasive cryptic species MED and MEAM1 were found to be predominant with wide spread distribution across the surveyed regions. On the contrary, the indigenous B. tabaci cryptic species including Asia II 3, Asia II 9 and China 6 remained with low prevalence in some surveyed regions. Cryptic species MEAM1 and MED have not completely displaced the native B. tabaci in Henan province. This current study for the first time unifies our knowledge of the diversity and distribution of B. tabaci across Henan province of China. PMID:28973577

  7. Distribution of Bemisia tabaci (Hemiptera: Aleyrodidae) biotypes in Florida - Investigating the "Q" invasion

    USDA-ARS?s Scientific Manuscript database

    After the 2004 discovery of the Bemisia tabaci Q biotype in the U.S., there was an urgent need to determine its distribution. As part of a coordinated country-wide effort, an extensive survey of B. tabaci biotypes was conducted in Florida, with the cooperation of growers and state agencies, to moni...

  8. Cryptic Species Identification and Composition of Bemisia tabaci (Hemiptera: Aleyrodidae) Complex in Henan Province, China.

    PubMed

    Jiu, Min; Hu, Jian; Wang, Lun-Ji; Dong, Jun-Feng; Song, Yue-Qin; Sun, Hui-Zhong

    2017-05-01

    Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a cryptic species complex, causing significant crop losses in China during the last decade. Although knowledge of cryptic species composition and dynamics within B. tabaci complex is critical for developing sustainable pest management strategies, limited information is available on this pest in the Henan province of China. A systematic survey of the cryptic species composition and distribution of B. tabaci complex in different locations of Henan province was conducted in 2012. The results of RAPD-PCR and the gene for the mitochondrial cytochrome oxidase subunit-1 (mtCOI) based phylogenetic relationships established using Bayesian method indicated there were four known cryptic species MEAM1, MED, Asia II 3, Asia II 9 and a new cryptic species named China 6 in Henan province. In the survey, the invasive cryptic species MED and MEAM1 were found to be predominant with wide spread distribution across the surveyed regions. On the contrary, the indigenous B. tabaci cryptic species including Asia II 3, Asia II 9 and China 6 remained with low prevalence in some surveyed regions. Cryptic species MEAM1 and MED have not completely displaced the native B. tabaci in Henan province. This current study for the first time unifies our knowledge of the diversity and distribution of B. tabaci across Henan province of China. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America.

  9. Indigenous American species of the Bemisia tabaci complex are still widespread in the Americas.

    PubMed

    Barbosa, Leonardo da F; Marubayashi, Julio M; De Marchi, Bruno R; Yuki, Valdir A; Pavan, Marcelo A; Moriones, Enrique; Navas-Castillo, Jesús; Krause-Sakate, Renate

    2014-10-01

    Bemisia tabaci is a complex of at least 36 putative cryptic species. Since the late 1980s, the Middle East-Asia Minor 1 species (MEAM1, formerly known as the B biotype), has emerged in many tropical and subtropical regions of the world and in some areas has displaced the indigenous populations of B. tabaci. Based on analysis of the mtCOI gene, two indigenous species native to America have been reported: New World (NW, formerly the A biotype) and New World 2 (NW2). NW is present at least in Argentina, Brazil, Martinique, Mexico, Texas and Venezuela, and NW2 in Argentina, Bolivia and Brazil. Wild plants (Euphorbia sp. and Ipomoea sp.), as well as important crops such as tomato, bean and cotton, are still hosts for native B. tabaci populations in the Americas. MEAM1 has not completely displaced the native B. tabaci from the Americas. © 2014 Society of Chemical Industry.

  10. An overview of chilli thrips. Scirtothrips dorsalis (Thysanoptera: Thripidae) biology, distribution and management

    USDA-ARS?s Scientific Manuscript database

    In the insect order Thysanoptera, the genus Scirtothrips Shull contains more than 100 thrips species, among which 10 species have been reported as serious pests of agricultural crops. Within this genus, Scirtothrips dorsalis Hood is an emerging pest of various economically important host crops in th...

  11. Extensive survey of Bemisia tabaci (Hemiptera: Aleyrodidae) biotypes in Florida investigating the Q invasion

    USDA-ARS?s Scientific Manuscript database

    After the discovery of the Bemisia tabaci Q biotype in the U.S., there was an urgent need to determine its spread. As part of a coordinated whole country survey, an extensive survey of Bemisia tabaci biotypes was conducted in Florida through cooperation with growers and state agencies. This was done...

  12. Investigating the effect of invasion characteristics on onion thrips (Thysanoptera: Thripidae) populations in onions with a temperature-driven process model.

    PubMed

    Mo, Jianhua; Stevens, Mark; Liu, De Li; Herron, Grant

    2009-12-01

    A temperature-driven process model was developed to describe the seasonal patterns of populations of onion thrips, Thrips tabaci Lindeman, in onions. The model used daily cohorts (individuals of the same developmental stage and daily age) as the population unit. Stage transitions were modeled as a logistic function of accumulated degree-days to account for variability in development rate among individuals. Daily survival was modeled as a logistic function of daily mean temperature. Parameters for development, survival, and fecundity were estimated from published data. A single invasion event was used to initiate the population process, starting at 1-100 d after onion emergence (DAE) for 10-100 d at the daily rate of 0.001-0.9 adults/plant/d. The model was validated against five observed seasonal patterns of onion thrips populations from two unsprayed sites in the Riverina, New South Wales, Australia, during 2003-2006. Performance of the model was measured by a fit index based on the proportion of variations in observed data explained by the model (R (2)) and the differences in total thrips-days between observed and predicted populations. Satisfactory matching between simulated and observed seasonal patterns was obtained within the ranges of invasion parameters tested. Model best-fit was obtained at invasion starting dates of 6-98 DAE with a daily invasion rate of 0.002-0.2 adults/plant/d and an invasion duration of 30-100 d. Under the best-fit invasion scenarios, the model closely reproduced the observed seasonal patterns, explaining 73-95% of variability in adult and larval densities during population increase periods. The results showed that small invasions of adult thrips followed by a gradual population build-up of thrips within onion crops were sufficient to bring about the observed seasonal patterns of onion thrips populations in onion. Implications of the model on timing of chemical controls are discussed.

  13. Sensitivity of Bemisia Tabaci (Hemiptera: Aleyrodidae) to Several New Insecticides in China: Effects of Insecticide Type and Whitefly Species, Strain, and Stage

    PubMed Central

    Xie, Wen; Liu, Yang; Wang, Shaoli; Wu, Qingjun; Pan, Huipeng; Yang, Xin; Guo, Litao; Zhang, Youjun

    2014-01-01

    Abstract Whitefly biotypes B and Q are the two most damaging members of the Bemisia tabaci (Hemiptera: Aleyrodidae) species complex. Control of B. tabaci (and especially of Q) has been impaired by resistance to commonly used insecticides. To find new insecticides for B. tabaci management in China, we investigated the sensitivity of eggs, larvae, and adults of laboratory strains of B and Q (named Lab-B and Lab-Q) and field strains of Q to several insecticides. For eggs, larvae, and adults of B. tabaci and for six insecticides (cyantraniliprole, chlorantraniliprole, pyriproxyfen, buprofezin, acetamiprid, and thiamethoxam), LC 50 values were higher for Lab-Q than for Lab-B; avermectin LC 50 values, however, were low for adults of both Lab-Q and Lab-B. Based on the laboratory results, insecticides were selected to test against eggs, larvae, and adults of four field strains of B. tabaci Q. Although the field strains differed in their sensitivity to the insecticides, the eggs and larvae of all strains were highly sensitive to cyantraniliprole, and the adults of all strains were highly sensitive to avermectin. The eggs, larvae, and adults of B. tabaci Q were generally more resistant than those of B. tabaci B to the tested insecticides. B. tabaci Q eggs and larvae were sensitive to cyantraniliprole and pyriproxyfen, whereas B. tabaci Q adults were sensitive to avermectin. Field trials should be conducted with cyantraniliprole, pyriproxyfen, and avermectin for control of B. tabaci Q and B in China. PMID:25434040

  14. Lack of resistance development in Bemisia tabaci to Isaria fumosorosea after multiple generations of selection

    NASA Astrophysics Data System (ADS)

    Gao, Tianni; Wang, Zhaolei; Huang, Yü; Keyhani, Nemat O.; Huang, Zhen

    2017-02-01

    The emergence of insecticide resistant insect pests is of significant concern worldwide. The whitefly, Bemisia tabaci, is an important agricultural pest and has shown incredible resilience developing resistance to a number of chemical pesticides. Entomopathogenic fungi such as Isaria fumosorosea offer an attractive alternative to chemical pesticides for insect control, and this fungus has been shown to be an effective pathogen of B. tabaci. Little is known concerning the potential for the development of resistance to I. fumosorosea by B. tabaci. Five generations of successive survivors of B. tabaci infected by I. fumosorosea were assayed with I. fumosorosea. No significant differences in susceptibility to I. fumosorosea, number of ovarioles, or ovipostioning were seen between any of the generations tested. Effects of I. fumosorosea and cell-free ethyl acetate fractions derived from the fungus on the B. tabaci fat body, ovary, and vitellogenin were also investigated. These data revealed significant deformation and degradation of ovary tissues and associated vitellogenin by the fungal mycelium as well as by cell-free ethyl acetate fungal extracts. These data indicate the lack of the emergence of resistance to I. fumosorosea under the conditions tested and demonstrate invasion of the insect reproductive tissues during fungal infection.

  15. Sensitivity of Bemisia tabaci (Hemiptera: Aleyrodidae) to several new insecticides in China: effects of insecticide type and whitefly species, strain, and stage.

    PubMed

    Xie, Wen; Liu, Yang; Wang, Shaoli; Wu, Qingjun; Pan, Huipeng; Yang, Xin; Guo, Litao; Zhang, Youjun

    2014-01-01

    Whitefly biotypes B and Q are the two most damaging members of the Bemisia tabaci (Hemiptera: Aleyrodidae) species complex. Control of B. tabaci (and especially of Q) has been impaired by resistance to commonly used insecticides. To find new insecticides for B. tabaci management in China, we investigated the sensitivity of eggs, larvae, and adults of laboratory strains of B and Q (named Lab-B and Lab-Q) and field strains of Q to several insecticides. For eggs, larvae, and adults of B. tabaci and for six insecticides (cyantraniliprole, chlorantraniliprole, pyriproxyfen, buprofezin, acetamiprid, and thiamethoxam), LC50 values were higher for Lab-Q than for Lab-B; avermectin LC50 values, however, were low for adults of both Lab-Q and Lab-B. Based on the laboratory results, insecticides were selected to test against eggs, larvae, and adults of four field strains of B. tabaci Q. Although the field strains differed in their sensitivity to the insecticides, the eggs and larvae of all strains were highly sensitive to cyantraniliprole, and the adults of all strains were highly sensitive to avermectin. The eggs, larvae, and adults of B. tabaci Q were generally more resistant than those of B. tabaci B to the tested insecticides. B. tabaci Q eggs and larvae were sensitive to cyantraniliprole and pyriproxyfen, whereas B. tabaci Q adults were sensitive to avermectin. Field trials should be conducted with cyantraniliprole, pyriproxyfen, and avermectin for control of B. tabaci Q and B in China. © The Author 2014. Published by Oxford University Press on behalf of the Entomological Society of America.

  16. Effects of cucumber mosaic virus-infected chilli plants on non-vector Bemisia tabaci (Hemiptera: Aleyrodidae).

    PubMed

    Saad, Khalid A; Mohamad Roff, M N; Hallett, Rebecca H; ABd-Ghani, Idris B

    2017-06-08

    Plant virus infections are known to alter host plant attractiveness and suitability for insect herbivores. This study was conducted to determine how cucumber mosaic virus (CMV)-infected chilli plants affect the fitness and settling preferences of nonvector whitefly, Bemisia tabaci adults under dual-choice conditions with volatile organic compounds analyzed using solid phase microextraction coupled with gas chromatography-mass spectrometry (GC-MS). Results showed that the presence of CMV in chilli plants substantially affects the settling preferences of the B. tabaci, which preferred to settle on noninfected plants. Duration of the egg stage and the longevity and fecundity of adult B. tabaci on CMV-infected chilli plants were not markedly different from those on noninfected chilli plants. In contrast, the developmental time from egg to adult was significantly reduced in CMV-infected chilli plants compared to the noninfected plants. The results also showed that CMV-infected chilli plants released significantly more linalool and phenylacetaldehyde than noninfected plants. Overall, it was suggested that the behavioral response of B. tabaci might be modified by CMV-infected plants, which alter the release of specific headspace volatiles. Based on these results, the modification of plant volatile profiles may help in enhancing the effectiveness of biological control and the protection of crop plants against B. tabaci. © 2017 Institute of Zoology, Chinese Academy of Sciences.

  17. Baseline susceptibility of Bemisia tabaci B biotype (Hemiptera:Aleyrodidae) populations from Californis and Arizona to spirotetramat

    USDA-ARS?s Scientific Manuscript database

    Baseline toxicity levels to foliarly applied spirotetramat were established for 19 field populations of whiteflies, Bemisia tabaci B biotype from Arizona and California in 2008 and 2009. The susceptibility data was determined against the 2nd instar of B. tabaci field collections before the registrat...

  18. Compatibility of the entomopathogenic fungus Lecanicillium muscarium and insecticides for eradication of sweetpotato whitefly, Bemisia tabaci.

    PubMed

    Cuthbertson, Andrew G S; Walters, Keith F A; Deppe, Carola

    2005-08-01

    The compatibility of the entomopathogenic fungus Lecanicillium muscarium and chemical insecticides used to control the second instar stages of the sweetpotato whitefly, Bemisia tabaci, was investigated. The effect on spore germination of direct exposure for 24 h to the insecticides imidacloprid, buprofezin, teflubenzuron and nicotine was determined. Only exposure to buprofezin was followed by acceptable spore germination. However, all chemicals significantly reduced spore germination when compared to a water control. Infectivity of L. muscarium in the presence of dry residues of buprofezin, teflubenzuron and nicotine (imidacloprid is a systemic pesticide) on foliage were also investigated. No significant detrimental effects on the level of control of B. tabaci was recorded when compared with fungi applied to residue free foliage on either tomato or verbena plants. Fungi in combination with imidacloprid gave higher B. tabaci mortality on verbena foliage compared to either teflubenzuron or nicotine and fungi combinations. Use of these chemical insecticides with L. muscarium in integrated control programmes for B. tabaci is discussed.

  19. Cross-resistance relationships between neonicotinoids and pymetrozine in Bemisia tabaci (Hemiptera: Aleyrodidae).

    PubMed

    Gorman, Kevin; Slater, Russell; Blande, James D; Clarke, Alison; Wren, Jodie; McCaffery, Alan; Denholm, Ian

    2010-11-01

    Although cross-resistance between compounds in the same insecticide group is a frequently observed phenomenon, cross-resistance between groups that differ in structural and functional characteristics can be extremely unpredictable. In the case of controlling the whitefly, Bemisia tabaci Gennadius, neonicotinoids and the pyridine azomethine antifeedant pymetrozine represent independent lines of discovery that should be suited for alternation to avoid prolonged selection for the same resistance mechanism. Reports of an association between responses to neonicotinoids and pymetrozine were investigated by resistance profiling of seven B. tabaci strains and complementary reciprocal selection experiments. All strains demonstrated a consistent correlation between responses to three neonicotinoid compounds: thiamethoxam, imidacloprid and acetamiprid. Responses to neonicotinoids for six field strains clearly correlated with responses to pymetrozine. Reciprocal selection experiments confirmed an unexpected case of intergroup cross-resistance. A seventh strain exhibited a so far unique phenotype of strong resistance to pymetrozine but full susceptibility to neonicotinoids. Selection experiments confirmed that in this strain the mechanism of pymetrozine resistance is specific and has no implications for neonicotinoids. Cross-resistance between neonicotinoids and pymetrozine in B. tabaci probably reflects the overexpression of a cytochrome-P450-dependent monooxygenase capable of metabolising both types of compound in spite of their apparent structural dissimilarity. Given the predominance of this mechanism in B. tabaci, both can contribute to resistance management but should be placed within the same treatment 'window'. Copyright © 2010 Society of Chemical Industry.

  20. Pyrosequencing the Bemisia tabaci Transcriptome Reveals a Highly Diverse Bacterial Community and a Robust System for Insecticide Resistance

    PubMed Central

    Wu, Qing-jun; Wang, Shao-li; Yang, Xin; Yang, Ni-na; Li, Ru-mei; Jiao, Xiao-guo; Pan, Hui-peng; Liu, Bai-ming; Su, Qi; Xu, Bao-yun; Hu, Song-nian; Zhou, Xu-guo; Zhang, You-jun

    2012-01-01

    Background Bemisia tabaci (Gennadius) is a phloem-feeding insect poised to become one of the major insect pests in open field and greenhouse production systems throughout the world. The high level of resistance to insecticides is a main factor that hinders continued use of insecticides for suppression of B. tabaci. Despite its prevalence, little is known about B. tabaci at the genome level. To fill this gap, an invasive B. tabaci B biotype was subjected to pyrosequencing-based transcriptome analysis to identify genes and gene networks putatively involved in various physiological and toxicological processes. Methodology and Principal Findings Using Roche 454 pyrosequencing, 857,205 reads containing approximately 340 megabases were obtained from the B. tabaci transcriptome. De novo assembly generated 178,669 unigenes including 30,980 from insects, 17,881 from bacteria, and 129,808 from the nohit. A total of 50,835 (28.45%) unigenes showed similarity to the non-redundant database in GenBank with a cut-off E-value of 10–5. Among them, 40,611 unigenes were assigned to one or more GO terms and 6,917 unigenes were assigned to 288 known pathways. De novo metatranscriptome analysis revealed highly diverse bacterial symbionts in B. tabaci, and demonstrated the host-symbiont cooperation in amino acid production. In-depth transcriptome analysis indentified putative molecular markers, and genes potentially involved in insecticide resistance and nutrient digestion. The utility of this transcriptome was validated by a thiamethoxam resistance study, in which annotated cytochrome P450 genes were significantly overexpressed in the resistant B. tabaci in comparison to its susceptible counterparts. Conclusions This transcriptome/metatranscriptome analysis sheds light on the molecular understanding of symbiosis and insecticide resistance in an agriculturally important phloem-feeding insect pest, and lays the foundation for future functional genomics research of the B. tabaci complex

  1. Biology and Ecology of the Western Flower Thrips (Thysanoptera: Thripidae): The Making of a Pest

    USDA-ARS?s Scientific Manuscript database

    In the past 30 years, the western flower thrips Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) has become one of the most important agricultural pests worldwide. Certain biological attributes of this insect predispose it to be a direct pest across a wide range of crops. In additio...

  2. Transcriptomic and Proteomic Responses of Sweetpotato Whitefly, Bemisia tabaci, to Thiamethoxam

    PubMed Central

    Yang, Nina; Xie, Wen; Yang, Xin; Wang, Shaoli; Wu, Qingjun; Li, Rumei; Pan, Huipeng; Liu, Baiming; Shi, Xiaobin; Fang, Yong; Xu, Baoyun; Zhou, Xuguo; Zhang, Youjun

    2013-01-01

    Background The sweetpotato whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae), is one of the most widely distributed agricultural pests. Although it has developed resistance to many registered insecticides including the neonicotinoid insecticide thiamethoxam, the mechanisms that regulate the resistance are poorly understood. To understand the molecular basis of thiamethoxam resistance, “omics” analyses were carried out to examine differences between resistant and susceptible B. tabaci at both transcriptional and translational levels. Results A total of 1,338 mRNAs and 52 proteins were differentially expressed between resistant and susceptible B. tabaci. Among them, 11 transcripts had concurrent transcription and translation profiles. KEGG analysis mapped 318 and 35 differentially expressed genes and proteins, respectively, to 160 and 59 pathways (p<0.05). Thiamethoxam treatment activated metabolic pathways (e.g., drug metabolism), in which 118 transcripts were putatively linked to insecticide resistance, including up-regulated glutathione-S-transferase, UDP glucuronosyltransferase, glucosyl/glucuronosyl transferase, and cytochrome P450. Gene Ontology analysis placed these genes and proteins into protein complex, metabolic process, cellular process, signaling, and response to stimulus categories. Quantitative real-time PCR analysis validated “omics” response, and suggested a highly overexpressed P450, CYP6CX1, as a candidate molecular basis for the mechanistic study of thiamethoxam resistance in whiteflies. Finally, enzymatic activity assays showed elevated detoxification activities in the resistant B. tabaci. Conclusions This study demonstrates the applicability of high-throughput omics tools for identifying molecular candidates related to thiamethoxam resistance in an agricultural important insect pest. In addition, transcriptomic and proteomic analyses provide a solid foundation for future functional investigations into the complex molecular mechanisms

  3. Cofoundress relatedness and group productivity in colonies of social Dunatothrips (Insecta: Thysanoptera) on Australian Acacia

    PubMed Central

    Bono, Jeremy M.; Crespi, Bernard J.

    2015-01-01

    Facultative joint colony founding by social insects provides opportunities to analyze the roles of genetic and ecological factors in the evolution of cooperation. Although cooperative nesting is observed in range of social insect taxa, the most detailed studies of this behavior have been conducted with Hymenoptera (ants, bees, and wasps). Here, we show that foundress associations in the haplodiploid social thrips Dunatothrips aneurae (Insecta: Thysanoptera) are most often comprised of close relatives (sisters), though groups with unrelated foundresses are also found. Associations among relatives appear to be facilitated by limited female dispersal, which results in viscous population structure. In addition, we found that per capita productivity declined with increasing group size, sex ratios were female-biased, and some female offspring apparently remained in their natal domicile for some time following eclosion. D. aneurae thus exhibits a suite of similarities with eusocial Hymenoptera, providing evidence for the convergent evolution of associated social and life-history traits in Hymenoptera and Thysanoptera. PMID:26279604

  4. Selection of Lecanicillium Strain with High Virulence against Developmental Stages of Bemisia tabaci

    PubMed Central

    Park, Heeyong

    2010-01-01

    Selection of fungal strains with high virulence against the developmental stages of Bemisia tabaci was performed using internal transcribed spacer regions. The growth rate of hyphae was measured and bioassay of each developmental stage of B. tabaci was conducted for seven days. All of the fungal strains tested were identified as Lecanicillium spp., with strain 4078 showing the fastest mycelium growth rate (colony diameter, 16.3 ± 0.9 mm) among the strains. Compared to strain 4075, which showed the slowest growth rate, the growth rate of strain 4078 was increased almost 2-fold after seven days. Strains 4078 and Btab01 were most virulent against the egg and larva stages, respectively. The virulence of fungal strains against the adult stage was high, except for strains 41185 and 3387. Based on the growth rate of mycelium and level of virulence, strains 4078 and Btab01 were selected as the best fungal strains for application to B. tabaci, regardless of developmental stage. PMID:23956657

  5. Odor, Not Performance, Dictates Bemisia tabaci's Selection between Healthy and Virus Infected Plants

    PubMed Central

    Chen, Gong; Su, Qi; Shi, Xiaobin; Liu, Xin; Peng, Zhengke; Zheng, Huixin; Xie, Wen; Xu, Baoyun; Wang, Shaoli; Wu, Qingjun; Zhou, Xuguo; Zhang, Youjun

    2017-01-01

    Although, insect herbivores are generally thought to select hosts that favor the fitness of their progeny, this “mother-knows-best” hypothesis may be challenged by the presence of a plant virus. Our previous study showed that the whitefly, Bemisia tabaci, the obligate vector for transmitting Tomato yellow leaf curl virus (TYLCV), preferred to settle and oviposit on TYLCV-infected rather than healthy host plant, Datura stramonium. The performances of B. tabaci larvae and adults were indeed improved on virus-infected D. stramonium, which is consistent with “mother-knows-best” hypothesis. In this study, B. tabaci Q displayed the same preference to settle and oviposit on Tomato spotted wilt virus (TSWV)-infected host plants, D. stramonium and Capsicum annuum, respectively. As a non-vector of TSWV, however, insect performance was impaired since adult body size, longevity, survival, and fecundity were reduced in TSWV infected D. stramonium. This appears to be an odor-mediated behavior, as plant volatile profiles are modified by viral infection. Infected plants have reduced quantities of o-xylene and α-pinene, and increased levels of phenol and 2-ethyl-1-hexanol in their headspace. Subsequent behavior experiments showed that o-xylene and α-pinene are repellant, while phenol and 2-ethyl-1-hexanol are attractive. This indicates that the preference of B. tabaci for virus-infected plants is modulated by the dynamic changes in the volatile profiles rather than the subsequent performances on virus-infected plants. PMID:28360861

  6. Asymmetric consequences of host plant occupation on the competition between the whiteflies Bemisia tabaci cryptic species MEAM1 and Trialeurodes vaporariorum (Hemiptera: Aleyrodidae).

    PubMed

    Zhang, Gui-Fen; Lövei, Gábor L; Hu, Man; Wan, Fang-Hao

    2014-12-01

    The two common whitefly species, Bemisia tabaci (Gennadius) MEAM1 and Trialeurodes vaporariorum (Westwood), often co-occur on their host plants. The effect of host plant occupation by one species on later-arriving conspecific individuals or on the other competing species was examined. Resource preoccupied by T. vaporariorum had mostly negative effects on the life history parameters of later-arriving conspecifics. Red-eyed nymph and immature survival of T. vaporariorum decreased when resource was preoccupied by conspecifics, irrespective of the previous occupation scenario. However, resource preoccupied by T. vaporariorum had only minor detrimental effects on the performance of later-arriving B. tabaci MEAM1. In the opposite colonisation sequence, previous occupation by B. tabaci MEAM1 had no significant effects on the life history parameters of later-arriving conspecifics, but severe detrimental effects were observed on the performance of later-arriving T. vaporariorum. Total immature survival of T. vaporariorum decreased in both weak and strong previous occupation situations by B. tabaci MEAM1. The interspecific interactions between B. tabaci MEAM1 and T. vaporariorum were asymmetric, with B. tabaci MEAM1 being the superior competitor. This superiority could partially explain the rapid spread of B. tabaci MEAM1 in China. © 2013 Society of Chemical Industry.

  7. Members of Bemisia tabaci (Hemiptera: Aleyrodidae) Cryptic Species and the Status of Two Invasive Alien Species in the Yunnan Province (China)

    PubMed Central

    Hu, Jian; Jiang, Zhi-Lin; Nardi, Francesco; Liu, Yuan-Yuan; Luo, Xiao-Rong; Li, Hong-Xiang; Zhang, Zhong-Kai

    2014-01-01

    Abstract Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a cryptic species complex that includes some of the most significant pests of agriculture and horticulture worldwide. To understand the diversity and distribution of B. tabaci cryptic species in Yunnan, a famous biodiversity hotspot in China, a large-scale sampling was conducted from year 2010 to 2013 in 10 prefectures. Mitochondrial cytochrome oxidase I gene sequences were used to identify different cryptic species. Phylogenetic analyses were performed using Bayesian methods to assess the position of a new B. tabaci cryptic species in the context of the B. tabaci diversity in Asia. The survey indicates at least eight B. tabaci cryptic species are present in Yunnan, two invasive (MEAM1 and MED) and six indigenous (China 2, China3, China 4, Asia I, Asia II 1, and Asia II 6), MEAM1, MED, and Asia I being the three predominant cryptic species in Yunnan. Compared with MEAM1, MED has a wider distribution. Based on molecular data, a new cryptic species, here named China 4, was identified that appears to be related to China 1, China 2, and China 3. Future efforts should focus on the interactions between predominant B. tabaci cryptic species and begomoviruses and on the development of effective control strategies. PMID:25502045

  8. Response of Bemisia tabaci Genn. (Hemiptera: Aleyrodidae) biotype B to genotypes of pepper Capsicum annuum (Solanales: Solanaceae).

    PubMed

    Ballina-Gomez, H; Ruiz-Sanchez, E; Chan-Cupul, W; Latournerie-Moreno, L; Hernández-Alvarado, L; Islas-Flores, I; Zuñiga-Aguilar, J J

    2013-04-01

    Bemisia tabaci Genn. biotype B is a widely distributed plant pest that represents one of the major constraints for horticultural crop production. The purpose of the present work was to evaluate the oviposition preference, survivorship, and development of B. tabaci biotype B on semi-cultivated genotypes of Capsicum annuum from southeast Mexico. In free-choice experiments to evaluate the oviposition preference, lower number of eggs laid by B. tabaci biotype B was observed in the genotypes Maax and Xcat´ik relative to that in the commercial genotype Parado. Egg hatchability was significantly lower in Pico Paloma, Bolita, Blanco, Chawa, Payaso, and Xcat´ik than in the rest of the genotypes, including the commercial genotype Jalapeño. Likewise, survivorship of nymphs was significantly lower in Pico Paloma, Bolita, and Blanco than in the remaining genotypes. Nymph developmental time and the period of development from egg to adult were the shortest in Amaxito. Therefore, sources of resistance to B. tabaci biotype B by antibiosis (accumulation of plant defense compounds) might be found in the semi-cultivated genotypes Pico Paloma, Bolita, and Blanco.

  9. Repellent Effects of Different Celery Varieties in Bemisia tabaci (Hemiptera: Aleyrodidae) Biotype Q.

    PubMed

    Tu, Hongtao; Qin, Yuchuan

    2017-06-01

    Y-tube olfactometer and net cages experiments were used to investigate the repellent effects of different celery varieties in biotype Q of sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), on cucumber, Cucumis sativus L. (Cucurbitaceae). Y-tube olfactometer tests showed that whiteflies have strong repellent behavior to different celery varieties. Intercropping different celery varieties with cucumbers had significant repellent effects and oviposition deterrent effects in whiteflies. Results obtained demonstrated that the Western Europe celery varieties, Juventus and Ventura, and the Chinese celery variety, Jinnan, had good repellent efficacy against the whitefly. D-Limonene, β-myrcene, and (E)-β-ocimene might be the main active components in celery that affected the selection behavior of B. tabaci. In Western Europe celery varieties, D-limonene was the main volatile component for the repellent effects in B. tabaci; however, the two Chinese celery varieties that showed repellent effects had relatively higher volatilization quantities of β-myrcene than of D-limonene. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  10. Use of fluorescence, a novel technique to determine reduction in Bemisia tabaci (Hemiptera: Aleyrodidae) nymph feeding when exposed to Benevia and other insecticides.

    PubMed

    Cameron, Rachel; Lang, Edward B; Annan, I Billy; Portillo, Hector E; Alvarez, Juan M

    2013-04-01

    The sweet potato whitefly, Bemisia tabaci (Gennadius), is an economically important pest in the United States and other countries. Growers in many places rely on the use of insecticides to reduce populations of B. tabaci. However, insecticides may take a few days to cause B. tabaci mortality and some do not reduce feeding before death. Earlier reduction of feeding of whiteflies would decrease the physiological effects on plants, reduce the production of sooty mold and potentially reduce the transmission of viruses. Measuring the reduction in feeding after the exposure of B. tabaci to an insecticide has proven difficult. This series of laboratory experiments demonstrate the usefulness of fluorescence in determining B. tabaci feeding cessation. Fluorescein sodium salt is systemically transported in the xylem from the roots to the plant leaves and absorbed by B. tabaci nymphs feeding on these plants. Nymphs start fluorescing shortly after the cotton plant root system is submerged in the fluorescein sodium salt. Using this novel technique, the effect of three insecticides with different modes of action, cyantraniliprole, imidacloprid, and spirotetramat on B. tabaci was evaluated and compared to determine reduction in feeding. Results indicate that B. tabaci nymphs feeding on a plant treated with Benevia have a significant reduction of feeding when compared with nymphs feeding on plants treated with imidacloprid or spirotetramat. Both Benevia and spirotetramat caused significant nymphal mortality by 48 h after exposure. This novel technique will be useful to demonstrate the feeding cessation or reduction in feeding produced by different insecticides in several sucking insect groups.

  11. The suitability of biotypes Q and B of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) at different nymphal instars as hosts for Encarsia formosa Gahan (Hymenoptera: Aphelinidae).

    PubMed

    Liu, Xin; Zhang, Youjun; Xie, Wen; Wu, Qingjun; Wang, Shaoli

    2016-01-01

    Encarsia formosa Gahan (Hymenoptera: Aphelinidae) is a solitary endoparasitoid that is commercially reared and released for augmentative biological control of whiteflies infesting greenhouse crops. In most areas in China, the invasive and destructive whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) biotype Q has replaced B. tabaci biotype B and has become dominant between the two. A better understanding of the suitability of different nymphal instars of B. tabaci biotypes Q and B as hosts for E. formosa is needed to improve the use of this parasitoid for biological control. Parasitism of the four nymphal instars of B. tabaci biotypes Q and B by the commercial strain of E. formosa mass reared on Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae) was assessed in the laboratory. The results indicated that E. formosa parasitized and successfully developed on all instars of both biotypes but performed best on the 3rd instar of B. tabaci biotype B and on the 2nd, 3rd, and 4th instars of B. tabaci biotype Q. The host-feeding rate of the adult parasitoid was generally higher on nymphal instars of B. tabaci biotype Q than on the corresponding nymphal instars of biotype B and was significantly higher on the 2nd and 3rd instars. For both whitefly biotypes, the parasitoid's immature developmental period was the longest on the 1st instar, intermediate on the 2nd and 3rd instars, and the shortest on the 4th instar. The parasitoid emergence rate was significantly lower on the 1st instar than on the other three instars and did not significantly differ between B. tabaci biotype B and biotype Q. Offspring longevity was greater on the 3rd and 4th instars than on the 1st instar and did not significantly differ between the two B. tabaci biotypes. The results indicate that commercially-produced E. formosa can parasitize all instars of B. tabaci biotypes B and Q, making this parasitoid a promising tool for the management of the two biotypes of B. tabaci present in

  12. Non-invasive delivery of dsGST is lethal to the sweet potato whitefly, Bemisia tabaci (G.) (Hemiptera: Aleyrodidae).

    PubMed

    Asokan, R; Rebijith, K B; Roopa, H K; Kumar, N K Krishna

    2015-02-01

    The sweet potato whitefly, Bemisia tabaci (G.) biotype B (Hemiptera: Aleyrodidae), is one of the most economically important pest, by being a dreaded vector of Geminiviruses, and also causes direct damage to the crops by sucking phloem sap. Glutathione S-transferase (GST) is a large family of multifunctional enzymes that play pivotal roles in the detoxification of secondary allelochemical produced by the host plants and in insecticide resistance, thus regulates insect growth and development. The objective of this study is to show the potential of RNA interference (RNAi) in the management of B. tabaci. RNAi is a sequence-specific gene silencing mechanism induced by double-stranded RNA (dsRNA) which holds tremendous potential in pest management. In this regard, we sequenced the GST from B. tabaci and synthesized approximately 500-bp dsRNA from the above and delivered through diet to B. tabaci. Real-time quantitative PCR (RT-qPCR) showed that continuous application of dsGST at 1.0, 0.5, and 0.25 μg/μl reduced mRNA expression levels for BtGST by 77.43, 64.86, and 52.95 % which resulted in mortality by 77, 59, and 40 %, respectively, after 72 h of application. Disruption of BtGST expression will enable the development of novel strategies in pest management and functional analysis of vital genes in B. tabaci.

  13. RNA interference-mediated knockdown of the hydroxyacid-oxoacid transhydrogenase gene decreases thiamethoxam resistance in adults of the whitefly Bemisia tabaci

    PubMed Central

    Yang, Xin; Xie, Wen; Li, Ru-mei; Zhou, Xiao-mao; Wang, Shao-li; Wu, Qing-jun; Yang, Ni-na; Xia, Ji-xing; Yang, Ze-zong; Guo, Li-tao; Liu, Ya-ting; Zhang, You-jun

    2017-01-01

    Bemisia tabaci has developed a high level of resistance to thiamethoxam, a second generation neonicotinoid insecticide that has been widely used to control this pest. In this study, we investigated whether hydroxyacid-oxoacid transhydrogenase (HOT) is involved in resistance to the neonicotinoid insecticide thiamethoxam in the whitefly. We cloned the full-length gene that encodes HOT in B. tabaci. Its cDNA contains a 1428-bp open reading frame encoding 475 amino acid residues. Then we evaluated the mRNA expression level of HOT in different developmental stages, and found HOT expression was significantly greater in thiamethoxam resistance adults than in thiamethoxam susceptible adults. Subsequently, seven field populations of B. tabaci adults were sampled, the expression of mRNA level of HOT significant positive correlated with thiamethoxam resistance level. At last, we used a modified gene silencing system to knock-down HOT expression in B. tabaci adults. The results showed that the HOT mRNA levels decreased by 57% and thiamethoxam resistance decreased significantly after 2 days of feeding on a diet containing HOT dsRNA. The results indicated that down-regulation of HOT expression decreases thiamethoxam resistance in B. tabaci adults. PMID:28117358

  14. Members of Bemisia tabaci (Hemiptera: Aleyrodidae) cryptic species and the status of two invasive alien species in the Yunnan Province (China).

    PubMed

    Hu, Jian; Jiang, Zhi-Lin; Nardi, Francesco; Liu, Yuan-Yuan; Luo, Xiao-Rong; Li, Hong-Xiang; Zhang, Zhong-Kai

    2014-01-01

    Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a cryptic species complex that includes some of the most significant pests of agriculture and horticulture worldwide. To understand the diversity and distribution of B. tabaci cryptic species in Yunnan, a famous biodiversity hotspot in China, a large-scale sampling was conducted from year 2010 to 2013 in 10 prefectures. Mitochondrial cytochrome oxidase I gene sequences were used to identify different cryptic species. Phylogenetic analyses were performed using Bayesian methods to assess the position of a new B. tabaci cryptic species in the context of the B. tabaci diversity in Asia. The survey indicates at least eight B. tabaci cryptic species are present in Yunnan, two invasive (MEAM1 and MED) and six indigenous (China 2, China3, China 4, Asia I, Asia II 1, and Asia II 6), MEAM1, MED, and Asia I being the three predominant cryptic species in Yunnan. Compared with MEAM1, MED has a wider distribution. Based on molecular data, a new cryptic species, here named China 4, was identified that appears to be related to China 1, China 2, and China 3. Future efforts should focus on the interactions between predominant B. tabaci cryptic species and begomoviruses and on the development of effective control strategies. © The Author 2014. Published by Oxford University Press on behalf of the Entomological Society of America.

  15. Qualitative and Quantitative Differences in Herbivore-Induced Plant Volatile Blends from Tomato Plants Infested by Either Tuta absoluta or Bemisia tabaci.

    PubMed

    Silva, Diego B; Weldegergis, Berhane T; Van Loon, Joop J A; Bueno, Vanda H P

    2017-01-01

    Plants release a variety of volatile organic compounds that play multiple roles in the interactions with other plants and animals. Natural enemies of plant-feeding insects use these volatiles as cues to find their prey or host. Here, we report differences between the volatile blends of tomato plants infested with the whitefly Bemisia tabaci or the tomato borer Tuta absoluta. We compared the volatile emission of: (1) clean tomato plants; (2) tomato plants infested with T. absoluta larvae; and (3) tomato plants infested with B. tabaci adults, nymphs, and eggs. A total of 80 volatiles were recorded of which 10 occurred consistently only in the headspace of T. absoluta-infested plants. Many of the compounds detected in the headspace of the two herbivory treatments were emitted at different rates. Plants damaged by T. absoluta emitted at least 10 times higher levels of many compounds compared to plants damaged by B. tabaci and intact plants. The multivariate separation of T. absoluta-infested plants from those infested with B. tabaci was due largely to the chorismate-derived compounds as well as volatile metabolites of C 18 -fatty acids and branched chain amino acids that had higher emission rates from T. absoluta-infested plants, whereas the cyclic sesquiterpenes α- and β-copaene, valencene, and aristolochene were emitted at significantly higher levels from B. tabaci-infested plants. Our findings imply that feeding by T. absoluta and B. tabaci induced emission of volatile blends that differ quantitatively and qualitatively, providing a chemical basis for the recently documented behavioral discrimination by two generalist predatory mirid species, natural enemies of T. absoluta and B. tabaci employed in biological control.

  16. Salicylic acid is required for Mi-1-mediated resistance of tomato to whitefly Bemisia tabaci, but not for basal defense to this insect pest.

    PubMed

    Rodríguez-Álvarez, C I; López-Climent, M F; Gómez-Cadenas, A; Kaloshian, I; Nombela, G

    2015-10-01

    Plant defense to pests or pathogens involves global changes in gene expression mediated by multiple signaling pathways. A role for the salicylic acid (SA) signaling pathway in Mi-1-mediated resistance of tomato (Solanum lycopersicum) to aphids was previously identified and its implication in the resistance to root-knot nematodes is controversial, but the importance of SA in basal and Mi-1-mediated resistance of tomato to whitefly Bemisia tabaci had not been determined. SA levels were measured before and after B. tabaci infestation in susceptible and resistant Mi-1-containing tomatoes, and in plants with the NahG bacterial transgene. Tomato plants of the same genotypes were also screened with B. tabaci (MEAM1 and MED species, before known as B and Q biotypes, respectively). The SA content in all tomato genotypes transiently increased after infestation with B. tabaci albeit at variable levels. Whitefly fecundity or infestation rates on susceptible Moneymaker were not significantly affected by the expression of NahG gene, but the Mi-1-mediated resistance to B. tabaci was lost in VFN NahG plants. Results indicated that whiteflies induce both SA and jasmonic acid accumulation in tomato. However, SA has no role in basal defense of tomato against B. tabaci. In contrast, SA is an important component of the Mi-1-mediated resistance to B. tabaci in tomato.

  17. Unravelling the Genetic Diversity among Cassava Bemisia tabaci Whiteflies Using NextRAD Sequencing.

    PubMed

    Wosula, Everlyne N; Chen, Wenbo; Fei, Zhangjun; Legg, James P

    2017-11-01

    Bemisia tabaci threatens production of cassava in Africa through vectoring viruses that cause cassava mosaic disease (CMD) and cassava brown streak disease (CBSD). B. tabaci sampled from cassava in eight countries in Africa were genotyped using NextRAD sequencing, and their phylogeny and population genetics were investigated using the resultant single nucleotide polymorphism (SNP) markers. SNP marker data and short sequences of mitochondrial DNA cytochrome oxidase I (mtCOI) obtained from the same insect were compared. Eight genetically distinct groups were identified based on mtCOI, whereas phylogenetic analysis using SNPs identified six major groups, which were further confirmed by PCA and multidimensional analyses. STRUCTURE analysis identified four ancestral B. tabaci populations that have contributed alleles to the six SNP-based groups. Significant gene flows were detected between several of the six SNP-based groups. Evidence of gene flow was strongest for SNP-based groups occurring in central Africa. Comparison of the mtCOI and SNP identities of sampled insects provided a strong indication that hybrid populations are emerging in parts of Africa recently affected by the severe CMD pandemic. This study reveals that mtCOI is not an effective marker at distinguishing cassava-colonizing B. tabaci haplogroups, and that more robust SNP-based multilocus markers should be developed. Significant gene flows between populations could lead to the emergence of haplogroups that might alter the dynamics of cassava virus spread and disease severity in Africa. Continuous monitoring of genetic compositions of whitefly populations should be an essential component in efforts to combat cassava viruses in Africa. © The Author(s) 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  18. Transgenic Cotton-Fed Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) Affects the Parasitoid Encarsia desantisi Viggiani (Hymenoptera: Aphelinidae) Development.

    PubMed

    Pessoa, R; Rossi, G D; Busoli, A C

    2016-02-01

    Cotton cultivars expressing Cry proteins are widely used to control lepidopteran pests. The effects of transgenic plants containing insecticidal Cry proteins on non-target species must be comprehended for a better and rational use of this technology for pest management. We investigated the influence of the Bt cotton cultivars NuOPAL and FM 975 on biological parameters of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), a non-target pest of Bt cotton cultivars and on its parasitoid Encarsia desantisi Viggiani (Hymenoptera: Aphelinidae). The experiments were conducted in a climatized room, and the non-transgenic near isolines were used for rearing whiteflies as control hosts. The effects of the Bt cotton cultivars on the period of embryonic and larval development and the percentage of adult emergence of B. tabaci were assessed. The period required for embryonic, larval, and pupal development and the percentage of emergence and longevity of E. desantisi females were determined using Bt cotton-fed and non-Bt cotton-fed B. tabaci as hosts. Both Bt cotton cultivars resulted in a decrease of approximately 20% of adult emergence of B. tabaci. Differently, an increase of approximately 10% of adult emergence of E. desantisi was observed for parasitoids that used hosts fed with both Bt cotton cultivars. However, female parasitoid longevity decreased when their hosts were fed on Bt cotton cultivars. Our data suggest that the use of Bt cotton cultivars in association with the biological control agent E. desantisi could be functional for the management of B. tabaci in Bt cotton crops.

  19. Update on the Status of Bemisia tabaci in the UK and the Use of Entomopathogenic Fungi within Eradication Programmes

    PubMed Central

    Cuthbertson, Andrew G. S.

    2013-01-01

    The sweetpotato whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) continues to be a serious threat to crops worldwide. The UK holds Protected Zone status against this pest and, as a result, B. tabaci entering on plant material is subjected to a policy of eradication. Both B and Q Bemisia biotypes are now regularly intercepted entering the UK. With increasing reports of neonicotinoid resistance in both these biotypes, it is becoming more problematic to control/eradicate. Therefore, alternative means of control are necessary. Entomopathogenic fungi (Lecanicilllium muscarium and Beauveria bassiana) offer much potential as control agents of B. tabaci within eradication programmes in the UK. PMID:26464385

  20. Two cytochrome P450 genes are involved in imidacloprid resistance in field populations of the whitefly, Bemisia tabaci, in China.

    PubMed

    Yang, Xin; Xie, Wen; Wang, Shao-li; Wu, Qing-jun; Pan, Hui-peng; Li, Ru-mei; Yang, Ni-na; Liu, Bai-ming; Xu, Bao-yun; Zhou, Xiaomao; Zhang, You-jun

    2013-11-01

    The sweet potato whitefly, Bemisia tabaci (Gennadius) (Hemiptera:Aleyrodidae), is an invasive and damaging pest of field crops worldwide. The neonicotinoid insecticide imidacloprid has been widely used to control this pest. We assessed the species composition (B vs. Q), imidacloprid resistance, and association between imidacloprid resistance and the expression of five P450 genes for 14-17 B. tabaci populations in 12 provinces in China. Fifteen of 17 populations contained only B. tabaci Q, and two populations contained both B and Q. Seven of 17 populations exhibited moderate to high resistance to imidacloprid, and eight populations exhibited low resistance to imidacloprid, compared with the most susceptible field WHHB population. In a study of 14 of the populations, resistance level was correlated with the expression of the P450 genes CYP6CM1 and CYP4C64 but not with the expression of CYP6CX1, CYP6CX4, or CYP6DZ7. This study indicates that B. tabaci Q has a wider distribution in China than previously reported. Resistance to imidacloprid in field populations of B. tabaci is associated with the increased expression of two cytochrome P450 genes (CYP6CM1 and CYP4C64). Crown Copyright © 2013. Published by Elsevier Inc. All rights reserved.

  1. Toxicological and biochemical basis of synergism between the entomopathogenic fungus Lecanicillium muscarium and the insecticide matrine against Bemisia tabaci (Gennadius)

    NASA Astrophysics Data System (ADS)

    Ali, Shaukat; Zhang, Can; Wang, Zeqing; Wang, Xing-Min; Wu, Jian-Hui; Cuthbertson, Andrew G. S.; Shao, Zhenfang; Qiu, Bao-Li

    2017-04-01

    The sweetpotato whitefly Bemisia tabaci (Gennadius) was challenged with different combinations of matrine (insecticide) and Lecanicillium muscarium (entomopathogenic fungus). Our results revealed a synergistic relationship between matrine and L. muscarium on mortality and enzyme activities of B. tabaci. To illustrate the biochemical mechanisms involved in detoxification and immune responses of B. tabaci against both control agents, activities of different detoxifying and antioxidant enzymes were quantified. After combined application of matrine and L. muscarium, activities of carboxylestrease (CarE), glutathione-s-transferase (GSTs) and chitinase (CHI) decreased during the initial infection period. Acetylcholinestrase (AChE) activities increased during the entire experimental period, whereas those of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) decreased during the later infection period. The increased mortality and suppression of enzymatic response of B. tabaci following matrine and L. muscarium application suggests a strong synergistic effect between both agents. The strong synergistic effect is possibly related to the disturbance of acetylcholine balance and changes in AchE activities of the whitefly as both matrine and L. muscarium target insect acetylcholine (Ach) receptors which in turn effects AchE production. Therefore, our results have revealed the complex biochemical processes involved in the synergistic action of matrine and L. muscarium against B. tabaci.

  2. Transmission of Pantoea ananatis and P. agglomerans, causal agents of center rot of onion (Allium cepa), by onion thrips (Thrips tabaci) through feces.

    PubMed

    Dutta, B; Barman, A K; Srinivasan, R; Avci, U; Ullman, D E; Langston, D B; Gitaitis, R D

    2014-08-01

    Frankliniella fusca, the tobacco thrips, has been shown to acquire and transmit Pantoea ananatis, one of the causal agents of the center rot of onion. Although Thrips tabaci, the onion thrips, is a common pest of onions, its role as a vector of P. ananatis has been unknown. The bacterium, P. agglomerans, is also associated with the center rot of onion, but its transmission by thrips has not been previously investigated. In this study, we investigated the relationship of T. tabaci with P. ananatis and P. agglomerans. Surface-sterilized T. tabaci were provided with various acquisition access periods (AAP) on onion leaves inoculated with either P. ananatis or P. agglomerans. A positive exponential relationship was observed between thrips AAP duration and P. ananatis (R² = 0.967; P = 0.023) or P. agglomerans acquisition (R² = 0.958; P = 0.017). Transmission experiments conducted with T. tabaci adults indicated that 70% of the seedlings developed center rot symptoms 15 days after inoculation. Immunofluorescence microscopy with antibodies specific to P. ananatis revealed that the bacterium was localized only in the gut of T. tabaci adults. Mechanical inoculation of onion seedlings with fecal rinsates alone produced center rot but not with salivary secretions. Together these results suggested that T. tabaci could efficiently transmit P. ananatis and P. agglomerans.

  3. Olfactory response of predatory Macrolophus caliginosus Wagner (Heteroptera: Miridae) to the odours host plant infested by Bemisia tabaci

    NASA Astrophysics Data System (ADS)

    Saad, Khalid A.; Roff, M. N. Mohamad; Salam, Mansour; Hanifah Mohd, Y.; Idris, A. B.

    2014-09-01

    Plant infested with herbivores, release volatile that can be used by natural enemies to locate their herbivorous prey. Laboratory studies were carried out to determine the olfactory responses of predator Macrolophus caliginosus Wagner (Heteroptera: Miridae), to chili plant infected with eggs, nymphs of Bemisia tabaci, using Y-tube olfactometer. The results shown that predator, M. caliginosus has ability to discriminate between non-infested and infested plant by B. tabaci. Moreover, the predator preferred plants with nymphs over plants with eggs. This suggested that M. caliginous uses whitefly-induced volatile as reliable indicators to distinguish between infested chili plants by nymphs, eggs and non-infested plants. These results enhance our understanding of the olfactory cues that guide foraging by M. caliginosus to plant with and without Bemisia tabaci.

  4. DNA Barcoding of Bemisia tabaci Complex (Hemiptera: Aleyrodidae) Reveals Southerly Expansion of the Dominant Whitefly Species on Cotton in Pakistan

    PubMed Central

    Ashfaq, Muhammad; Hebert, Paul D. N.; Mirza, M. Sajjad; Khan, Arif M.; Mansoor, Shahid; Shah, Ghulam S.; Zafar, Yusuf

    2014-01-01

    Background Although whiteflies (Bemisia tabaci complex) are an important pest of cotton in Pakistan, its taxonomic diversity is poorly understood. As DNA barcoding is an effective tool for resolving species complexes and analyzing species distributions, we used this approach to analyze genetic diversity in the B. tabaci complex and map the distribution of B. tabaci lineages in cotton growing areas of Pakistan. Methods/Principal Findings Sequence diversity in the DNA barcode region (mtCOI-5′) was examined in 593 whiteflies from Pakistan to determine the number of whitefly species and their distributions in the cotton-growing areas of Punjab and Sindh provinces. These new records were integrated with another 173 barcode sequences for B. tabaci, most from India, to better understand regional whitefly diversity. The Barcode Index Number (BIN) System assigned the 766 sequences to 15 BINs, including nine from Pakistan. Representative specimens of each Pakistan BIN were analyzed for mtCOI-3′ to allow their assignment to one of the putative species in the B. tabaci complex recognized on the basis of sequence variation in this gene region. This analysis revealed the presence of Asia II 1, Middle East-Asia Minor 1, Asia 1, Asia II 5, Asia II 7, and a new lineage “Pakistan”. The first two taxa were found in both Punjab and Sindh, but Asia 1 was only detected in Sindh, while Asia II 5, Asia II 7 and “Pakistan” were only present in Punjab. The haplotype networks showed that most haplotypes of Asia II 1, a species implicated in transmission of the cotton leaf curl virus, occurred in both India and Pakistan. Conclusions DNA barcodes successfully discriminated cryptic species in B. tabaci complex. The dominant haplotypes in the B. tabaci complex were shared by India and Pakistan. Asia II 1 was previously restricted to Punjab, but is now the dominant lineage in southern Sindh; its southward spread may have serious implications for cotton plantations in this region. PMID

  5. DNA barcoding of Bemisia tabaci complex (Hemiptera: Aleyrodidae) reveals southerly expansion of the dominant whitefly species on cotton in Pakistan.

    PubMed

    Ashfaq, Muhammad; Hebert, Paul D N; Mirza, M Sajjad; Khan, Arif M; Mansoor, Shahid; Shah, Ghulam S; Zafar, Yusuf

    2014-01-01

    Although whiteflies (Bemisia tabaci complex) are an important pest of cotton in Pakistan, its taxonomic diversity is poorly understood. As DNA barcoding is an effective tool for resolving species complexes and analyzing species distributions, we used this approach to analyze genetic diversity in the B. tabaci complex and map the distribution of B. tabaci lineages in cotton growing areas of Pakistan. Sequence diversity in the DNA barcode region (mtCOI-5') was examined in 593 whiteflies from Pakistan to determine the number of whitefly species and their distributions in the cotton-growing areas of Punjab and Sindh provinces. These new records were integrated with another 173 barcode sequences for B. tabaci, most from India, to better understand regional whitefly diversity. The Barcode Index Number (BIN) System assigned the 766 sequences to 15 BINs, including nine from Pakistan. Representative specimens of each Pakistan BIN were analyzed for mtCOI-3' to allow their assignment to one of the putative species in the B. tabaci complex recognized on the basis of sequence variation in this gene region. This analysis revealed the presence of Asia II 1, Middle East-Asia Minor 1, Asia 1, Asia II 5, Asia II 7, and a new lineage "Pakistan". The first two taxa were found in both Punjab and Sindh, but Asia 1 was only detected in Sindh, while Asia II 5, Asia II 7 and "Pakistan" were only present in Punjab. The haplotype networks showed that most haplotypes of Asia II 1, a species implicated in transmission of the cotton leaf curl virus, occurred in both India and Pakistan. DNA barcodes successfully discriminated cryptic species in B. tabaci complex. The dominant haplotypes in the B. tabaci complex were shared by India and Pakistan. Asia II 1 was previously restricted to Punjab, but is now the dominant lineage in southern Sindh; its southward spread may have serious implications for cotton plantations in this region.

  6. Bemisia tabaci MED Population Density as Affected by Rootstock-Modified Leaf Anatomy and Amino Acid Profiles in Hydroponically Grown Tomato

    PubMed Central

    Žanić, Katja; Dumičić, Gvozden; Mandušić, Marija; Vuletin Selak, Gabriela; Bočina, Ivana; Urlić, Branimir; Ljubenkov, Ivica; Bučević Popović, Viljemka; Goreta Ban, Smiljana

    2018-01-01

    Bemisia tabaci is one of the most devastating pests in tomato greenhouse production. Insecticide resistance management for B. tabaci requires a novel approach that maximizes non-chemical methods for pest control. The aim of this study was to test the effects of rootstocks on B. tabaci populations in hydroponically grown tomato plants. In order to contribute to the better understanding of the mechanisms defining the attractiveness of plant to the aerial pest, the effects of rootstocks on leaf anatomy and the amino acid composition of phloem sap were assessed. A two-factorial experimental design was adopted using cultivars (rootstock cultivars and Clarabella) grown as either non-grafted or grafted with cultivar Clarabella as a scion. The rootstock cultivars included Arnold, Buffon, Emperador, and Maxifort. A reduction in B. tabaci density was observed using all rootstock cultivars. The number of adult individuals per leaf was 2.7–5.4 times lower on rootstock cultivars than on Clarabella. The number of large nymphs per square centimeter was at least 24% higher on non–grafted Clarabella compared with all other treatments. The leaf lamina thickness and mesophyll thickness were lower in self-grafted Clarabella than in non-grafted or in one grafted on rootstock cultivars; however, the extent of this reduction depended on the rootstock. The leaves with thinner laminae were generally less attractive to B. tabaci. Eighteen amino acids were detected in the exudates of phloem sap. In all treatments, the most abundant amino acid was γ-aminobutyric acid (GABA), followed by proline, serine, alanine, and histidine. The scion cultivar Clarabella was the most attractive to B. tabaci and had a higher content of leucine than did rootstock cultivars, and a higher content of lysine compared to Buffon and Maxifort. The features modified by rootstock such are changes in leaf anatomy can affect the attractiveness of plants to B. tabaci. Thus, the grafting of tomato could constitute a

  7. Characterization of Antixenosis in Soybean Genotypes to Bemisia tabaci (Hemiptera: Aleyrodidae) Biotype B.

    PubMed

    Baldin, E L L; Cruz, P L; Morando, R; Silva, I F; Bentivenha, J P F; Tozin, L R S; Rodrigues, T M

    2017-08-01

    Bemisia tabaci biotype B (Gennadius) is one of the most important soybean pest worldwide. Herein, 15 soybean genotypes were evaluated, to characterize the occurrence of antixenosis to B. tabaci biotype B. Initially, a multiple-choice test with all genotypes was carried out, evaluating the settling and oviposition preference at 3 d after infestation, and the colonization by nymphs after 48 d of infestation. Subsequently, a no-choice test, using 14 genotypes, was conducted with infested plants individually, and the number of eggs was counted after 72 h. Then, 10 genotypes were selected (indicative of resistance and susceptibility), which were evaluated for whitefly settling 24, 48, and 72 h after infestation and for oviposition 72 h after infestation. The trichomes of the leaflets were characterized for density, size, and inclination to establish possible correlations with the settling and oviposition in the genotypes. In the first multiple-choice test, involving 15 genotypes, 'IAC-17,' 'IAC-19,' and UX-2569-159 expressed antixenosis against B. tabaci. 'Jackson,' 'P98Y11,' and PI-229358 exhibited the same behavior in the no-choice test. In the multiple-choice test, 'Jackson,' 'P98Y11,' and 'TMG1176 RR' were the least attractive and least used for oviposition. The antixenosis shown by 'Jackson,' 'P98Y11,' and PI-229358 may be related to the characteristics of the trichomes (lower density and inclined). Based on the experiments carried out, 'IAC-17,' 'IAC-19,' 'Jackson,' 'P98Y11,' PI-229358, TMG1176 RR, and UX-2569-159 are considered promising for resistance to B. tabaci biotype B and may be exploited in soybean breeding programs for resistance to insects. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  8. Multilocus approach to clarify species status and the divergence history of the Bemisia tabaci (Hemiptera: Aleyrodidae) species complex.

    PubMed

    Hsieh, Chia-Hung; Ko, Chiun-Cheng; Chung, Cheng-Han; Wang, Hurng-Yi

    2014-07-01

    The sweet potato whitefly, Bemisia tabaci, is a highly differentiated species complex. Despite consisting of several morphologically indistinguishable entities and frequent invasions on all continents with important associated economic losses, the phylogenetic relationships, species status, and evolutionary history of this species complex is still debated. We sequenced and analyzed one mitochondrial and three single-copy nuclear genes from 9 of the 12 genetic groups of B. tabaci and 5 closely related species. Bayesian species delimitation was applied to investigate the speciation events of B. tabaci. The species statuses of the different genetic groups were strongly supported under different prior settings and phylogenetic scenarios. Divergence histories were estimated by a multispecies coalescence approach implemented in (*)BEAST. Based on mitochondrial locus, B. tabaci was originated 6.47 million years ago (MYA). Nevertheless, the time was 1.25MYA based on nuclear loci. According to the method of approximate Bayesian computation, this difference is probably due to different degrees of migration among loci; i.e., although the mitochondrial locus had differentiated, gene flow at nuclear loci was still possible, a scenario similar to parapatric mode of speciation. This is the first study in whiteflies using multilocus data and incorporating Bayesian coalescence approaches, both of which provide a more biologically realistic framework for delimiting species status and delineating the divergence history of B. tabaci. Our study illustrates that gene flow during species divergence should not be overlooked and has a great impact on divergence time estimation. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. New putative cryptic species detection and genetic network analysis of Bemisia tabaci (Hempitera: Aleyrodidae) in China based on mitochondrial COI sequences.

    PubMed

    Hu, Jian; Zhang, Xiaoyun; Jiang, Zhilin; Zhang, Feifei; Liu, Yuanyuan; Li, Zhan; Zhang, Zhongkai

    2018-04-01

    The whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a cryptic species complex and widely distributed throughout tropical and subtropical regions. To understand the B. tabaci cryptic species diversity in China more comprehensively, in the year 2014 and 2016, a large-scale sampling was conducted from the famous biodiversity hotspot of China, Yunnan province. Mitochondrial cytochrome oxidase I gene sequences were used to identify new putative cryptic species. Phylogenetic analyses were performed using Bayesian methods to evaluate the position of new cryptic species in the context of the B. tabaci diversity in Asia. Two new cryptic species, China 5 and Asia V were identified. In total, 19 B. tabaci cryptic species are present in China, two invasive (MED and MEAM1) and 17 indigenous. A new sibling species of B. tabaci was first defined and reported. Based on the mtCOI sequences and haplotype network analyses, the genetic diversity of MED was far higher than MEAM1. We confirmed the exotic MED was originated from the western Mediterranean regions and first invaded into Yunnan, China. The genetic structures of other four indigenous species (Asia I, Asia II 1, Asia II 6, and China 1) with relatively wide distribution ranges in China were also discussed.

  10. Transcriptome changes occurred in the whitefly, B. tabaci MEAM1 in response to feeding on melon infected with the crinivirus, CYSDV

    USDA-ARS?s Scientific Manuscript database

    CYSDV, a crinivirus transmitted by the whitefly, B. tabaci, causes widespread losses in melon and other cucurbits. The virus emerged in the southwestern United States in 2006. It established in crops and weeds, and is transmitted to cucurbits by the resident population of B. tabaci MEAM1 each year. ...

  11. Bemisia tabaci MED (Q biotype) (Hemiptera: Aleyrodidae)is on the move in Florida to residential landscapes and may impact open field agriculture

    USDA-ARS?s Scientific Manuscript database

    Bemisia tabaci MED (Mediterranean) have been in the United States for approximately a dozen years spreading to 26 states since it was first detected in Arizona at a retail outlet on poinsettia in 2004. Indistinguishable morphologically from silverleaf whitefly (Bemisia tabaci MEAM1 (Middle Eastern A...

  12. Aphid-induced Defences in Chilli Affect Preferences of the Whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae).

    PubMed

    Saad, Khalid A; Mohamad Roff, M N; Hallett, Rebecca H; Idris, A B

    2015-09-03

    The sweetpotato whitefly (WF), Bemisia tabaci, is a major pest that damages a wide range of vegetable crops in Malaysia. WF infestation is influenced by a variety of factors, including previous infestation of the host plant by other insect pests. This study investigated the effects of previous infestation of host chilli plants by the green peach aphid (Myzus persicae) on the olfactory behavioural response of B. tabaci, using free-choice bioassay with a Y-tube olfactometer. We analysed volatile organic compounds (VOCs) emitted by non-infested and M. persicae-infested chilli plants using solid-phase microextraction and gas chromatography-mass spectrometry. Our results showed that female WFs preferred non-infested to pre-infested plants. Collection and analysis of volatile compounds emitted by infested plants confirmed that there were significant increases in the production of monoterpenes (cymene; 1,8-cineole), sesquiterpenes (β-cadinene, α-copaene), and methyl salicylate (MeSA) compared to non-infested plants. Our results suggest that host plant infestation by aphids may induce production of secondary metabolites that deter B. tabaci from settling on its host plants. These results provide important information for understanding WF host selection and dispersal among crops, and also for manipulating WF behaviour to improve IPM in chilli.

  13. Inoculation of tomato plants with rhizobacteria enhances the performance of the phloem-feeding insect Bemisia tabaci

    PubMed Central

    Shavit, Roee; Ofek-Lalzar, Maya; Burdman, Saul; Morin, Shai

    2013-01-01

    In their natural environment, plants experience multiple biotic interactions and respond to this complexity in an integrated manner. Therefore, plant responses to herbivory are flexible and depend on the context and complexity in which they occur. For example, plant growth promoting rhizobacteria (PGPR) can enhance plant growth and induce resistance against microbial pathogens and herbivorous insects by a phenomenon termed induced systemic resistance (ISR). In the present study, we investigated the effect of tomato (Solanum lycopersicum) pre-inoculation with the PGPR Pseudomonas fluorescens WCS417r, on the performance of the generalist phloem-feeding insect Bemisia tabaci. Based on the ability of P. fluorescens WCS417r to prime for ISR against generalists chewing insects and necrotrophic pathogens, we hypothesized that pre-inoculated plants will strongly resist B. tabaci infestation. In contrast, we discovered that the pre-inoculation treatment increased the tomato plant suitability for B. tabaci which was emphasized both by faster developmental rate and higher survivability of nymph stages on pre-inoculated plants. Our molecular and chemical analyses suggested that the phenomenon is likely to be related to: (I) the ability of the bacteria to reduce the activity of the plant induced defense systems; (II) a possible manipulation by P. fluorescens of the plant quality (in terms of suitability for B. tabaci) through an indirect effect on the rhizosphere bacterial community. The contribution of our study to the pattern proposed for other belowground rhizobacteria and mycorrhizal fungi and aboveground generalist phloem-feeders is discussed. PMID:23964283

  14. Identification of the terebrantian thrips (Insecta, Thysanoptera) associated with cultivated plants in Java, Indonesia

    PubMed Central

    Sartiami, Dewi; Mound, Laurence A.

    2013-01-01

    Abstract An illustrated identification key is provided to 49 species of Thysanoptera, Terebrantia that have been found in association with cultivated plants in Java. This is the first published identification system to this group of insects from Indonesia, and includes 15 species not previously recorded from Indonesia, and a further three species not previously recorded from Java. A table is provided indicating the plants from which thrips were taken. PMID:23794915

  15. Mortality and Population Dynamics of Bemisia tabaci within a Multi-Crop System

    USDA-ARS?s Scientific Manuscript database

    The population dynamics of mobile polyphagous pests is governed by a complex set of interacting factors that involve multiple host-plants, seasonality, movement and demography. Bemisia tabaci is a multivoltine insect with no diapause that maintains population continuity by moving from one host to a...

  16. Wolbachia-mediated parthenogenesis in the predatory thrips Franklinothrips vespiformis (Thysanoptera: Insecta).

    PubMed Central

    Arakaki, N.; Miyoshi, T.; Noda, H.

    2001-01-01

    Wolbachia are bacterial endosymbionts in arthropods and filarial nematodes. They cause thelytoky, which is a form of parthenogenesis in which females produce females without males, in hymenopteran insects. Infection of this parthenogenesis-inducing Wolbachia has been restricted to the order Hymenoptera, but was found in another insect order, Thysanoptera. A parthenogenetic colony of a predatory thrips Franklinothrips vespiformis (Aeolothripidae) possessed B-group Wolbachia. Male progeny were produced from this thrips by heat and tetracycline treatments. Males produced motile sperm, which were transferred to the female spermatheca by mating. However, the mating did not affect the sex ratios of the next generation, suggesting that the sperm do not fertilize the eggs. PMID:11375084

  17. Monitoring changes in bemisia tabaci susceptibility to neonicotinoid insecticides in Arizona and California

    USDA-ARS?s Scientific Manuscript database

    Laboratory bioassays were carried out on field-collected and laboratory strains of Bemisia tabaci to evaluate relative toxicities of four neonicotinoid insecticides: acetamiprid, dinotefuran, imidacloprid and thiamethoxam. Susceptibility to all four neonicotinoids in leaf-uptake bioassays varied co...

  18. Comparative susceptibility of bemisia tabaci to imidacloprid in field- and laboratory-based bioassays

    USDA-ARS?s Scientific Manuscript database

    Bemisia tabaci biotype B is a resistance-prone pest of protected and open agriculture. Systemic uptake bioassays used in resistance monitoring programs have provided important information on susceptibility to neonicotinoid insecticides, but have remained decoupled from field performance. Simultaneou...

  19. Thrips species (Insecta: Thysanoptera) associated with flowers in a restinga fragment in northeastern Brazil.

    PubMed

    Lima, I M B; Almeida-Filho, M A; Lima, M G A; Bonilla, O H; Lima, E F B

    2018-03-22

    With the growing volume of research involving Thysanoptera in Brazil, studies were carried out to improve our understanding of the diversity of thrips in areas where the fauna has historically been neglected. Accordingly, we recorded the diversity of thrips (Insecta: Thysanoptera) associated with a restinga fragment located on the campus of the State University of Ceará (UECE), Fortaleza, Ceará state, and computed the estimated richness and diversity indices. Samples were collected from 2011 through 2013 from flowers of 86 plant species. The material was taken to the Laboratory of Insect-Plant Interaction, where thrips were screened under stereomicroscope. We collected 456 adults and 58 immatures, representing 14 species, in addition to one unidentified species of Treherniella. Microcephalothrips abdominalis was found on a large number of host plants, and Frankliniella insularis was the most common species. About two-thirds of the total richness of thrips species was associated with three plant families (Amaranthaceae, Caesalpiniaceae and Poaceae); six thrips species were each associated with only one plant species. The richness of the species collected was close to that estimated by Bootstrap and Jackknife 1 analysis. The Shannon-Wiener (H') and Simpson (D) diversity indexes were 1,7607 and 0.7769, respectively. Although the species are common, 46 new associations between plant species and thrips were established, 13 of which are true host associations, which demonstrates the importance of coastal vegetation in maintaining populations of thrips.

  20. Standardized molecular diagnostic tool for the identification of cryptic species within the Bemisia tabaci complex.

    PubMed

    Elfekih, Samia; Tay, Wee Tek; Gordon, Karl; Court, Leon N; De Barro, Paul J

    2018-01-01

    The whitefly Bemisia tabaci complex harbours over 40 cryptic species that have been placed in 11 phylogenetically distinct clades based on the molecular characterization of partial mitochondrial DNA COI (mtCOI) gene region. Four cryptic species are currently within the invasive clade, i.e. MED, MEAM1, MEAM2 and IO. Correct identification of these species is a critical step towards implementing reliable measures for plant biosecurity and border protection; however, no standardized B. tabaci-specific primers are currently available which has caused inconsistencies in the species identification processes. We report three sets of polymerase chain reaction (PCR) primers developed to amplify the mtCOI region which can be used for genotyping MED, MEAM1 and IO species, and tested these primers on 91 MED, 35 MEAM1 and five IO individuals. PCR and sequencing of amplicons identified a total of 21, six and one haplotypes in MED, MEAM1 and IO respectively, of which six haplotypes were new to the B. tabaci database. These primer pairs enabled standardization and robust molecular species identification via mtCOI screening of the targeted invasive cryptic species and will improve quarantine decisions. Use of this diagnostic tool could be extended to other species within the complex. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  1. The impact of a parasitic nematode Thripinema fuscum (Tylenchida: Allantonematidae) on the feeding behavior and vector competence of Frankliniella fusca (Thysanoptera: Thripidae)

    USDA-ARS?s Scientific Manuscript database

    Frankliniella fusca (Hinds) (Thysanoptera: Thripidae) is the predominant thrips species found inhabiting and reproducing in peanut (Arachis hypogaea L.) and is one of at least seven thrips species reported to transmit Tomato spotted wilt virus (TSWV). The entomogenous nematode Thripinema fuscum Tipp...

  2. Single basal application of thiacloprid for the integrated management of Meloidogyne incognita and Bemisia tabaci in tomato crops

    NASA Astrophysics Data System (ADS)

    Dong, Sa; Ren, Xiaofen; Zhang, Dianli; Ji, Xiaoxue; Wang, Kaiyun; Qiao, Kang

    2017-01-01

    Tomato growers commonly face heavy nematode (Meloidogyne incognita) and whitefly (B-biotype Bemisia tabaci) infestations, and previous studies demonstrated that thiacloprid could be used to control M. incognita and B. tabaci in cucumber. However, the efficacy of a single basal application of thiacloprid to control both pests and its effect on yield in tomato remains unknown. In this study, the potential of thiacloprid application to the soil for the integrated control of M. incognita and B. tabaci in tomato was evaluated in the laboratory and the field. Laboratory tests showed that thiacloprid was highly toxic to whitefly adults and eggs with an average lethal concentration 50 (LC50) of 14.7 and 62.2 mg ai L-1, respectively, and the LC50 of thiacloprid for nematode J2s and eggs averaged 36.2 and 70.4 mg ai L-1, respectively. In field trials, when thiacloprid was applied to the soil at 7.5, 15 and 30 kg ha-1 in two consecutive years, whitefly adults decreased by 37.8-75.4% within 60 days of treatment, and the root-galling index was reduced by 31.8-85.2%. Optimum tomato plant growth and maximum yields were observed in the 15 kg ha-1 treatment. The results indicated that a single basal application of thiacloprid could control M. incognita and B. tabaci and enhance tomato growth and yield.

  3. Single basal application of thiacloprid for the integrated management of Meloidogyne incognita and Bemisia tabaci in tomato crops

    PubMed Central

    Dong, Sa; Ren, Xiaofen; Zhang, Dianli; Ji, Xiaoxue; Wang, Kaiyun; Qiao, Kang

    2017-01-01

    Tomato growers commonly face heavy nematode (Meloidogyne incognita) and whitefly (B-biotype Bemisia tabaci) infestations, and previous studies demonstrated that thiacloprid could be used to control M. incognita and B. tabaci in cucumber. However, the efficacy of a single basal application of thiacloprid to control both pests and its effect on yield in tomato remains unknown. In this study, the potential of thiacloprid application to the soil for the integrated control of M. incognita and B. tabaci in tomato was evaluated in the laboratory and the field. Laboratory tests showed that thiacloprid was highly toxic to whitefly adults and eggs with an average lethal concentration 50 (LC50) of 14.7 and 62.2 mg ai L−1, respectively, and the LC50 of thiacloprid for nematode J2s and eggs averaged 36.2 and 70.4 mg ai L−1, respectively. In field trials, when thiacloprid was applied to the soil at 7.5, 15 and 30 kg ha−1 in two consecutive years, whitefly adults decreased by 37.8–75.4% within 60 days of treatment, and the root-galling index was reduced by 31.8–85.2%. Optimum tomato plant growth and maximum yields were observed in the 15 kg ha−1 treatment. The results indicated that a single basal application of thiacloprid could control M. incognita and B. tabaci and enhance tomato growth and yield. PMID:28120937

  4. Elevated O3 and TYLCV Infection Reduce the Suitability of Tomato as a Host for the Whitefly Bemisia tabaci

    PubMed Central

    Cui, Hongying; Sun, Yucheng; Chen, Fajun; Zhang, Youjun; Ge, Feng

    2016-01-01

    The effects of elevated atmospheric ozone (O3) levels on herbivorous insects have been well studied, but little is known about the combined effects of elevated O3 and virus infection on herbivorous insect performance. Using open-top chambers in the field, we determined the effects of elevated O3 and Tomato yellow leaf curl virus (TYLCV) infection on wild-type (Wt) tomato and 35S tomato (jasmonic acid (JA) defense-enhanced genotype) in association with whitefly, Bemisia tabaci Gennadius biotype B. Elevated O3 and TYLCV infection, alone and in combination, significantly reduced the contents of soluble sugars and free amino acids, increased the contents of total phenolics and condensed tannins, and increased salicylic acid (SA) content and the expression of SA-related genes in leaves. The JA signaling pathway was upregulated by elevated O3, but downregulated by TYLCV infection and O3 + TYLCV infection. Regardless of plant genotype, elevated O3, TYLCV infection, or O3 + TYLCV infection significantly decreased B. tabaci fecundity and abundance. These results suggest that elevated O3 and TYLCV infection, alone and in combination, reduce the nutrients available for B. tabaci, increase SA content and SA-related gene expression, and increase secondary metabolites, resulting in decreases in fecundity and abundance of B. tabaci in both tomato genotypes. PMID:27916792

  5. Comparative transcriptome analysis reveals networks of genes activated in the whitefly, Bemisia tabaci when fed on tomato plants infected with Tomato yellow leaf curl virus

    USDA-ARS?s Scientific Manuscript database

    The whitefly Bemisia tabaci can transmit hundreds of viruses to numerous agricultural crops in the world. Five genera of viruses, including Begomovirus and Crinivirus, are transmitted by B. tabaci. There is little knowledge about the genes involved in virus acquisition and transmission by whiteflies...

  6. Impact of pymetrozine on Bemisia tabaci (MED whitefly) and Amblyseius swirskii, 2017

    USDA-ARS?s Scientific Manuscript database

    Bemisia tabaci is a polyphagous pest known to feed upon over 900 plant taxa, and is an effective vector of more than 100 plant damaging viruses. Among different biotypes of this cryptic species complex, Middle East-Asia Minor 1 (MEAM1) and Mediterranean (MED) whitefly are the two most destructive me...

  7. Efficacy of Eretmocerus eremicus and flupyradifurone on Bemisia tabaci (MED whitefly), 2017

    USDA-ARS?s Scientific Manuscript database

    Bemisia tabaci is a polyphagous pest known to feed on over 900 plant taxa, and is an effective vector of more than 100 plant damaging viruses. Among different biotypes of this cryptic species complex, Middle East-Asia Minor 1 (MEAM1) and Mediterranean (MED) whitefly are the two most destructive memb...

  8. Efficacy of Eretmocerus eremicus and cyantraniliprole on Bemisia tabaci (MED whitefly), 2017

    USDA-ARS?s Scientific Manuscript database

    Bemisia tabaci (Gennadius) feeds on more than 900 host plants and vectors over 111 plant virus species and is considered to be a major invasive species worldwide. Among different biotypes of this cryptic species complex, MEAM1 and MED whitefly are the two most destructive members posing threats to s...

  9. Effect of dinotefuran on Bemisia tabaci (MED whitefly) and Amblyseius swirskii, 2016

    USDA-ARS?s Scientific Manuscript database

    Bemisia tabaci is a polyphagous pest known to feed upon over 900 plant taxa, and is an effective vector of more than 100 plant damaging viruses. Among different biotypes of this cryptic species complex, MEAM1 and MED whitefly are the two most destructive members posing threats of several crops of ec...

  10. Transcriptome profiling of the whitefly Bemisia tabaci reveals stage-specific gene expression signatures for thiamethoxam resistance

    PubMed Central

    Yang, N; Xie, W; Jones, CM; Bass, C; Jiao, X; Yang, X; Liu, B; Li, R; Zhang, Y

    2013-01-01

    Bemisia tabaci has developed high levels of resistance to many insecticides including the neonicotinoids and there is strong evidence that for some compounds resistance is stage-specific. To investigate the molecular basis of B. tabaci resistance to the neonicotinoid thiamethoxam we used a custom whitefly microarray to compare gene expression in the egg, nymph and adult stages of a thiamethoxam-resistant strain (TH-R) with a susceptible strain (TH-S). Gene ontology and bioinformatic analyses revealed that in all life stages many of the differentially expressed transcripts encoded enzymes involved in metabolic processes and/or metabolism of xenobiotics. Several of these are candidate resistance genes and include the cytochrome P450 CYP6CM1, which has been shown to confer resistance to several neonicotinoids previously, a P450 belonging to the Cytochrome P450s 4 family and a glutathione S-transferase (GST) belonging to the sigma class. Finally several ATP-binding cassette transporters of the ABCG subfamily were highly over-expressed in the adult stage of the TH-R strain and may play a role in resistance by active efflux. Here, we evaluated both common and stage-specific gene expression signatures and identified several candidate resistance genes that may underlie B. tabaci resistance to thiamethoxam. PMID:23889345

  11. Protecting Unrooted Cuttings From Bemisia tabaci (Hemiptera Aleyrodidae) During Propagation

    PubMed Central

    Krauter, Peter C.; Arthurs, Steven

    2017-01-01

    Abstract In North America, the sweetpotato whitefly, Bemisia tabaci Genn., is an important pest of greenhouse poinsettia. Growers have limited options to control this pest during propagation of cuttings, which are rooted under mist for several weeks. Early establishment of this pest increases the difficulty of managing the whitefly and retaining high aesthetic standard during the remaining crop production phase. We evaluated two neonicotinoids with translaminar activity, thiamethoxam (Flagship 25WG), and acetamiprid (TriStar 70 WSP), for control of B. tabaci pre-infested on unrooted cuttings propagated under mist. In an experimental greenhouse, both materials significantly reduced whitefly populations, providing an average reduction of 87.8% and 61.5% total recovered whitefly stages respectively, compared with controls. In another test, dipping cuttings in thiamethoxam (immersion treatment) did not improve control significantly, when compared with foliar sprays applied at label rate. In a commercial greenhouse operation, immersion treatments of thiamethoxam on pre-infested poinsettia cuttings maintained whiteflies at ≤ 0.02/plant, compared with up to 0.33/plant in untreated cuttings. Our data suggest that treating unrooted cuttings before or at the start of propagation can be part of an overall strategy for growers to manage whiteflies in poinsettia production. PMID:28973486

  12. Analysis of Species, Subgroups, and Endosymbionts of Bemisia tabaci (Hemiptera: Aleyrodidae) From Southwestern Cotton Fields in Turkey.

    PubMed

    Karut, Kamil; Mete Karaca, M; Döker, Ismail; Kazak, Cengiz

    2017-08-01

    Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is one of the most important insect pests worldwide including Turkey. Although there are substantial data regarding species composition of Turkish B. tabaci populations, the situation is still not clear and further investigations are needed. Therefore, in this study, species and subgroups of B. tabaci collected from cotton fields in southwestern part of Turkey (Antalya, Aydın, Denizli, and Muğla) were determined using microsatellite analysis, AluI-based mtCOI polymerase chain reaction-random length polymorphism, and sequencing. Secondary endosymbionts were also determined using diagnostic species-specific PCR. Middle East Asia Minor 1 (MEAM1), Mediterranean (MED) Q1, and MED Q2 were the species and subgroups found in this study. The MED species (85.3%) were found to be more dominant than MEAM1. Species status of B. tabaci varied depending on the location. Although all samples collected from Aydın were found to be Q1, three species and subgroups were found in Muğla. Secondary endosymbionts varied according to species and subgroups. Arsenophonus was found only from Q2, while Hamiltonella was detected in MEAM1 and Q1. In addition, high Rickettsia and low Wolbachia infections were detected in MEAM1 and Q1 populations, respectively. In conclusion, for the first time, we report the presence and symbiotic communities of Q1 from Turkey. We also found that the symbiont complement of the Q1 is more congruent with Q1 from Greece than other regions of the world, which may have some interesting implications for movement of this invasive subgroup. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  13. Survey of indigenous entomopathogenic fungi and evaluation of their pathogenicity against the carmine spider mite, Tetranychus cinnabarinus (Boisd.), and the whitefly, Bemisia tabaci (Genn.) biotype B.

    PubMed

    Topuz, Emine; Erler, Fedai; Gumrukcu, Emine

    2016-12-01

    The carmine spider mite, Tetranychus cinnabarinus, and the silverleaf whitefly, Bemisia tabaci, are serious pests of both field- and greenhouse-grown crops in south-western Turkey. Control of these pests has been heavily dependent upon chemical pesticides. The objectives of this study were to investigate the occurrence of indigenous entomopathogenic fungi (EPF) in field populations of T. cinnabarinus and B. tabaci, and to evaluate their pathogenicity against these pests. For this purpose, a survey of EPF isolated from field-collected samples of both pests was carried out in Antalya in 2010 and 2011 using the dilution plating method. Four indigenous Beauveria bassiana isolates (TUR1-B, TUR2-B, FIN1-B, FIN2-B) were recovered. In pathogenicity bioassays with T. cinnabarinus and B. tabaci biotype B, all the isolates tested were pathogenic to some of the biological stages of both pests to varying degrees. FIN1-B and TUR1-B caused mortalities of up to 50 and 45%, respectively, in adults of T. cinnabarinus, and of over 79 and 37%, respectively, in pupae of B. tabaci with 10 7 conidia mL -1 suspensions under laboratory conditions 10 days after inoculation. FIN2-B and TUR2-B had mortalities of 19.45 and 12.28%, respectively, in adults of T. cinnabarinus, and of 6.78 and 8.18%, respectively, in pupae of B. tabaci. None of the isolates had an effect on eggs of either species and larvae of the mite. Overall results suggest that isolates FIN1-B and TUR1-B have potential for management of T. cinnabarinus and B. tabaci. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  14. Implication of the Whitefly Bemisia tabaci Cyclophilin B Protein in the Transmission of Tomato yellow leaf curl virus

    PubMed Central

    Kanakala, Surapathrudu; Ghanim, Murad

    2016-01-01

    Tomato yellow leaf curl virus (TYLCV) is a single-stranded (ssDNA) begomoviruses that causes severe damage to tomato and several other crops worldwide. TYLCV is exclusively transmitted by the sweetpotato whitefly, Bemisia tabaci in a persistent circulative and propagative manner. Previous studies have shown that the transmission, retention, and circulation of TYLCV in its vector involves interaction with insect and endosymbiont proteins, which aid in the transmission of the virus, or have a protective role in response to the presence of the virus in the insect body. However, only a low number of such proteins have been identified. Here, the role of B. tabaci Cyclophilin B (CypB) in the transmission of TYLCV protein was investigated. Cyclophilins are a large family of cellular prolyl isomerases that have many molecular roles including facilitating protein-protein interactions in the cell. One cyclophilin protein has been implicated in aphid-luteovirus interactions. We demonstrate that the expression of CypB from B. tabaci is altered upon TYLCV acquisition and retention. Further experiments used immunocapture-PCR and co-immunolocalization and demonstrated a specific interaction and colocalization between CypB and TYLCV in the the midgut, eggs, and salivary glands. Membrane feeding of anti-CypB antibodies and TYLCV-infected plants showed a decrease in TYLCV transmission, suggesting a critical role that CypB plays in TYLCV transmission. Further experiments, which used membrane feeding with the CypB inhibitor Cyclosporin A showed decrease in CypB-TYLCV colocalization in the midgut and virus transmission. Altogether, our results indicate that CypB plays an important role in TYLCV transmission by B. tabaci. PMID:27895657

  15. Implication of the Whitefly Bemisia tabaci Cyclophilin B Protein in the Transmission of Tomato yellow leaf curl virus.

    PubMed

    Kanakala, Surapathrudu; Ghanim, Murad

    2016-01-01

    Tomato yellow leaf curl virus (TYLCV) is a single-stranded (ssDNA) begomoviruses that causes severe damage to tomato and several other crops worldwide. TYLCV is exclusively transmitted by the sweetpotato whitefly, Bemisia tabaci in a persistent circulative and propagative manner. Previous studies have shown that the transmission, retention, and circulation of TYLCV in its vector involves interaction with insect and endosymbiont proteins, which aid in the transmission of the virus, or have a protective role in response to the presence of the virus in the insect body. However, only a low number of such proteins have been identified. Here, the role of B. tabaci Cyclophilin B (CypB) in the transmission of TYLCV protein was investigated. Cyclophilins are a large family of cellular prolyl isomerases that have many molecular roles including facilitating protein-protein interactions in the cell. One cyclophilin protein has been implicated in aphid-luteovirus interactions. We demonstrate that the expression of CypB from B. tabaci is altered upon TYLCV acquisition and retention. Further experiments used immunocapture-PCR and co-immunolocalization and demonstrated a specific interaction and colocalization between CypB and TYLCV in the the midgut, eggs, and salivary glands. Membrane feeding of anti-CypB antibodies and TYLCV-infected plants showed a decrease in TYLCV transmission, suggesting a critical role that CypB plays in TYLCV transmission. Further experiments, which used membrane feeding with the CypB inhibitor Cyclosporin A showed decrease in CypB-TYLCV colocalization in the midgut and virus transmission. Altogether, our results indicate that CypB plays an important role in TYLCV transmission by B. tabaci .

  16. Transovarial Transmission of Rickettsia spp. and Organ-Specific Infection of the Whitefly Bemisia tabaci

    PubMed Central

    Brumin, Marina; Levy, Maggie

    2012-01-01

    The whitefly Bemisia tabaci is a cosmopolitan insect pest that harbors Portiera aleyrodidarum, the primary obligatory symbiotic bacterium, and several facultative secondary symbionts. Secondary symbionts in B. tabaci are generally associated with the bacteriome, ensuring their vertical transmission; however, Rickettsia is an exception and occupies most of the body cavity, except the bacteriome. The mode of Rickettsia transfer between generations and its subcellular localization in insect organs have not been investigated. Using electron and fluorescence microscopy, we show that Rickettsia infects the digestive, salivary, and reproductive organs of the insect; however, it was not observed in the bacteriome. Rickettsia invades the oocytes during early developmental stages and resides in follicular cells and cytoplasm; it is mostly excluded when the egg matures; however, some bacterial cells remain in the egg, ensuring their transfer to subsequent generations. Rickettsia was localized to testicles and the spermatheca, suggesting a horizontal transfer between males and females during mating. The bacterium was further observed at large amounts in midgut cells, concentrating in vacuole-like structures, and was located in the hemolymph, specifically at exceptionally large amounts around bacteriocytes and in fat bodies. Organs further infected by Rickettsia included the primary salivary glands and stylets, sites of possible secretion of the bacterium outside the whitefly body. The close association between Rickettsia and the B. tabaci digestive system might be important for digestive purposes. The vertical transmission of Rickettsia to subsequent generations occurs via the oocyte and not, like other secondary symbionts, the bacteriome. PMID:22660706

  17. Detection of Cucurbit chlorotic yellows virus from Bemisia tabaci captured on sticky traps using reverse transcription loop-mediated isothermal amplification (RT-LAMP) and simple template preparation.

    PubMed

    Okuda, Mitsuru; Okuda, Shiori; Iwai, Hisashi

    2015-09-01

    Cucurbit chlorotic yellows virus (CCYV) of the genus Crinivirus within the family Closteroviridae is an emerging infectious agent of cucurbits leading to severe disease and significant economic losses. Effective detection and identification methods for this virus are urgently required. In this study, a reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay was developed to detect CCYV from its vector Bemisia tabaci. LAMP primer sets to detect CCYV were evaluated for their sensitivity and specificity, and a primer set designed from the HSP70h gene with corresponding loop primers were selected. The RT-LAMP assay was applied to detect CCYV from viruliferous B. tabaci trapped on sticky traps. A simple extraction procedure using RNAsecure™ was developed for template preparation. CCYV was detected in all of the B. tabaci 0, 1, 7 and 14 days after they were trapped. Although the rise of turbidity was delayed in reactions using RNA from B. tabaci trapped for 7 and 14 days compared with those from 0 and 1 day, the DNA amplification was sufficient to detect CCYV in all of the samples. These findings therefore present a simple template preparation method and an effective RT-LAMP assay, which can be easily and rapidly performed to monitor CCYV-viruliferous B. tabaci in the field. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. A landscape genetic analysis of important agricultural pest species in Tunisia: The whitefly Bemisia tabaci

    PubMed Central

    Fakhfakh, Hatem; Belkadhi, Mohamed Sadok

    2017-01-01

    Combining landscape ecology and genetics provides an excellent framework to appreciate pest population dynamics and dispersal. The genetic architectures of many species are always shaped by environmental constraints. Because little is known about the ecological and genetic traits of Tunisian whitefly populations, the main objective of this work is to highlight patterns of biodiversity, genetic structure and migration routes of this pest. We used nuclear microsatellite loci to analyze B. tabaci populations collected from various agricultural areas across the country and we determine their biotype status. Molecular data were subsequently interpreted in an ecological context supplied from a species distribution model to infer habitat suitability and hereafter the potential connection paths between sampling localities. An analysis of landscape resistance to B. tabaci genetic flow was thus applied to take into account habitat suitability, genetic relatedness and functional connectivity of habitats within a varied landscape matrix. We shed light on the occurrence of three geographically delineated genetic groups with high levels of genetic differentiation within each of them. Potential migration corridors of this pest were then established providing significant advances toward the understanding of genetic features and the dynamic dispersal of this pest. This study supports the hypothesis of a long-distance dispersal of B. tabaci followed by infrequent long-term isolations. The Inference of population sources and colonization routes is critical for the design and implementation of accurate management strategies against this pest. PMID:28972992

  19. A landscape genetic analysis of important agricultural pest species in Tunisia: The whitefly Bemisia tabaci.

    PubMed

    Ben Abdelkrim, Ahmed; Hattab, Tarek; Fakhfakh, Hatem; Belkadhi, Mohamed Sadok; Gorsane, Faten

    2017-01-01

    Combining landscape ecology and genetics provides an excellent framework to appreciate pest population dynamics and dispersal. The genetic architectures of many species are always shaped by environmental constraints. Because little is known about the ecological and genetic traits of Tunisian whitefly populations, the main objective of this work is to highlight patterns of biodiversity, genetic structure and migration routes of this pest. We used nuclear microsatellite loci to analyze B. tabaci populations collected from various agricultural areas across the country and we determine their biotype status. Molecular data were subsequently interpreted in an ecological context supplied from a species distribution model to infer habitat suitability and hereafter the potential connection paths between sampling localities. An analysis of landscape resistance to B. tabaci genetic flow was thus applied to take into account habitat suitability, genetic relatedness and functional connectivity of habitats within a varied landscape matrix. We shed light on the occurrence of three geographically delineated genetic groups with high levels of genetic differentiation within each of them. Potential migration corridors of this pest were then established providing significant advances toward the understanding of genetic features and the dynamic dispersal of this pest. This study supports the hypothesis of a long-distance dispersal of B. tabaci followed by infrequent long-term isolations. The Inference of population sources and colonization routes is critical for the design and implementation of accurate management strategies against this pest.

  20. Global Population Structure of a Worldwide Pest and Virus Vector: Genetic Diversity and Population History of the Bemisia tabaci Sibling Species Group

    PubMed Central

    2016-01-01

    The whitefly Bemisia tabaci sibling species (sibsp.) group comprises morphologically indiscernible lineages of well-known exemplars referred to as biotypes. It is distributed throughout tropical and subtropical latitudes and includes the contemporary invasive haplotypes, termed B and Q. Several well-studied B. tabaci biotypes exhibit ecological and biological diversity, however, most members are poorly studied or completely uncharacterized. Genetic studies have revealed substantial diversity within the group based on a fragment of the mitochondrial cytochrome oxidase I (mtCOI) sequence (haplotypes), with other tested markers being less useful for deep phylogenetic comparisons. The view of global relationships within the B. tabaci sibsp. group is largely derived from this single marker, making assessment of gene flow and genetic structure difficult at the population level. Here, the population structure was explored for B. tabaci in a global context using nuclear data from variable microsatellite markers. Worldwide collections were examined representing most of the available diversity, including known monophagous, polyphagous, invasive, and indigenous haplotypes. Well-characterized biotypes and other related geographic lineages discovered represented highly differentiated genetic clusters with little or no evidence of gene flow. The invasive B and Q biotypes exhibited moderate to high levels of genetic diversity, suggesting that they stemmed from large founding populations that have maintained ancestral variation, despite homogenizing effects, possibly due to human-mediated among-population gene flow. Results of the microsatellite analyses are in general agreement with published mtCOI phylogenies; however, notable conflicts exist between the nuclear and mitochondrial relationships, highlighting the need for a multifaceted approach to delineate the evolutionary history of the group. This study supports the hypothesis that the extant B. tabaci sibsp. group contains

  1. Assessment of Potential Sublethal Effects of Various Insecticides on Key Biological Traits of The Tobacco Whitefly, Bemisia tabaci

    PubMed Central

    He, Yuxian; Zhao, Jianwei; Zheng, Yu; Weng, Qiyong; Biondi, Antonio; Desneux, Nicolas; Wu, Kongming

    2013-01-01

    The tobacco whitefly Bemisia tabaci is one of the most devastating pests worldwide. Current management of B. tabaci relies upon the frequent applications of insecticides. In addition to direct mortality by typical acute toxicity (lethal effect), insecticides may also impair various key biological traits of the exposed insects through physiological and behavioral sublethal effects. Identifying and characterizing such effects could be crucial for understanding the global effects of insecticides on the pest and therefore for optimizing its management in the crops. We assessed the effects of sublethal and low-lethal concentrations of four widely used insecticides on the fecundity, honeydew excretion and feeding behavior of B. tabaci adults. The probing activity of the whiteflies feeding on treated cotton seedlings was recorded by an Electrical Penetration Graph (EPG). The results showed that imidacloprid and bifenthrin caused a reduction in phloem feeding even at sublethal concentrations. In addition, the honeydew excretions and fecundity levels of adults feeding on leaf discs treated with these concentrations were significantly lower than the untreated ones. While, sublethal concentrations of chlorpyrifos and carbosulfan did not affect feeding behavior, honeydew excretion and fecundity of the whitefly. We demonstrated an antifeedant effect of the imidacloprid and bifenthrin on B. tabaci, whereas behavioral changes in adults feeding on leaves treated with chlorpyrifos and carbosulfan were more likely caused by the direct effects of the insecticides on the insects' nervous system itself. Our results show that aside from the lethal effect, the sublethal concentration of imidacloprid and bifenthrin impairs the phloem feeding, i.e. the most important feeding trait in a plant protection perspective. Indeed, this antifeedant property would give these insecticides potential to control insect pests indirectly. Therefore, the behavioral effects of sublethal concentrations of

  2. Monitoring changes in Bemisia tabaci (Hemiptera: Aleyrodidae) susceptibility to neonicotinoid insecticides in Arizona and California.

    PubMed

    Castle, S J; Prabhaker, N

    2013-06-01

    Bemisia tabaci (Gennadius) biotype B is a highly prolific and polyphagous whitefly that established in much of North America during the 1980s. Neonicotinoid insecticides have been fundamental in regaining control over outbreak populations of B. tabaci, but resistance threatens their sustainability. Susceptibility of B. tabaci in the southwestern United States to four neonicotinoid insecticides varied considerably across populations within each year over a 3 yr period. Using a variability ratio of highest LC50 to lowest LC50 in field-collected whitefly adults from Arizona and California, the ranges of LC50(s) across all tests within compounds were highest to imidacloprid and lowest to thiamethoxam. Patterns of susceptibility were similar among all four neonicotinoid insecticides, but the greater variability in responses to imidacloprid and significantly higher LC50(s) attained indicated higher resistance levels to imidacloprid in all field populations. Further evidence of differential toxicities of neonicotinoids was observed in multiple tests of dinotefuran against imidacloprid-resistant lab strains that yielded significant differences in the LC50(s) of dinotefuran and imidacloprid in simultaneous bioassays. To test the possibility that resistance expression in field-collected insects was sometimes masked by stressful conditions, field strains cultured in a greenhouse without insecticide exposure produced significantly higher LC50(s) to all neonicotinoids compared with LC50(s) attained directly from the field. In harsh climates such as the American southwest, resistance expression in field-collected test insects may be strongly influenced by environmental stresses such as high temperatures, overcrowding, and declining host plant quality.

  3. Insecticidal Activity of Chromobacterium subtsugae on the Sweet Potato Whitefly, Bemisia tabaci, Biotype B

    USDA-ARS?s Scientific Manuscript database

    Chromobacterium subtsugae crude extracts contain compounds that are toxic to nymphal and adult Bemisia tabaci. When fed on artificial diet containing 10% of the supernatant of an aqueous cell-free extract of C subtsugae, the number of 2nd and 4th instar nymphs and of emerged adults was significantl...

  4. Aerial electrostatic-charged spray for deposition and efficacy against sweetpotato whitefly (Bemisia tabaci) on cotton

    USDA-ARS?s Scientific Manuscript database

    Efficacy of aerial electrostatic-charged sprays was evaluated for spray deposit characteristics and season-long control of sweet potato whitefly (SWF), Bemisia tabaci biotype B (a.k.a. B. argentifolii), in an irrigated 24-ha cotton field. Treatments included electrostatic-charged sprays at full and ...

  5. Identification of an alternative knockdown resistance (kdr)-like mutation, M918L, and a novel mutation, V1010A, in the Thrips tabaci voltage-gated sodium channel gene.

    PubMed

    Wu, Meixiang; Gotoh, Hiroki; Waters, Timothy; Walsh, Douglas B; Lavine, Laura Corley

    2014-06-01

    Knockdown resistance (kdr) has been identified as a main mechanism against pyrethroid insecticides in many arthropod pests including in the onion thrips, Thrips tabaci. To characterize and identify pyrethroid-resistance in onion thrips in Washington state, we conducted insecticide bioassays and sequenced a region of the voltage gated sodium channel gene from several different T. tabaci populations. Field collected Thrips tabaci were found to have large variations in resistance to the pyrethroid insecticide lambda-cyhalothrin. We identified two single nucleotide substitutions in our analysis of a partial sequence of the T. tabaci voltage-gated sodium channel gene. One mutation resulted in the non-synonymous substitution of methionine with leucine (M918L), which is well known to be responsible for super knockdown resistance in some pest species. Another non-synonymous substitution, a valine (GTT) to alanine (GCT) replacement at amino acid 1010 (V1010A) was identified in our study and was associated with lambda-cyhalothrin resistance. We have characterized a known kdr mutation and identified a novel mutation in the voltage-gated sodium channel gene of Thrips tabaci associated with resistance to lambda-cyhalothrin. This gene region and these mutations are expected to be useful in the development of a diagnostic test to detect kdr resistance in many onion thrips populations. © 2013 Society of Chemical Industry.

  6. Insecticide resistance status in the whitefly, Bemisia tabaci genetic groups Asia-I, Asia-II-1 and Asia-II-7 on the Indian subcontinent

    PubMed Central

    Naveen, N. C.; Chaubey, Rahul; Kumar, Dinesh; Rebijith, K. B.; Rajagopal, Raman; Subrahmanyam, B.; Subramanian, S.

    2017-01-01

    The present study is a summary of the current level of the insecticide resistance to selected organophosphates, pyrethroids, and neonicotinoids in seven Indian field populations of Bemisia tabaci genetic groups Asia-I, Asia-II-1, and Asia-II-7. Susceptibility of these populations was varied with Asia-II-7 being the most susceptible, while Asia-I and Asia-II-1 populations were showing significant resistance to these insecticides. The variability of the LC50 values was 7x for imidacloprid and thiamethoxam, 5x for monocrotophos and 3x for cypermethrin among the Asia-I, while, they were 7x for cypermethrin, 6x for deltamethrin and 5x for imidacloprid within the Asia-II-1 populations. When compared with the most susceptible, PUSA population (Asia-II-7), a substantial increase in resistant ratios was observed in both the populations of Asia-I and Asia-II-1. Comparative analysis during 2010–13 revealed a decline in susceptibility in Asia-I and Asia-II-1 populations of B. tabaci to the tested organophosphate, pyrethroid, and neonicotinoid insecticides. Evidence of potential control failure was detected using probit analysis estimates for cypermethrin, deltamethrin, monocrotophos and imidacloprid. Our results update resistance status of B. tabaci in India. The implications of insecticide resistance management of B. tabaci on Indian subcontinent are discussed. PMID:28098188

  7. [Genetic variability of the Bemisia tabaci (Gennadius) biotype B (Hemiptera: Aleyrodidae) in vegetable crops in São Luís, state of Maranhão, Brazil].

    PubMed

    Da Silva, Maria C; De Lemos, Raimunda N S; Lima, Luzia H C; Gourlart Filho, Luiz R; Pereira, Silma R F

    2009-01-01

    The RAPD technique is widely used to investigate the distinct genetic characteristics of the complex Bemisia tabaci (Gennadius), which is currently constituted of approximately 41 biotypes. The objective of this research was to characterize populations of whitefly collected in crops of agricultural producing areas in São Luís, MA, like okra, beans and pepper, using RAPD molecular markers. Females from nine whitefly populations were analyzed and compared with B. tabaci biotype B taken from poinsettia culture of Embrapa Genetic Resources and Biotechnology (Brasília, DF). Twelve out of the 20 primers tested produced specific band patterns suitable to confirm that the evaluated specimens belong to the biotype B of B. tabaci, despite the high percentage of detected polymorphism. The analysis of the 96 RAPD molecular markers generated indicated that the populations on okra, beans and pepper were grouped according to the host cultures, sharing 80, 76 and 45% of genetic similarity, respectively, when compared with the control population of B. tabaci biotype B. A lower selective pressure was observed with the population of whitefly collected on pepper and minor genetic variability in the whitefly populations collected on okra and bean, when compared with the control population.

  8. Genome sequencing of the sweetpotato whitefly Bemisia tabaci MED/Q.

    PubMed

    Xie, Wen; Chen, Chunhai; Yang, Zezhong; Guo, Litao; Yang, Xin; Wang, Dan; Chen, Ming; Huang, Jinqun; Wen, Yanan; Zeng, Yang; Liu, Yating; Xia, Jixing; Tian, Lixia; Cui, Hongying; Wu, Qingjun; Wang, Shaoli; Xu, Baoyun; Li, Xianchun; Tan, Xinqiu; Ghanim, Murad; Qiu, Baoli; Pan, Huipeng; Chu, Dong; Delatte, Helene; Maruthi, M N; Ge, Feng; Zhou, Xueping; Wang, Xiaowei; Wan, Fanghao; Du, Yuzhou; Luo, Chen; Yan, Fengming; Preisser, Evan L; Jiao, Xiaoguo; Coates, Brad S; Zhao, Jinyang; Gao, Qiang; Xia, Jinquan; Yin, Ye; Liu, Yong; Brown, Judith K; Zhou, Xuguo Joe; Zhang, Youjun

    2017-05-01

    The sweetpotato whitefly Bemisia tabaci is a highly destructive agricultural and ornamental crop pest. It damages host plants through both phloem feeding and vectoring plant pathogens. Introductions of B. tabaci are difficult to quarantine and eradicate because of its high reproductive rates, broad host plant range, and insecticide resistance. A total of 791 Gb of raw DNA sequence from whole genome shotgun sequencing, and 13 BAC pooling libraries were generated by Illumina sequencing using different combinations of mate-pair and pair-end libraries. Assembly gave a final genome with a scaffold N50 of 437 kb, and a total length of 658 Mb. Annotation of repetitive elements and coding regions resulted in 265.0 Mb TEs (40.3%) and 20 786 protein-coding genes with putative gene family expansions, respectively. Phylogenetic analysis based on orthologs across 14 arthropod taxa suggested that MED/Q is clustered into a hemipteran clade containing A. pisum and is a sister lineage to a clade containing both R. prolixus and N. lugens. Genome completeness, as estimated using the CEGMA and Benchmarking Universal Single-Copy Orthologs pipelines, reached 96% and 79%. These MED/Q genomic resources lay a foundation for future 'pan-genomic' comparisons of invasive vs. noninvasive, invasive vs. invasive, and native vs. exotic Bemisia, which, in return, will open up new avenues of investigation into whitefly biology, evolution, and management. © The Author 2017. Published by Oxford University Press.

  9. Identification and characterization of functional aquaporin water channel protein from alimentary tract of whitefly, Bemisia tabaci

    USDA-ARS?s Scientific Manuscript database

    Some hemipteran xylem and phloem feeding insects have evolved specialized alimentary structures or filter chambers that rapidly transport water for excretion or osmoregulation. In the whitefly, Bemisia tabaci, mass movement of water through opposing alimentary tract tissues within the filter chamber...

  10. Implication of the Bacterial Endosymbiont Rickettsia spp. in Interactions of the Whitefly Bemisia tabaci with Tomato yellow leaf curl virus

    PubMed Central

    Kliot, Adi; Cilia, Michelle; Czosnek, Henryk

    2014-01-01

    ABSTRACT Numerous animal and plant viruses are transmitted by arthropod vectors in a persistent, circulative manner. Tomato yellow leaf curl virus (TYLCV) is transmitted by the sweet potato whitefly Bemisia tabaci. We report here that infection with Rickettsia spp., a facultative endosymbiont of whiteflies, altered TYLCV-B. tabaci interactions. A B. tabaci strain infected with Rickettsia acquired more TYLCV from infected plants, retained the virus longer, and exhibited nearly double the transmission efficiency compared to an uninfected B. tabaci strain with the same genetic background. Temporal and spatial antagonistic relationships were discovered between Rickettsia and TYLCV within the whitefly. In different time course experiments, the levels of virus and Rickettsia within the insect were inversely correlated. Fluorescence in situ hybridization analysis of Rickettsia-infected midguts provided evidence for niche exclusion between Rickettsia and TYLCV. In particular, high levels of the bacterium in the midgut resulted in higher virus concentrations in the filter chamber, a favored site for virus translocation along the transmission pathway, whereas low levels of Rickettsia in the midgut resulted in an even distribution of the virus. Taken together, these results indicate that Rickettsia, by infecting the midgut, increases TYLCV transmission efficacy, adding further insights into the complex association between persistent plant viruses, their insect vectors, and microorganism tenants that reside within these insects. IMPORTANCE Interest in bacterial endosymbionts in arthropods and many aspects of their host biology in agricultural and human health systems has been increasing. A recent and relevant studied example is the influence of Wolbachia on dengue virus transmission by mosquitoes. In parallel with our recently studied whitefly-Rickettsia-TYLCV system, other studies have shown that dengue virus levels in the mosquito vector are inversely correlated with

  11. Leaf Morphological Characters Can Be a Factor for Intra-Varietal Preference of Whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) among Eggplant Varieties.

    PubMed

    Hasanuzzaman, Abu Tayeb Mohammad; Islam, Md Nazrul; Zhang, Yi; Zhang, Chen-Yang; Liu, Tong-Xian

    2016-01-01

    The sweetpotato whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae) MEAM1, is considered a serious pest of horticultural and many other crops. While eggplant (Solanum melongena) is one of the most favored host plants, the whiteflies exhibit preferences among different varieties. We hypothesized that certain morphological leaf characteristics of different varieties, like leaf trichome density, trichome length, leaf lamina thickness and leaf color, may affect whitefly landing, feeding and oviposition. In this study, we investigated the variation in leaf morphological characters among selected eggplant varieties and evaluated the effect of these leaf characteristics in rendering eggplant varieties either susceptible or resistant to B. tabaci. We evaluated eight eggplant varieties in choice feeding tests, and we found that the varieties JinSheng Zilongchangqie (JSZ) and H149 were the highly preferred varieties with the highest numbers of whitefly adults and eggs. Significantly lower numbers of whitefly adult eggs were found on the resistant variety Tuo Lu Bamu (TLB). The varieties JinGuangbo Luqie (JGL), JinGuangbo Ziquanqie (JGZ), DaYang Ziguanqie (DYZ), QinXing Ziguanqie (QXZ), and QinXing Niuxinqie (QXN) were moderately favored by B. tabaci. Leaf trichome density, trichome length and leaf lamina thickness were positively correlated with numbers of whitefly adults and eggs. B. tabaci was less attracted to the leaves that reflect long and middle wavelength light (higher R and G values) than to the bright green leaves (medium G value), but the short wavelength light (higher B value) had no significant effect on whitefly preference. The degree of hue had a positive effect, and saturation and brightness had a negative effect on whitefly attraction.

  12. The Whitefly Bemisia tabaci Knottin-1 Gene Is Implicated in Regulating the Quantity of Tomato Yellow Leaf Curl Virus Ingested and Transmitted by the Insect

    PubMed Central

    Hariton Shalev, Aliza; Sobol, Iris; Ghanim, Murad; Liu, Shu-Sheng; Czosnek, Henryk

    2016-01-01

    The whitefly Bemisia tabaci is a major pest to agricultural crops. It transmits begomoviruses, such as Tomato yellow leaf curl virus (TYLCV), in a circular, persistent fashion. Transcriptome analyses revealed that B. tabaci knottin genes were responsive to various stresses. Upon ingestion of tomato begomoviruses, two of the four knottin genes were upregulated, knot-1 (with the highest expression) and knot-3. In this study, we examined the involvement of B. tabaci knottin genes in relation to TYLCV circulative transmission. Knottins were silenced by feeding whiteflies with knottin dsRNA via detached tomato leaves. Large amounts of knot-1 transcripts were present in the abdomen of whiteflies, an obligatory transit site of begomoviruses in their circulative transmission pathway; knot-1 silencing significantly depleted the abdomen from knot-1 transcripts. Knot-1 silencing led to an increase in the amounts of TYLCV ingested by the insects and transmitted to tomato test plants by several orders of magnitude. This effect was not observed following knot-3 silencing. Hence, knot-1 plays a role in restricting the quantity of virions an insect may acquire and transmit. We suggest that knot-1 protects B. tabaci against deleterious effects caused by TYLCV by limiting the amount of virus associated with the whitefly vector. PMID:27455309

  13. Compatibility of the insect pathogenic fungus Beauveria bassiana with neem against sweetpotato whitefly, Bemisia tabaci, on eggplant

    USDA-ARS?s Scientific Manuscript database

    A study on the compatibility of the entomopathogenic fungus Beauveria bassiana (Balsamo) Vuillemin (Ascomycota: Hypocreales) with neem was conducted against sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), on eggplant. Initially, three concentrations of B. bassiana (106, 1...

  14. Diversity and Distribution of Cryptic Species of the Bemisia tabaci (Hemiptera: Aleyrodidae) complex in Pakistan.

    PubMed

    Masood, Mariyam; Amin, Imran; Hassan, Ishtiaq; Mansoor, Shahid; Brown, Judith K; Briddon, Rob W

    2017-12-05

    Bemisia tabaci (Gennadius; Hempitera: Aleyrodidae) is considered to be a cryptic (sibling) species complex, the members of which exhibit morphological invariability while being genetically and behaviorally distinct. Members of the complex are agricultural pests that cause direct damage by feeding on plants, and indirectly by transmitting viruses that cause diseases leading to reduced crop yield and quality. In Pakistan, cotton leaf curl disease, caused by multiple begomovirus species, is the most economically important viral disease of cotton. In the study outlined here, the diversity and geographic distribution of B. tabaci cryptic species was investigated by analyzing a taxonomically informative fragment of the mitochondrial cytochrome c oxidase 1 gene (mtCOI-3'). The mtCOI-3' sequence was determined for 285 adult whiteflies and found to represent six cryptic species, the most numerous being Asia II-1 and Middle East Asia Minor 1 (MEAM-1), the later also referred to as the B-biotype, which was previously thought to be confined to Sindh province but herein, was also found to be present in the Punjab province. The endemic Asia I was restricted to Sindh province, while an individual in the Asia II-8 was identified in Pakistan for the first time. Also for the first time, samples were collected from northwestern Pakistan and Asia II-1 was identified. Results indicate that in Pakistan the overall diversity of B. tabaci cryptic species is high and, based on comparisons with findings from previous studies, the distribution is dynamic. © The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  15. Effect of drench application of flupyradifurone on Bemisia tabaci(MED whitefly) and Amblyseius swirskii, 2017

    USDA-ARS?s Scientific Manuscript database

    Bemisia tabaci is a polyphagous pest known to feed on over 900 plant taxa, and is an effective vector of more than 100 plant damaging viruses. Among different biotypes of this cryptic species complex, Middle East-Asia Minor 1 (MEAM1) and Mediterranean (MED)whitefly are the two most destructive membe...

  16. Climate change and Bemisia tabaci (Hemiptera: Aleyrodidae): Impacts of temperature and carbon dioxide on life history

    USDA-ARS?s Scientific Manuscript database

    Climate change is relevant to life around the globe. A rise in ambient temperature and CO2 may have various impacts on arthropods such as altered life cycles, modified reproductive patterns, and changes in distribution. The sweetpotato whitefly, Bemisia tabaci (Gennadius), is a global agricultural...

  17. Distribution of Bemisia tabaci (Hemiptera: Aleyrodidae) biotypes in North America after the Q invasion.

    PubMed

    McKenzie, Cindy L; Bethke, James A; Byrne, Frank J; Chamberlin, Joseph R; Dennehy, Timothy J; Dickey, Aaron M; Gilrein, Dan; Hall, Paula M; Ludwig, Scott; Oetting, Ronald D; Osborne, Lance S; Schmale, Lin; Shatters, Robert G

    2012-06-01

    After the 2004 discovery of the Bemisia tabaci (Gennadius) (Hemiptera Aleyrodidae) Q biotype in the United States, there was a vital need to determine the geographical and host distribution as well as its interaction with the resident B biotype because of its innate ability to rapidly develop high-level insecticide resistance that persists in the absence of exposure. As part of a coordinated country-wide effort, an extensive survey of B. tabaci biotypes was conducted in North America, with the cooperation of growers, industry, local, state, and federal agencies, to monitor the introduction and distribution of the Q biotype. The biotype status of submitted B. tabaci samples was determined either by polymerase chain reaction amplification and sequencing of a mitochondrial cytochrome oxidase I small subunit gene fragment and characterization of two biotype discriminating nuclear microsatellite markers or esterase zymogram analysis. Two hundred and eighty collections were sampled from the United States, Bermuda, Canada, and Mexico during January 2005 through December 2011. Host plants were split between ornamental plant and culinary herb (67%) and vegetable and field crop (33%) commodities. The New World biotype was detected on field-grown tomatoes (Solanum lycopersicum L.) in Mexico (two) and in commercial greenhouses in Texas (three) and represented 100% of these five collections. To our knowledge, the latter identification represents the first report of the New World biotype in the United States since its rapid displacement in the late 1980s after the introduction of biotype B. Seventy-one percent of all collections contained at least one biotype B individual, and 53% of all collections contained only biotype B whiteflies. Biotype Q was detected in 23 states in the United States, Canada (British Columbia and Ontario territories), Bermuda, and Mexico. Forty-five percent of all collections were found to contain biotype Q in samples from ornamentals, herbs and a single

  18. A Trichodorus (Triplonchida: Trichodoridae) Nematode from Thrips (Thysanoptera: Panchaetothripinae)

    PubMed Central

    Carta, L. K.; Skantar, A. M.

    2014-01-01

    A thrips insect Caliothrips sp. (Thysanoptera: Panchaetothripinae) from persimmon fruit (Ebenaceae: Diospyros sp.) from an unknown origin, possibly Asia, was intercepted in a passenger bag in November 2012 at the Peace Arch Border Crossing from Canada to Blaine, WA, by a USDA-APHIS-PPQ port inspector. Nematodes were attached to the abdomen of the female insect and sent to us in saline. Seven nematodes (five females, two males) were measured and these and others were processed for permanent slides. An adult female and a female juvenile were prepared for PCR. Morphologically these nematodes belonged to the Trichodorus sparsus group, and the 28S rDNA D2-D3 sequence showed greatest similarity to Trichodorus paragiennensis (94%) and T. giennensis (93%), with greatest morphological similarity to the latter species. Among other morphological differences, the innermost uterus width is wider than in related species. Trichodorus spp. are normally found in soil, so this is the first population seen in the atypical habitat of an insect. Morphological and molecular characteristics of Trichodorus sp. are presented, but a putative new species name is not currently advisable because of relatively poor condition of specimens. Ecological associations are also discussed. PMID:25276005

  19. Impact of drench application of cyantraniliprole on Bemisia tabaci (MED whitefly) and Amblyseius swirskii, 2016

    USDA-ARS?s Scientific Manuscript database

    Bemisia tabaci is a polyphagous pest known to feed on over 900 plant taxa, and is an effective vector of more than 100 plant damaging viruses. Among different biotypes of this cryptic species complex, MEAM1 and MED whitefly are the two most destructive members posing threats of several crops of econ...

  20. Effect of Eretmocerus eremicus and soil application of cyantraniliprole on Bemisia tabaci (MED whitefly), 2016

    USDA-ARS?s Scientific Manuscript database

    Bemisia tabaci is a polyphagous pest known to feed on over 900 plant taxa, and is an effective vector of more than 100 plant damaging viruses. Among different biotypes of this cryptic species complex, MEAM1 and MED whitefly are the two most destructive members posing threats to several crops of econ...

  1. Effect of soil application of cyantraniliprole on Bemisia tabaci (MED whitefly) and Amblyseius swirskii, 2016

    USDA-ARS?s Scientific Manuscript database

    Bemisia tabaci is a polyphagous pest known to feed upon over 900 plant taxa, and is an effective vector of more than 100 plant damaging viruses. Among different biotypes of this cryptic species complex, MEAM1 and MED whitefly are the two most destructive members posing threats of several crops of ec...

  2. Effect of foliar application of Xxpire on Bemisisa tabaci (MED whitefly) and Amblyseius swirskii, 2016

    USDA-ARS?s Scientific Manuscript database

    Bemisia tabaci is a polyphagous pest known to feed upon over 900 plant taxa, and is an effective vector of more than 100 plant damaging viruses. Among different biotypes of this cryptic species complex, MEAM1 and MED whitefly are the two most destructive members posing threats of several crops of ec...

  3. Effect of foliar application of pymetrozine on Bemisia tabaci (MED whitefly) and Amblyseius swirskii, 2016

    USDA-ARS?s Scientific Manuscript database

    Bemisia tabaci is a polyphagous pest known to feed upon over 900 plant taxa, and is an effective vector of more than 100 plant damaging viruses. Among different biotypes of this cryptic species complex, MEAM1 and MED whitefly are the two most destructive members posing threats of several crops of ec...

  4. Efficacy of foliar application of flupyradifurone on Bemisia tabaci (MED whitefly) and Amblyseius swirskii, 2017

    USDA-ARS?s Scientific Manuscript database

    Bemisia tabaci is a polyphagous pest known to feed upon over 900 plant taxa, and is an effective vector of more than 100 plant damaging viruses. Among different biotypes of this cryptic species complex, MEAM1 and MED whitefly are the two most destructive members posing threats of several crops of ec...

  5. Molecular and functional characterization of Bemisia tabaci aquaporins reveals the water channel diversity of hemipteran insects

    USDA-ARS?s Scientific Manuscript database

    The Middle East-Asia Minor 1 (MEAM1) whitefly, Bemisia tabaci (Gennadius) is an economically important pest of food, fiber, and ornamental crops. This pest has evolved a number of adaptations to overcome physiological challenges, including 1) the ability to regulate osmotic stress between gut lumen ...

  6. Susceptibility of Bemisia tabaci MEAM1 (Hemiptera: Aleyrodidae) to imidacloprid, thiamethoxam, dinotefuran and flupyradifurone in south Florida

    USDA-ARS?s Scientific Manuscript database

    Populations of Bemisa tabaci Middle East Asia Minor 1 (MEAM 1) were established from nineteen locations in south Florida, primarily from commercial tomato fields, and were tested using a cotton leaf petiole systemic uptake method for susceptibility to the nicotinic acetylcholine agonist insecticides...

  7. Only a minority of broad-range detoxification genes respond to a variety of phytotoxins in generalist Bemisia tabaci species

    PubMed Central

    Halon, Eyal; Eakteiman, Galit; Moshitzky, Pnina; Elbaz, Moshe; Alon, Michal; Pavlidi, Nena; Vontas, John; Morin, Shai

    2015-01-01

    Generalist insect can utilize two different modes for regulating their detoxification genes, the constitutive mode and the induced mode. Here, we used the Bemisia tabaci sibling species MEAM1 and MED, as a model system for studying constitutive and induced detoxification resistance and their associated tradeoffs. B. tabaci adults were allowed to feed through membranes for 24 h on diet containing only sucrose or sucrose with various phytotoxins. Quantitative real-time PCR analyses of 18 detoxification genes, indicated that relatively few transcripts were changed in both the MEAM1 and MED species, in response to the addition of phytotoxins to the diet. Induced transcription of detoxification genes only in the MED species, in response to the presence of indole-3-carbinol in the insect’s diet, was correlated with maintenance of reproductive performance in comparison to significant reduction in performance of the MEAM1 species. Three genes, COE2, CYP6-like 5 and BtGST2, responded to more than one compound and were highly transcribed in the insect gut. Furthermore, functional assays showed that the BtGST2 gene encodes a protein capable of interacting with both flavonoids and glucosinolates. In conclusion, several detoxification genes were identified that could potentially be involved in the adaptation of B. tabaci to its host plants. PMID:26655836

  8. O3-Induced Leaf Senescence in Tomato Plants Is Ethylene Signaling-Dependent and Enhances the Population Abundance of Bemisia tabaci

    PubMed Central

    Guo, Honggang; Sun, Yucheng; Yan, Hongyu; Li, Chuanyou; Ge, Feng

    2018-01-01

    Elevated ozone (O3) can alter the phenotypes of host plants particularly in induction of leaf senescence, but few reports examine the involvement of phytohormone in O3-induced changes in host phenotypes that influence the foraging quality for insects. Here, we used an ethylene (ET) receptor mutant Nr and its wild-type to determine the function of the ET signaling pathway in O3-induced leaf senescence, and bottom-up effects on the performance of Bemisia tabaci in field open-top chambers (OTCs). Our results showed that elevated O3 reduced photosynthetic efficiency and chlorophyll content and induced leaf senescence of plant regardless of plant genotype. Leaf senescence in Nr plants was alleviated relative to wild-type under elevated O3. Further analyses of foliar quality showed that elevated O3 had little effect on phytohormone-mediated defenses, but significantly increased the concentration of amino acids in two plant genotypes. Furthermore, Nr plants had lower amino acid content relative to wild-type under elevated O3. These results provided an explanation of O3-induced increase in abundance of B. tabaci. We concluded that O3-induced senescence of plant was ET signal-dependent, and positive effects of O3-induced leaf senescence on the performance of B. tabaci largely resulted from changes of nutritional quality of host plants. PMID:29946327

  9. Infection of the whitefly Bemisia tabaci with Rickettsia spp. alters its interactions with Tomato yellow leaf curl virus

    USDA-ARS?s Scientific Manuscript database

    Numerous animal and plant viruses are transmitted by arthropod vectors in a persistent, circulative manner. Tomato yellow leaf curl virus (TYLCV) is transmitted by the sweet potato whitefly Bemisia tabaci. Here we report that infection with Rickettsia spp., a facultative endosymbiont of whiteflies...

  10. Mitigating trans-boundary movement of Bemisia tabaci (Hemiptera: Aleyrodidae) on Mentha sp. by pre-shipping treaments of biopesticides

    USDA-ARS?s Scientific Manuscript database

    Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a major pest of several important crops including vegetables, cereals, fruits, and ornamentals grown worldwide. One important mode of its dispersal is through the trans-boundary movement of infested plant materials. In order to prevent the sprea...

  11. Is agriculture driving the diversification of the Bemisia tabaci species complex (Hemiptera: Sternorrhyncha: Aleyrodidae)?: Dating, diversification and biogeographic evidence revealed.

    PubMed

    Boykin, Laura M; Bell, Charles D; Evans, Gregory; Small, Ian; De Barro, Paul J

    2013-10-18

    Humans and insect herbivores are competing for the same food crops and have been for thousands of years. Despite considerable advances in crop pest management, losses due to insects remain considerable. The global homogenisation of agriculture has supported the range expansion of numerous insect pests and has been driven in part by human-assisted dispersal supported through rapid global trade and low-cost air passenger transport. One of these pests, is the whitefly, Bemisia tabaci, a cryptic species complex that contains some of the world's most damaging pests of agriculture. The complex shows considerable genetic diversity and strong phylogeographic relationships. One consequence of the considerable impact that members of the B. tabaci complex have on agriculture, is the view that human activity, particularly in relation to agricultural practices, such as use of insecticides, has driven the diversification found within the species complex. This has been particularly so in the case of two members of the complex, Middle East-Asia Minor 1 (MEAM1) and Mediterranean (MED), which have become globally distributed invasive species. An alternative hypothesis is that diversification is due to paleogeographic and paleoclimatological changes. The idea that human activity is driving speciation within the B. tabaci complex has never been tested, but the increased interest in fossil whiteflies and the growth in molecular data have enabled us to apply a relaxed molecular clock and so estimate divergence dates for the major lineages within the B. tabaci species complex. The divergence estimates do not support the view that human activity has been a major driver of diversification. Our analysis suggests that the major lineages within the complex arose approximately 60-30 mya and the highly invasive MED and MEAM1 split from the rest of the species complex around 12 mya well before the evolution of Homo sapiens and agriculture. Furthermore, the divergence dates coincide with a period

  12. Attraction of Three Mirid Predators to Tomato Infested by Both the Tomato Leaf Mining Moth Tuta absoluta and the Whitefly Bemisia tabaci.

    PubMed

    Silva, Diego B; Bueno, Vanda H P; Van Loon, Joop J A; Peñaflor, Maria Fernanda G V; Bento, José Maurício S; Van Lenteren, Joop C

    2018-01-01

    Plants emit volatile compounds in response to insect herbivory, which may play multiple roles as defensive compounds and mediators of interactions with other plants, microorganisms and animals. Herbivore-induced plant volatiles (HIPVs) may act as indirect plant defenses by attracting natural enemies of the attacking herbivore. We report here the first evidence of the attraction of three Neotropical mirid predators (Macrolophus basicornis, Engytatus varians and Campyloneuropsis infumatus) toward plants emitting volatiles induced upon feeding by two tomato pests, the leaf miner Tuta absoluta and the phloem feeder Bemisia tabaci, in olfactometer bioassays. Subsequently, we compared the composition of volatile blends emitted by insect-infested tomato plants by collecting headspace samples and analyzing them with GC-FID and GC-MS. Egg deposition by T. absoluta did not make tomato plants more attractive to the mirid predators than uninfested tomato plants. Macrolophus basicornis is attracted to tomato plants infested with either T. absoluta larvae or by a mixture of B. tabaci eggs, nymphs and adults. Engytatus varians and C. infumatus responded to volatile blends released by tomato plants infested with T. absoluta larvae over uninfested plants. Also, multiple herbivory by T. absoluta and B. tabaci did not increase the attraction of the mirids compared to infestation with T. absoluta alone. Terpenoids represented the most important class of compounds in the volatile blends and there were significant differences between the volatile blends emitted by tomato plants in response to attack by T. absoluta, B. tabaci, or by both insects. We, therefore, conclude that all three mirids use tomato plant volatiles to find T. absoluta larvae. Multiple herbivory did neither increase, nor decrease attraction of C. infumatus, E. varians and M. basicornis. By breeding for higher rates of emission of selected terpenes, increased attractiveness of tomato plants to natural enemies may

  13. Habitat-specific population structure in native western flower thrips Frankliniella occidentalis (Insecta, Thysanoptera).

    PubMed

    Brunner, P C; Frey, J E

    2010-04-01

    Invasions by pest organisms are among the main challenges for sustainable crop protection. They pose a serious threat to crop production by introducing a highly unpredictable element to existing crop protection strategies. The western flower thrips Frankliniella occidentalis (Insecta, Thysanoptera) managed to invade ornamental greenhouses worldwide within < 25 years. To shed light on possible genetic and/or ecological factors that may have been responsible for this invasion success, we studied the population genetic structure of western flower thrips in its native range in western North America. Analysis of nucleotide sequence variation and variation at microsatellite loci revealed the existence of two habitat-specific phylogenetic lineages (ecotypes) with allopatric distribution. One lineage is associated with hot/dry climates, the second lineage is restricted to cool/moist climates. We speculate that the ecological niche segregation found in this study may be among the key factors determining the invasion potential of western flower thrips.

  14. Silicon influence on resistance induction against Bemisia tabaci biotype B (Genn.) (Hemiptera: Aleyrodidae) and on vegetative development in two soybean cultivars.

    PubMed

    Ferreira, R S; Moraes, J C; Antunes, C S

    2011-01-01

    The potential of populations of Bemisia tabaci (Genn.) to become resistant to insecticides has stimulated research into alternative tactics of integrated pest management such as the induction of host-plant resistance. Recent data have shown that silicon can increase the degree of resistance of host plants to insect pests. Therefore the aim of our work was to study the effects of silicon application on the vegetative development of soybean plants and on the induction of resistance to the silverleaf whitefly, B. tabaci biotype B. We performed choice and no-choice tests of oviposition preference on two soybean cultivars, IAC-19 (moderately resistant to B. tabaci biotype B) and MONSOY-8001 (susceptible), with and without application of silicon. Silicon did not affect silverleaf whitefly oviposition preferences, but caused significant mortality in nymphs. Thus, silicon increased the degree of resistance to silverleaf whitefly. Silicon decreased the production of phenolic compounds, but did not affect lignin production. However, when applied to cultivar IAC-19, it increased the production of non-protein organic nitrogen. Silicon had no effect on the vegetative development of soybean plants, but it increased the degree of resistance to the silverleaf whitefly. We conclude that silicon applications combined with cultivar IAC-19 can significantly decrease silverleaf whitefly populations, having a positive impact both on the soybean plant and on the environment.

  15. Genome-wide piRNA profiles of virus transmitting whitefly Bemisia tabaci during feeding on TYLCV-infected tomato

    USDA-ARS?s Scientific Manuscript database

    Small RNAs (sRNAs) are 20-31 nucleotide (nt) non-coding regulatory elements commonly found in plants and animals, which are classified as short interfering RNA (siRNA), microRNA (miRNA) and Piwi-interacting RNA (piRNA). The whitefly Bemisia tabaci MEAM1 is a vector capable of transmitting many devas...

  16. The role of the whitefly, Bemisia tabaci (Gennadius), and farmer practices in the spread of cassava brown streak ipomoviruses.

    PubMed

    Maruthi, Midatharahally N; Jeremiah, Simon C; Mohammed, Ibrahim U; Legg, James P

    2017-12-01

    Cassava brown streak disease (CBSD) is arguably the most dangerous current threat to cassava, which is Africa's most important food security crop. CBSD is caused by two RNA viruses: Cassava brown streak virus (CBSV) and Ugandan cassava brown streak virus (UCBSV). The roles of the whitefly Bemisia tabaci (Gennadius) and farmer practices in the spread of CBSD were investigated in a set of field and laboratory experiments. The virus was acquired and transmitted by B. tabaci within a short time (5-10 min each for virus acquisition and inoculation), and was retained for up to 48 hr. Highest virus transmission (60%) was achieved using 20-25 suspected viruliferous whiteflies per plant that were given acquisition and inoculation periods of 24 and 48 hr, respectively. Experiments mimicking the agronomic practices of cassava leaf picking or the use of contaminated tools for making cassava stem cuttings did not show the transmission of CBSV or UCBSV. Screenhouse and field experiments in Tanzania showed that the spread of CBSD next to spreader rows was high, and that the rate of spread decreased with increasing distance from the source of inoculum. The disease spread in the field up to a maximum of 17 m in a cropping season. These results collectively confirm that CBSV and UCBSV are transmitted by B. tabaci semipersistently, but for only short distances in the field. This implies that spread over longer distances is due to movements of infected stem cuttings used for planting material. These findings have important implications for developing appropriate management strategies for CBSD.

  17. Role of the Insect Supervectors Bemisia tabaci and Frankliniella occidentalis in the Emergence and Global Spread of Plant Viruses.

    PubMed

    Gilbertson, Robert L; Batuman, Ozgur; Webster, Craig G; Adkins, Scott

    2015-11-01

    Emergence of insect-transmitted plant viruses over the past 10-20 years has been disproportionately driven by two so-called supervectors: the whitefly, Bemisia tabaci, and the Western flower thrips, Frankliniella occidentalis. High rates of reproduction and dispersal, extreme polyphagy, and development of insecticide resistance, together with human activities, have made these insects global pests. These supervectors transmit a diversity of plant viruses by different mechanisms and mediate virus emergence through local evolution, host shifts, mixed infections, and global spread. Associated virus evolution involves reassortment, recombination, and component capture. Emergence of B. tabaci-transmitted geminiviruses (begomoviruses), ipomoviruses, and torradoviruses has led to global disease outbreaks as well as multiple paradigm shifts. Similarly, F. occidentalis has mediated tospovirus host shifts and global dissemination and the emergence of pollen-transmitted ilarviruses. The plant virus-supervector interaction offers exciting opportunities for basic research and global implementation of generalized disease management strategies to reduce economic and environmental impacts.

  18. Fitness costs associated with infections of secondary endosymbionts in the cassava whitefly species Bemisia tabaci.

    PubMed

    Ghosh, Saptarshi; Bouvaine, Sophie; Richardson, Simon C W; Ghanim, Murad; Maruthi, M N

    2018-01-01

    We investigated the dual effects of bacterial infections and diseased cassava plants on the fitness and biology of the Bemisia tabaci infesting cassava in Africa. Isofemale B. tabaci colonies of sub-Saharan Africa 1-subgroup 3 (SSA1-SG3), infected with two secondary endosymbiotic bacteria Arsenophonus and Rickettsia (AR+) and those free of AR infections (AR-), were compared for fitness parameters on healthy and East African cassava mosaic virus -Uganda variant (EACMV-UG)-infected cassava plants. The whitefly fecundity and nymph development was not affected by bacterial infections or the infection of cassava by the virus. However, emergence of adults from nymphs was 50 and 17% higher by AR- on healthy and virus-infected plants, respectively, than AR+ flies. Development time of adults also was 10 days longer in AR+ than AR-. The whiteflies were further compared for acquisition and retention of EACMV-UG. Higher proportion of AR- acquired (91.8%) and retained (87.6%) the virus than AR+ (71.8, 61.2%, respectively). Similarly, the AR- flies retained higher quantities of virus (~ninefold more) than AR+. These results indicated that bacteria-free whiteflies were superior and better transmitters of EACMV-UG, as they had higher adult emergence, quicker life cycle and better virus retention abilities than those infected with bacteria.

  19. Complete mitochondrial DNA genome of Bemisia tabaci cryptic pest species complex Asia I (Hemiptera: Aleyrodidae).

    PubMed

    Tay, W T; Elfekih, S; Court, L; Gordon, K H; De Barro, P J

    2016-01-01

    The complete length of the Asia I member of the Bemisia tabaci species complex mitochondrial DNA genome (mitogenome) is 15,210 bp (GenBank accession no. KJ778614) with an A-T biased nucleotide composition (A: 32.7%; T: 42.4%; G: 14.0%; C: 10.8%). The mitogenome consists of 13 protein-coding genes (PCGs), 22 transfer RNAs (tRNAs), 2 ribosomal RNA (rRNAs) and a 467 bp putative control region which also includes the A+T rich repeat region. All PCGs have an ATA (n = 8) or ATG (n = 5) start codon. Gene synteny of Asia I is overall similar to B. afer and two other members of the B. tabaci species complex Mediterranean and New World 1, and contains the tRNA-Ser2 located between the Cytb and ND1 genes found in Mediterranean and New World 1, but which is absent in B. afer. The orientation of the tRNA-Arg in Asia I is on the "plus" strand and differed from Mediterranean which is found on the "minus" strand. The Asia I mitogenome size is currently ranked the second smallest after B. afer (14,968 bp) followed by New World 1 (15,322 bp) and Mediterranean (15,632 bp).

  20. Postharvest Irradiation Treatment for Quarantine Control of Western Flower Thrips (Thysanoptera: Thripidae).

    PubMed

    Nicholas, Adrian H; Follett, Peter A

    2018-04-05

    The western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), is an important pest of fresh horticultural produce and as such is considered a biosecurity risk in many countries from which it is absent. Information is needed on the radiation tolerance of important surface pests of quarantine importance such as F. occidentalis so that phytosanitary irradiation treatments for exported fresh commodities can be lowered to below the 400 Gy generic treatment currently approved for most insects in the United States and Australia. Lowering the dose will help minimize any product quality problems, reduce costs, and shorten treatment time. In large-scale confirmatory trials conducted in two independent laboratories in Hawaii and Australia, a dose of 250 Gy (measured doses 222-279 Gy) applied to adult F. occidentalis on green beans resulted in no reproduction in 5,050 treated individuals. At 250 Gy, the effective dose is significantly below the 400 Gy generic dose, demonstrating that irradiation at this lowered level is an effective method for the disinfestation of F. occidentalis from fresh horticultural produce.

  1. Biological Invasions of Geminiviruses: Case Study of TYLCV and Bemisia tabaci in Reunion Island

    PubMed Central

    Péréfarres, Frédéric; Thierry, Magali; Becker, Nathalie; Lefeuvre, Pierre; Reynaud, Bernard; Delatte, Hélène; Lett, Jean-Michel

    2012-01-01

    In the last 20 years, molecular ecology approaches have proven to be extremely useful to identify and assess factors associated with viral emerging diseases, particularly in economically and socially important tropical crops such as maize (maize streak disease) and cassava (cassava mosaic disease). Molecular ecology approaches were applied in Reunion Island to analyze the epidemic of tomato yellow leaf curl disease, which has been affecting the island since the end of the 1990s. Before the invasive biotype B (currently known as Middle East-Asia Minor 1 cryptic species) of Bemisia tabaci spread across the world, Reunion Island (South West Indian Ocean) only hosted an indigenous biotype of B. tabaci, Ms (currently known as Indian Ocean cryptic species). Wild hybrids between invasive and indigenous species were subsequently characterized over multiple generations. Endosymbiont analysis of the hybrid population indicated that matings were non-random. Similarly, while no indigenous begomoviruses have ever been reported on Reunion Island, the two main strains of one of the most damaging and emerging plant viruses in the world, the Mild and Israel strains of the Tomato yellow leaf curl virus (TYLCV-Mld and TYLCV-IL), were introduced in 1997 and 2004 respectively. While these introductions extensively modified the agricultural landscape of Reunion Island, they also provided an invaluable opportunity to study the ecological and genetic mechanisms involved in biological invasion and competition. PMID:23235470

  2. Challenges with managing insecticide resistance in agricultural pests, exemplisfied by the whitefly Bemisia tabaci

    PubMed Central

    Denholm, I.

    1998-01-01

    For many key agricultural pests, successful management of insecticide resistance depends not only on modifying the way that insecticides are deployed, but also on reducing the total number of treatments applied. Both approaches benefit from a knowledge of the biological characteristics of pests that promote or may retard the development of resistance. For the whitefly Bemisia tabaci (Gennadius), these factors include a haplodiploid breeding system that encourages the rapid selection and fixation of resistance genes, its breeding cycle on a succession of treated or untreated hosts, and its occurrence on and dispersal from high-value crops in greenhouses and glasshouses. These factors, in conjunction with often intensive insecticide use, have led to severe and widespread resistance that now affects several novel as well as conventional control agents. Resistance-management strategies implemented on cotton in Israel, and subsequently in south-western USA, have nonetheless so far succeeded in arresting the resistance treadmill in B. tabaci through a combination of increased chemical diversity, voluntary or mandatory restrictions on the use of key insecticides, and careful integration of chemical control with other pest-management options. In both countries, the most significant achievement has been a dramatic reduction in the number of insecticide treatments applied against whiteflies on cotton, increasing the prospect of sustained use of existing and future insecticides.

  3. Genome sequencing and analysis of the whitefly (Bemisia tabaci) MEAM1, one of the most important vectors for plant viruses

    USDA-ARS?s Scientific Manuscript database

    Among whiteflies, the Bemisia tabaci (Hemiptera: Aleyrodidae) species complex is particularly important because of its ability to transmit hundreds of plant viruses, resulting in the loss of billions of U.S. dollars on agronomically important crops such as tomato, cucurbits, cassava, and cotton worl...

  4. Transcriptome analysis reveals a comprehensive insect resistance response mechanism in cotton to infestation by the phloem feeding insect Bemisia tabaci (whitefly)

    USDA-ARS?s Scientific Manuscript database

    The whitefly (Bemisia tabaci) causes tremendous damage to cotton production worldwide. However, very limited information is available about how plants perceive and defend themselves from this destructive pest. In this study, the transcriptomics differences between two cotton cultivars that exhibit e...

  5. Status of Resistance of Bemisia tabaci (Hemiptera: Aleyrodidae) to Neonicotinoids in Iran and Detoxification by Cytochrome P450-Dependent Monooxygenases.

    PubMed

    Basij, M; Talebi, K; Ghadamyari, M; Hosseininaveh, V; Salami, S A

    2017-02-01

    Nine Bemisia tabaci (Gennadius) populations were collected from different regions of Iran. In all nine populations, only one biotype (B biotype) was detected. Susceptibilities of these populations to imidacloprid and acetamiprid were assayed. The lethal concentration 50 values (LC 50 ) for different populations showed a significant discrepancy in the susceptibility of B. tabaci to imidacloprid (3.76 to 772.06 mg l -1 ) and acetamiprid (4.96 to 865 mg l -1 ). The resistance ratio of the populations ranged from 9.72 to 205.20 for imidacloprid and 6.38 to 174.57 for acetamiprid. The synergistic effects of piperonylbutoxide (PBO) and S,S,S-tributylphosphorotrithioate (DEF) were evaluated for the susceptible (RF) and resistant (JR) populations for the determination of the involvement of cytochrome P450-dependent monooxygenase and carboxylesterase, respectively, in their resistance mechanisms. The results showed that PBO overcame the resistance of the JR population to both imidacloprid and acetamiprid, with synergistic ratios of 72.7 and 106.9, respectively. Carboxylesterase, glutathione S-transferase and cytochrome P450-dependent monooxygenase were studied biochemically, for the purpose of measuring the activity of the metabolizing enzymes in order to determine which enzymes are directly involved in neonicotinoid resistance. There was an increase in the activity of cytochrome P450-dependent monooxygenase up to 17-fold in the resistant JR population (RR = 205.20). The most plausible activity of cytochrome P450-dependent monooxygenase correlated with the resistances of imidacloprid and acetamiprid, and this suggests that cytochrome P450-dependent monooxygenase is the only enzyme system responsible for neonicotinoid resistance in the nine populations of B. tabaci.

  6. Transcriptome analysis of Bemisia tabaci during tomato yellow leaf curl virus acquisition and ribonucleic acid interference to manage whitefly-transmitted viruses

    USDA-ARS?s Scientific Manuscript database

    Over 300 viruses are transmitted by the whitefly, Bemisia tabaci, with 90% of them belonging to the genus, Begomovirus. Begomoviruses are obligately transmitted by whiteflies to a wide range of agriculture crops, resulting in billions of dollars lost annually, while jeopardizing food security worldw...

  7. Transcriptome changes occurred in the whitefly, B. tabaci MEAM1 in response to feeding on melon infected with the crinivirus, CYSDV

    USDA-ARS?s Scientific Manuscript database

    Cucurbit yellow stunting disorder virus (CYSDV), a crinivirus transmitted by the whitefly, B. tabaci, causes widespread losses in melon in many parts of the world. The virus emerged in the southwestern United States (Arizona and California) and western Mexico in 2006 and rapidly became established ...

  8. Establishment of papaya banker plant system for Parasitoid, Encarsia sophia (Hymenoptera: Aphilidae) against Bemisia tabaci (Hemiptera: Aleyrodidae) in greenhouse tomato production

    USDA-ARS?s Scientific Manuscript database

    The silverleaf whitefly, Bemisia tabaci biotype B (Gennadius) (Hemiptera:Aleyrodidae), is a key pest of tomato (Solanum lycopersicum L.) and other vegetable crops worldwide. To combat this pest, a non-crop banker plant system was evaluated that employs a parasitoid, Encarsia sophia (Girault & Dodd) ...

  9. Plastic cup traps equipped with light-emitting diodes for monitoring adult Bemisia tabaci (Homoptera: Aleyrodidae).

    PubMed

    Chu, Chang-Chi; Jackson, Charles G; Alexander, Patrick J; Karut, Kamil; Henneberry, Thomas J

    2003-06-01

    Equipping the standard plastic cup trap, also known as the CC trap, with lime-green light-emitting diodes (LED-plastic cup trap) increased its efficacy for catching Bemisia tabaci by 100%. Few Eretmocerus eremicus Rose and Zolnerowich and Encarsia formosa Gahan were caught in LED-plastic cup traps. The LED-plastic cup traps are less expensive than yellow sticky card traps for monitoring adult whiteflies in greenhouse crop production systems and are more compatible with whitefly parasitoids releases for Bemisia nymph control.

  10. [Phagodeterrent activity of the plants Tithonia diversifolia and Montanoa hibiscifolia (Asteraceae) on adults of the pest insect Bemisia tabaci (Homoptera: Aleyrodidae)].

    PubMed

    Bagnarello, Gina; Hilje, Luko; Bagnarello, Vanessa; Cartín, Victor; Calvo, Marco

    2009-12-01

    Bemisia tabaci (Gennadius) is a polyphagous, cosmopolitan and worldwide relevant pest, mainly acting as a virus vector on many crops. A sound preventive approach to deal with it would be the application of repellent or deterrent substances hopefully present in tropical plants, which in turn may contribute to take advantage of the remarkable rich Mesoamerican biodiversity. Therefore, extracts of two wild plants belonging to family Asteraceae, titonia (Tithonia diversifolia) and "tora" (Montanoa hibiscifolia), were tested for phagodeterrence to B. tabaci adults. The crude leaf extract of each one, as well as four fractions thereof (hexane, dichlorometane, ethyl acetate, and methanol) were tested under greenhouse conditions; in addition, the extracts were submitted to a phytochemical screening to determine possible metabolites causing phagodeterrence. Both restricted-choice and unrestricted-choice experiments were conducted. In the former ones, each fraction was tested at four doses (0.1, 0.5, 1.0 and 1.5% v/v), which were compared with four control treatments: distilled water, endosulfan, an agricultural oil (Aceite Agricola 81 SC), and the emulsifier Citowett. Tomato plants were sprayed and placed inside sleeve cages, where 50 B. tabaci adults were released. The criterion to appraise phagodeterrence was the number of landed adults on plants at 48h. For the unrestricted-choice experiments, only the two highest doses (1.0 and 1.5%) of the crude extracts of each species were tested, and compared to distilled water and the agricultural oil. The titonia and "tora" crude extracts caused phagodeterrence, and for both plant species the methanol fraction stood out. Results suggest that metabolites causing phagodeterrence are several sesquiterpenic lactones, polyphenolic compounds (flavonoids and tannins) and saponins.

  11. Resistance of Collard Green Genotypes to Bemisia tabaci Biotype B: Characterization of Antixenosis.

    PubMed

    Domingos, G M; Baldin, E L L; Canassa, V F; Silva, I F; Lourenção, A L

    2018-08-01

    Bemisia tabaci (Genn.) biotype B (Hemiptera: Aleyrodidae) is an important pest of vegetable crops, including collard greens Brassica oleracea var. acephala (Brassicaceae). The use of resistant genotypes is an interesting option to reduce insect populations and can be used as an important tool for integrated pest management (IPM). This study evaluated 32 genotypes of collard greens against the attack of silver leaf whitefly, with the aim to characterize antixenosis. Initially, a multiple-choice trial was conducted using all genotypes, in which the adult attractiveness was assessed on two leaves per genotype at 24 and 48 h after infestation. After 48 h, one leaf of each genotype was randomly selected for the determination of the number of eggs per square centimeter. From the results of the multiple-choice trial, 13 genotypes were selected for a no-choice oviposition test, following the same method of the previous test. Colorimetric analyses were also performed to establish possible correlations between leaf color and insect colonization. Genotypes HS-20, OE, and VA were less attractive, demonstrating antixenosis. Genotypes LG, VE, J, MG, MOP, HS-20, VA, and MT had less oviposition in the multiple-choice test, which indicated expression of antixenosis. In the no-choice test, genotypes VE, P1C, CCB, RI-919, H, and J had less oviposition, which also characterized antixenosis. Therefore, genotypes VE and J showed the highest resistance stability because both had less oviposition in both test modalities. Thus, the resistance to B. tabaci biotype B indicates the genotypes HS-20, OE, VA, VE, and J are promising for use in breeding programs to develop resistance to whitefly.

  12. Sampling techniques for thrips (Thysanoptera: Thripidae) in preflowering tomato.

    PubMed

    Joost, P Houston; Riley, David G

    2004-08-01

    Sampling techniques for thrips (Thysanoptera: Thripidae) were compared in preflowering tomato plants at the Coastal Plain Experiment Station in Tifton, GA, in 2000 and 2003, to determine the most effective method of determining abundance of thrips on tomato foliage early in the growing season. Three relative sampling techniques, including a standard insect aspirator, a 946-ml beat cup, and an insect vacuum device, were compared for accuracy to an absolute method and to themselves for precision and efficiency of sampling thrips. Thrips counts of all relative sampling methods were highly correlated (R > 0.92) to the absolute method. The aspirator method was the most accurate compared with the absolute sample according to regression analysis in 2000. In 2003, all sampling methods were considered accurate according to Dunnett's test, but thrips numbers were lower and sample variation was greater than in 2000. In 2000, the beat cup method had the lowest relative variation (RV) or best precision, at 1 and 8 d after transplant (DAT). Only the beat cup method had RV values <25 for all sampling dates. In 2003, the beat cup method had the lowest RV value at 15 and 21 DAT. The beat cup method also was the most efficient method for all sample dates in both years. Frankliniella fusca (Pergande) was the most abundant thrips species on the foliage of preflowering tomato in both years of study at this location. Overall, the best thrips sampling technique tested was the beat cup method in terms of precision and sampling efficiency.

  13. Susceptibility of MED-Q1 and MED-Q3 Biotypes of Bemisia tabaci (Hemiptera: Aleyrodidae) Populations to Essential and Seed Oils.

    PubMed

    Samuel Fogné, Drabo; Olivier, Gnankine; Bassolé, Imael H N; Nébié, Roger Charles; Laurence, Mouton

    2017-06-01

    Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a major pest of many agricultural and ornamental crops in tropical and subtropical regions causing damages that result in important economic losses. Insecticides are commonly used in greenhouses or fields to control B. tabaci populations leading to rapid evolution of resistance that render treatments inefficient. Therefore, and for environmental and human health concerns, other approaches must be developed for this pest management. In the present study, we compare, using the leaf dip method, the toxicity of three essential oils (Cymbopogon citratus, Ocimum americanum, and Hyptis spicigera) and three seed oils (Lannea microcarpa, Lannea acida, and Carapa procera) with three chemical insecticides (acetamiprid, deltamethrin, and chlorpyrifos-ethyl) on adults. Two B. tabaci biotypes (MED-Q1 and MED-Q3) belonging to the Mediterranean species and collected in Burkina Faso were used. Essential oils were analyzed by gas chromatography-mass spectrometry and gas chromatography-flame ionization detector. We showed that these two biotypes have different levels of resistance to the three insecticides, MED-Q3 being more sensitive than MED-Q1. Moreover, they differ in the frequency of resistance alleles to insecticides, especially for organophosphates, as these alleles are almost fixed in MED-Q1. On the other hand, the two biotypes prove to be more susceptible to the plant extracts than to insecticides except for chlorpyrifos-ethyl, with essential oils that showed the highest insecticidal activities. Monoterpenes content were the most abundant and showed the highest insecticidal activities. Our results indicated that essential oils, but also seed oils, have the potential to constitute an alternative strategy of pest management. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  14. Lethal and Sublethal Effects of Clothianidin on the Development and Reproduction of Bemisia tabaci (Hemiptera: Aleyrodidae) MED and MEAM1

    PubMed Central

    Fang, Yong; Wang, Jinda; Luo, Chen; Wang, Ran

    2018-01-01

    Abstract The Bemisia tabaci (Gennadius) cryptic species complex includes important crop pests, and among them, the cryptic species Mediterranean (MED) and Middle East-Asia Minor 1 (MEAM1) cause substantial crop losses in China. The second-generation neonicotinoid clothianidin acts as an agonist of the nicotinic acetylcholine receptor in the insect nervous system and has both stomach and contact activity. In this study, the toxicity of clothianidin and five other insecticides to MED and MEAM1 was examined. The sublethal effects of clothianidin on the development and reproduction of MED and MEAM1 were also investigated. Among the six insecticides tested, clothianidin showed toxicities to both MED and MEAM1 adults with LC50 values of 5.23 and 5.18 mg/liter, respectively. The sublethal effects of clothianidin were assessed by treating MED and MEAM1 adults with the LC25 of 1.58 and 1.13 mg/liter, respectively. The LC25 treatments accelerated the development of the F1 generation but reduced survival and fecundity of both species. Our results indicate that clothianidin could be useful for the management of B. tabaci MED and MEAM1. PMID:29718499

  15. The Trouble with MEAM2: Implications of Pseudogenes on Species Delimitation in the Globally Invasive Bemisia tabaci (Hemiptera: Aleyrodidae) Cryptic Species Complex.

    PubMed

    Tay, Wee Tek; Elfekih, Samia; Court, Leon N; Gordon, Karl H J; Delatte, Hélène; De Barro, Paul J

    2017-10-01

    Molecular species identification using suboptimal PCR primers can over-estimate species diversity due to coamplification of nuclear mitochondrial (NUMT) DNA/pseudogenes. For the agriculturally important whitefly Bemisia tabaci cryptic pest species complex, species identification depends primarily on characterization of the mitochondrial DNA cytochrome oxidase I (mtDNA COI) gene. The lack of robust PCR primers for the mtDNA COI gene can undermine correct species identification which in turn compromises management strategies. This problem is identified in the B. tabaci Africa/Middle East/Asia Minor clade which comprises the globally invasive Mediterranean (MED) and Middle East Asia Minor I (MEAM1) species, Middle East Asia Minor 2 (MEAM2), and the Indian Ocean (IO) species. Initially identified from the Indian Ocean island of Réunion, MEAM2 has since been reported from Japan, Peru, Turkey and Iraq. We identified MEAM2 individuals from a Peruvian population via Sanger sequencing of the mtDNA COI gene. In attempting to characterize the MEAM2 mitogenome, we instead characterized mitogenomes of MEAM1. We also report on the mitogenomes of MED, AUS, and IO thereby increasing genomic resources for members of this complex. Gene synteny (i.e., same gene composition and orientation) was observed with published B. tabaci cryptic species mitogenomes. Pseudogene fragments matching MEAM2 partial mtDNA COI gene exhibited low frequency single nucleotide polymorphisms that matched low copy number DNA fragments (<3%) of MEAM1 genomes, whereas presence of internal stop codons, loss of expected stop codons and poor primer annealing sites, all suggested MEAM2 as a pseudogene artifact and so not a real species. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  16. The draft genome of whitefly Bemisia tabaci MEAM1, a global crop pest, provides novel insights into virus transmission, host adaptation, and insecticide resistance

    USDA-ARS?s Scientific Manuscript database

    Whiteflies are among the most important agricultural pests. They have a broad range of host plants and exceptional ability to transmit a large number of plant viruses, and can rapidly evolve insecticide resistance. Here we present a high-quality draft genome of the whitefly, Bemisia tabaci. Comparat...

  17. Biochemical evaluation of interactions between synergistic molecules and phase I enzymes involved in insecticide resistance in B- and Q-type Bemisia tabaci (Hemiptera: Aleyrodidae).

    PubMed

    Panini, Michela; Tozzi, Francesco; Zimmer, Christoph T; Bass, Chris; Field, Linda; Borzatta, Valerio; Mazzoni, Emanuele; Moores, Graham

    2017-09-01

    Metabolic resistance is an important consideration in the whitefly Bemisia tabaci, where an esterase-based mechanism has been attributed to pyrethroid resistance and over-expression of the cytochrome P450, CYP6CM1, has been correlated to resistance to imidacloprid and other neonicotinoids. In vitro interactions between putative synergists and CYP6CM1, B and Q-type esterases were investigated, and structure-activity relationship analyses allowed the identification of chemical structures capable of acting as inhibitors of esterase and oxidase activities. Specifically, methylenedioxyphenyl (MDP) moieties with a polyether chain were preferable for optimum inhibition of B-type esterase, whilst corresponding dihydrobenzofuran structures were potent for the Q-esterase variation. Potent inhibition of CYP6CM1 resulted from structures which contained an alkynyl chain with a terminal methyl group. Synergist candidates could be considered for field control of B. tabaci, especially to abrogate neonicotinoid resistance. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  18. Distribution and ecology of Frankliniella occidentalis (Thysanoptera: Thripidae) bacterial symbionts.

    PubMed

    Chanbusarakum, Lisa J; Ullman, Diane E

    2009-08-01

    Bacterial populations in Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) collected in diverse California environments consisted of two bacterial symbionts: BFo-1 and BFo-2 (B = bacteria, Fo = Frankliniella occidentalis, numbers reflect different types). Dual infections of BFo-1 and BFo-2 were found in 50% of the thrips, 18% had neither bacterium, and 24 and 8% were infected solely with BFo-1 and BFo-2, respectively. No other bacteria consistently infected F. occidentalis. Dual infections occurred more often in male thrips and in thrips of both sexes from southern mountain and valley sites. As average collection year or month minimum temperature decreased, infections of BFo-1, alone or in dual infections, increased significantly. As yearly precipitation increased, infection with BFo-1 alone also increased. F. occidentalis color morphology did not affect bacterial infection. BFo-1 created weak biofilms at 25 and 32 degrees C; BFo-2 made strong biofilms at 25 degrees C and no biofilms at 32 degrees C. When the bacteria were grown in culture together, weak biofilms formed at both temperatures studied, although there was no way to determine what each bacterium contributed to the biofilm. BFo-1 and BFo-2 grew at similar rates at 25 and 30 degrees C. Our data show BFo-1 and BFo-2 occur in natural populations of F. occidentalis and support the hypothesis BFo have a symbiotic relationship with F. occidentalis. Regional differences in bacterial prevalence suggest bacterial infection is associated with environmental conditions, and altitude, temperature, and precipitation may be important factors.

  19. Comparative transcriptome analysis in Bemisia tabaci in response to tomato yellow leaf curl virus and development of ribonucleic acid interference to manage whitefly-transmitted viruses

    USDA-ARS?s Scientific Manuscript database

    The whitefly, Bemisia tabaci transmits over 300 plant viruses, with the majority of them belonging to the Begomovirus genus. Begomoviruses are obligately transmitted to a wide range of agriculture crops, resulting in the loss of billions of dollars annually, while jeopardizing food security worldwid...

  20. Reproduction of the whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) B biotype in maize fields (Zea mays L.) in Brazil.

    PubMed

    Quintela, Eliane D; Abreu, Aluana G; Lima, Julyana F Dos S; Mascarin, Gabriel M; Santos, Jardel B Dos; Brown, Judith K

    2016-11-01

    Bemisia tabaci (Genn.) (Hemiptera: Aleyrodidae) was observed to have completed its reproductive cycle from the egg to the adult on maize (Zea mays L.). Field and screenhouse studies were carried out to investigate the durability of this putative and unprecedented adaptation to a grass host. Analysis of the mitochondrial COI gene sequence identified the maize-associated B. tabaci as the exotic B biotype (major clade North Africa-Mediterranean-Middle East). Results showed that whiteflies migrated from soybean crops and successfully established in maize plants. Females exhibited a preference for oviposition primarily on the first and second leaves of maize, but were also able to colonise developing leaves. A high, natural infestation on maize (193.3 individuals, all developmental stages) was observed within a 7.1 cm 2 designated 'observation area'. Whiteflies collected from naturally infested maize leaves and allowed to oviposit on maize seedlings grown in a screenhouse developed from egg to adulthood in 28.6 ± 0.2 days. This is the first report of the B biotype completing its development on maize plants. This surprising anomaly indicates that the B biotype is capable of adapting to monocotyledonous host plants, and importantly, broadens the host range to include at least one species in the Poaceae. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  1. Insecticide resistance in Bemisia tabaci Gennadius (Homoptera: Aleyrodidae) and Anopheles gambiae Giles (Diptera: Culicidae) could compromise the sustainability of malaria vector control strategies in West Africa.

    PubMed

    Gnankiné, Olivier; Bassolé, Imael H N; Chandre, Fabrice; Glitho, Isabelle; Akogbeto, Martin; Dabiré, Roch K; Martin, Thibaud

    2013-10-01

    Insecticides from the organophosphate (OP) and pyrethroid (PY) chemical families, have respectively, been in use for 50 and 30 years in West Africa, mainly against agricultural pests, but also against vectors of human disease. The selection pressure, with practically the same molecules year after year (mainly on cotton), has caused insecticide resistance in pest populations such as Bemisia tabaci, vector of harmful phytoviruses on vegetables. The evolution toward insecticide resistance in malaria vectors such as Anopheles gambiae sensus lato (s.l.) is probably related to the current use of these insecticides in agriculture. Thus, successful pest and vector control in West Africa requires an investigation of insect susceptibility, in relation to the identification of species and sub species, such as molecular forms or biotypes. Identification of knock down resistance (kdr) and acetylcholinesterase gene (Ace1) mutations modifying insecticide targets in individual insects and measure of enzymes activity typically involved in insecticide metabolism (oxidase, esterase and glutathion-S-transferase) are indispensable in understanding the mechanisms of resistance. Insecticide resistance is a good example in which genotype-phenotype links have been made successfully. Insecticides used in agriculture continue to select new resistant populations of B. tabaci that could be from different biotype vectors of plant viruses. As well, the evolution of insecticide resistance in An. gambiae threatens the management of malaria vectors in West Africa. It raises the question of priority in the use of insecticides in health and/or agriculture, and more generally, the question of sustainability of crop protection and vector control strategies in the region. Here, we review the susceptibility tests, biochemical and molecular assays data for B. tabaci, a major pest in cotton and vegetable crops, and An. gambiae, main vector of malaria. The data reviewed was collected in Benin and Burkina

  2. Further insight into reproductive incompatibility between putative cryptic species of the Bemisia tabaci whitefly complex.

    PubMed

    Qin, Li; Pan, Li-Long; Liu, Shu-Sheng

    2016-04-01

    The whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), with its global distribution and extensive genetic diversity, is now known to be a complex of over 35 cryptic species. However, a satisfactory resolution of the systematics of this species complex is yet to be achieved. Here, we designed experiments to examine reproductive compatibility among species with different levels of mitochondrial cytochrome oxidase I (mtCOI) divergence. The data show that putative species with mtCOI divergence of >8% between them consistently exhibited complete reproductive isolation. However, two of the putative species, Asia II 9 and Asia II 3, with mtCOI divergence of 4.47% between them, exhibited near complete reproductive compatibility in one direction of their cross, and partial reproductive compatibility in the other direction. Together with some recent reports on this topic from the literature, our data indicates that, while divergence in the mtCOI sequences provides a valid molecular marker for species delimitation in most clades, more genetic markers and more sophisticated molecular phylogeny will be required to achieve adequate delimitation of all species in this whitefly complex. While many attempts have been made to examine the reproductive compatibility among genetic groups of the B. tabaci complex, our study represents the first effort to conduct crossing experiments with putative species that were chosen with considerations of their genetic divergence. In light of the new data, we discuss the best strategy and protocols to conduct further molecular phylogenetic analysis and crossing trials, in order to reveal the overall pattern of reproductive incompatibility among species of this whitefly complex. © 2015 Institute of Zoology, Chinese Academy of Sciences.

  3. Gene Expression Profiling in the Thiamethoxam Resistant and Susceptible B-biotype Sweetpotato Whitefly, Bemisia tabaci

    PubMed Central

    Xie, Wen; Yang, Xin; Wang, Shao-Ii; Wu, Qing-jun; Yang, Ni-na; Li, Ru-mei; Jiao, Xiaoguo; Pan, Hui-peng; Liu, Bai-ming; Feng, Yun-tao; Xu, Bao-yun; Zhou, Xu-guo; Zhang, You-jun

    2012-01-01

    Thiamethoxam has been used as a major insecticide to control the B-biotype sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae). Due to its excessive use, a high level of resistance to thiamethoxam has developed worldwide over the past several years. To better understand the molecular mechanisms underlying this resistance in B. tabaci, gene profiles between the thiamethoxam-resistant and thiamethoxam-susceptible strains were investigated using the suppression subtractive hybridization (SSH) library approach. A total of 72 and 52 upand down-regulated genes were obtained from the forward and reverse SSH libraries, respectively. These expressed sequence tags (ESTs) belong to several functional categories based on their gene ontology annotation. Some categories such as cell communication, response to abiotic stimulus, lipid particle, and nuclear envelope were identified only in the forward library of thiamethoxam-resistant strains. In contrast, categories such as behavior, cell proliferation, nutrient reservoir activity, sequence-specific DNA binding transcription factor activity, and signal transducer activity were identified solely in the reverse library. To study the validity of the SSH method, 16 differentially expressed genes from both forward and reverse SSH libraries were selected randomly for further analyses using quantitative realtime PCR (qRT-PCR). The qRT-PCR results were fairly consistent with the SSH results; however, only 50% of the genes showed significantly different expression profiles between the thiamethoxam-resistant and thiamethoxam-susceptible whiteflies. Among these genes, a putative NAD-dependent methanol dehydrogenase was substantially over-expressed in the thiamethoxamresistant adults compared to their susceptible counterparts. The distributed profiles show that it was highly expressed during the egg stage, and was most abundant in the abdomen of adult females. PMID:22957505

  4. The invasive MED/Q Bemisia tabaci genome: a tale of gene loss and gene gain.

    PubMed

    Xie, Wen; Yang, Xin; Chen, Chunhai; Yang, Zezhong; Guo, Litao; Wang, Dan; Huang, Jinqun; Zhang, Hailin; Wen, Yanan; Zhao, Jinyang; Wu, Qingjun; Wang, Shaoli; Coates, Brad S; Zhou, Xuguo; Zhang, Youjun

    2018-01-22

    Sweetpotato whitefly, Bemisia tabaci MED/Q and MEAM1/B, are two economically important invasive species that cause considerable damages to agriculture crops through direct feeding and indirect vectoring of plant pathogens. Recently, a draft genome of B. tabaci MED/Q has been assembled. In this study, we focus on the genomic comparison between MED/Q and MEAM1/B, with a special interest in MED/Q's genomic signatures that may contribute to the highly invasive nature of this emerging insect pest. The genomes of both species share similarity in syntenic blocks, but have significant divergence in the gene coding sequence. Expansion of cytochrome P450 monooxygenases and UDP glycosyltransferases in MED/Q and MEAM1/B genome is functionally validated for mediating insecticide resistance in MED/Q using in vivo RNAi. The amino acid biosynthesis pathways in MED/Q genome are partitioned among the host and endosymbiont genomes in a manner distinct from other hemipterans. Evidence of horizontal gene transfer to the host genome may explain their obligate relationship. Putative loss-of-function in the immune deficiency-signaling pathway due to the gene loss is a shared ancestral trait among hemipteran insects. The expansion of detoxification genes families, such as P450s, may contribute to the development of insecticide resistance traits and a broad host range in MED/Q and MEAM1/B, and facilitate species' invasions into intensively managed cropping systems. Numerical and compositional changes in multiple gene families (gene loss and gene gain) in the MED/Q genome sets a foundation for future hypothesis testing that will advance our understanding of adaptation, viral transmission, symbiosis, and plant-insect-pathogen tritrophic interactions.

  5. Pre shipping dip treatments using soap, natural oils, and Isaria fumosorosea: potential biopesticides for mitigating the spread of whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) invasive insects on ornamental plants

    USDA-ARS?s Scientific Manuscript database

    The whitefly Bemisia tabaci (Hemiptera: Aleyodidae) is an invasive insect pest affecting different crops including vegetables, fruits, cereals, and ornamentals. The efficacy of some products such as commercial soap, natural oils and Preferal® (based on the entomopathogenic fungus Isaria fumosorosea ...

  6. A Primary Screening and Applying of Plant Volatiles as Repellents to Control Whitefly Bemisia tabaci (Gennadius) on Tomato

    NASA Astrophysics Data System (ADS)

    Du, Wenxiao; Han, Xiaoqing; Wang, Yubo; Qin, Yuchuan

    2016-02-01

    With the goal of finding a new way to reduce population densities of Bemisia tabaci biotype Q in greenhouses, seven repellent volatile chemicals and their combinations were screened. The mixture of DLCO (D-limonene, citral and olive oil (63:7:30)) had a better cost performance(SC50 = 22.59 mg/ml)to repel whiteflies from settling than the other mixtures or single chemicals. In the greenhouse, in both the choice test and the no-choice tests, the number of adult whiteflies that settled on 1% DLCO-treated tomato plants was significantly lower than those settling on the control plants for the different exposure periods (P < 0.01). In the choice test, the egg amount on the treated tomato plants was significantly lower (P < 0.01) than that on the control plants, but there was no significant difference (P > 0.05) between the number of eggs on treated and control plants in the no-choice test. Compared with the controls, 1% DLCO did not cause significantly statistic mortality rates (P > 0.05) out of different living stages of B. tabaci. The tests for evaluating the repellent efficacy, showed that a slow-releasing bottle containing the mixture had a period of efficacy of 29 days, and the application of this mixture plus a yellow board used as a push-pull strategy in the greenhouse was also effective.

  7. A Primary Screening and Applying of Plant Volatiles as Repellents to Control Whitefly Bemisia tabaci (Gennadius) on Tomato

    PubMed Central

    Du, Wenxiao; Han, Xiaoqing; Wang, Yubo; Qin, Yuchuan

    2016-01-01

    With the goal of finding a new way to reduce population densities of Bemisia tabaci biotype Q in greenhouses, seven repellent volatile chemicals and their combinations were screened. The mixture of DLCO (D-limonene, citral and olive oil (63:7:30)) had a better cost performance(SC50 = 22.59 mg/ml)to repel whiteflies from settling than the other mixtures or single chemicals. In the greenhouse, in both the choice test and the no-choice tests, the number of adult whiteflies that settled on 1% DLCO-treated tomato plants was significantly lower than those settling on the control plants for the different exposure periods (P < 0.01). In the choice test, the egg amount on the treated tomato plants was significantly lower (P < 0.01) than that on the control plants, but there was no significant difference (P > 0.05) between the number of eggs on treated and control plants in the no-choice test. Compared with the controls, 1% DLCO did not cause significantly statistic mortality rates (P > 0.05) out of different living stages of B. tabaci. The tests for evaluating the repellent efficacy, showed that a slow-releasing bottle containing the mixture had a period of efficacy of 29 days, and the application of this mixture plus a yellow board used as a push-pull strategy in the greenhouse was also effective. PMID:26907368

  8. Effect of starvation on vein preference of whitefly (Bemisia tabaci) on chilli as host plant

    NASA Astrophysics Data System (ADS)

    Siti Sakinah, A.; Mohamad Roff M., N.; Idris, A. B.

    2014-09-01

    The whitefly, Bemisia tabaci (Gennadius), is a cosmopolitan pest of horticultural crops. It caused serious damaged to the plants by feeding on plant saps as direct damage and transmit virus as indirect damage. Vein preferences of both female and male whitefly (WF) on chilli plant were recorded using Dinolite, a portable microscope, under laboratory conditions. WF adults of both sexes were starved for 2 and 4 hours before used for observation while no starvation for control individual (treatment). Results showed that both female and male preferred to feed on secondary veins rather than lamina, midrib and vein. From the result of whitefly preferred target site, hopefully this information will help to improve control tactics in WF management.

  9. Demographic analysis of arrhenotokous parthenogenesis and bisexual reproduction of Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae).

    PubMed

    Ding, Tianbo; Chi, Hsin; Gökçe, Ayhan; Gao, Yulin; Zhang, Bin

    2018-02-20

    Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) is a serious pest that is capable of bisexual and arrhenotokous reproduction. In arrhenotokous reproduction, virgin females initially produce male offspring; later, when their sons are sexually mature, the mothers begin bisexual reproduction by carrying out oedipal mating with their sons. Because a virgin female produces many male offspring before oedipal mating occurs, multiple oedipal mating is common. In this study, we investigated the effect of multiple oedipal mating on the population growth of F. occidentalis by using the age-stage, two-sex life table theory. In the arrhenotokous cohorts, all unfertilized eggs developed into males. In the bisexual cohorts, the offspring sex ratio was significantly female biased with the mean number of female offspring and male offspring being 72.68 and 29.00, respectively. These were the same as the net reproductive rate of female offspring and male offspring. In arrhenotokous cohorts, the number of males available for oedipal mating significantly affected the production of female offspring. The number of female offspring increased as the number of sons available for oedipal mating increased. Correctly characterizing this unique type of reproduction will provide important information for predicting the timing of future outbreaks of F. occidentalis, as well as aiding in formulating successful management strategies against the species.

  10. Biotype Characterization, Developmental Profiling, Insecticide Response and Binding Property of Bemisia tabaci Chemosensory Proteins: Role of CSP in Insect Defense

    PubMed Central

    Liu, Guoxia; Ma, Hongmei; Xie, Hongyan; Xuan, Ning; Guo, Xia; Fan, Zhongxue; Rajashekar, Balaji; Arnaud, Philippe; Offmann, Bernard; Picimbon, Jean-François

    2016-01-01

    Chemosensory proteins (CSPs) are believed to play a key role in the chemosensory process in insects. Sequencing genomic DNA and RNA encoding CSP1, CSP2 and CSP3 in the sweet potato whitefly Bemisia tabaci showed strong variation between B and Q biotypes. Analyzing CSP-RNA levels showed not only biotype, but also age and developmental stage-specific expression. Interestingly, applying neonicotinoid thiamethoxam insecticide using twenty-five different dose/time treatments in B and Q young adults showed that Bemisia CSP1, CSP2 and CSP3 were also differentially regulated over insecticide exposure. In our study one of the adult-specific gene (CSP1) was shown to be significantly up-regulated by the insecticide in Q, the most highly resistant form of B. tabaci. Correlatively, competitive binding assays using tryptophan fluorescence spectroscopy and molecular docking demonstrated that CSP1 protein preferentially bound to linoleic acid, while CSP2 and CSP3 proteins rather associated to another completely different type of chemical, i.e. α-pentyl-cinnamaldehyde (jasminaldehyde). This might indicate that some CSPs in whiteflies are crucial to facilitate the transport of fatty acids thus regulating some metabolic pathways of the insect immune response, while some others are tuned to much more volatile chemicals known not only for their pleasant odor scent, but also for their potent toxic insecticide activity. PMID:27167733

  11. Bemisia tabaci females from the Mediterranean (Q) species detect and avoid laying eggs in the presence of pyriproxyfen, a juvenile hormone analogue.

    PubMed

    Moshitzky, Pnina; Morin, Shai

    2014-10-01

    Pyriproxyfen, a juvenile hormone analogue, disrupts embryogenesis, metamorphosis and adult formation in Bemisia tabaci, but does not directly affect adult females. The effect of pyriproxyfen on egg-laying preference and performance of B. tabaci females and the influence of resistance to pyriproxyfen on these reproductive behaviours were studied. Choice experiments utilising cotton plants treated and not treated with pyriproxyfen revealed a significant preference for egg laying on non-treated plants both by resistant and susceptible females. No-choice assays indicated a reduction of ∼60% in the number of eggs laid on pyriproxyfen-treated plants by both resistant and susceptible females. The reduction in oviposition on treated plants was not accompanied with reduced expression of the vitellogenin gene or a delay in oocyte maturation, but significant accumulation of mature oocytes in the ovaries was observed, and could be reversed by transferring the females to non-treated plants. Pyriproxyfen caused reduced oviposition and enhanced mature oocyte accumulation in pyriproxyfen-resistant and pyriproxyfen-susceptible females. These findings can be explained by two alternative mechanisms: pyriproxyfen-regulated physiological arrest of oviposition, involving hormonal regulation of myotrophic factors, or the hierarchy-threshold behavioural theory of host choice, in which pyriproxyfen-treated plants are defined as low-quality hosts. Aspects of application are discussed. © 2013 Society of Chemical Industry.

  12. Sequencing and comparison of the Rickettsia genomes from the whitefly Bemisia tabaci Middle East Asia Minor I.

    PubMed

    Zhu, Dan-Tong; Xia, Wen-Qiang; Rao, Qiong; Liu, Shu-Sheng; Ghanim, Murad; Wang, Xiao-Wei

    2016-08-01

    The whitefly, Bemisia tabaci, harbors the primary symbiont 'Candidatus Portiera aleyrodidarum' and a variety of secondary symbionts. Among these secondary symbionts, Rickettsia is the only one that can be detected both inside and outside the bacteriomes. Infection with Rickettsia has been reported to influence several aspects of the whitefly biology, such as fitness, sex ratio, virus transmission and resistance to pesticides. However, mechanisms underlying these differences remain unclear, largely due to the lack of genomic information of Rickettsia. In this study, we sequenced the genome of two Rickettsia strains isolated from the Middle East Asia Minor 1 (MEAM1) species of the B. tabaci complex in China and Israel. Both Rickettsia genomes were of high coding density and AT-rich, containing more than 1000 coding sequences, much larger than that of the coexisted primary symbiont, Portiera. Moreover, the two Rickettsia strains isolated from China and Israel shared most of the genes with 100% identity and only nine genes showed sequence differences. The phylogenetic analysis using orthologs shared in the genus, inferred the proximity of Rickettsia in MEAM1 and Rickettsia bellii. Functional analysis revealed that Rickettsia was unable to synthesize amino acids required for complementing the whitefly nutrition. Besides, a type IV secretion system and a number of virulence-related genes were detected in the Rickettsia genome. The presence of virulence-related genes might benefit the symbiotic life of the bacteria, and hint on potential effects of Rickettsia on whiteflies. The genome sequences of Rickettsia provided a basis for further understanding the function of Rickettsia in whiteflies. © 2016 Institute of Zoology, Chinese Academy of Sciences.

  13. Phytohormone ecology : Herbivory byThrips tabaci induces greater ethylene production in intact onions than mechanical damage alone.

    PubMed

    Kendall, D M; Bjostad, L B

    1990-03-01

    Herbivory byThrips tabaci affected production of the phytohormone ethylene from living onion foliage. Ethylene analysis was performed by gas chromatography on intact onion tissue. Thrips feeding damage and a crushed thrips extract stimulated significantly greater production of eihylene than could be explained by either one-time or semicontinuous mechanical damage alone, suggesting that ethylene-inducing cues may be transferred to the plant during feeding. This is the first demonstration of increased ethylene production from insect-infested intact plants. This study suggests that herbivores affect both the phytohormone physiology and secondary chemistry of living plants because ethylene has been shown to enhance production of defensive phytochemicals.

  14. Effectiveness of two insect growth regulators against Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) and Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) and their impact on population densities of arthropod predators in cotton in Pakistan.

    PubMed

    Gogi, Muhammad D; Sarfraz, Rana M; Dosdall, Lloyd M; Arif, Muhammad J; Keddie, Andrew B; Ashfaq, Muhammad

    2006-10-01

    Field efficacies of two insect growth regulators (IGRs) at two recommended application rates, buprofezin at 370 and 555 g AI ha(-1) and lufenuron at 37 and 49 g AI ha(-1), were determined against the sweet potato whitefly, Bemisia tabaci (Gennadius), and the cotton bollworm, Helicoverpa armigera (Hübner), in experimental plots of cotton at the Directorate of Cotton Research, Faisalabad, Pakistan. Adverse effects of the IGRs on populations of associated arthropod predators, namely geocorids, chrysopids, coccinellids, formicids and arachnids, were also assessed. Both IGRs significantly reduced populations of B. tabaci at each application rate 24, 48 and 72 h after treatment, and higher doses were more effective than lower doses. Buprofezin was not effective against H. armigera at any tested dose for any time of treatment in any spray. Lufenuron applied at 37 and 49 g AI ha(-1) effectively suppressed H. armigera populations, resulting in significant reductions in crop damage. At lower doses, both IGRs appeared safe to predator populations, which did not differ significantly in IGR-treated versus untreated control plots. Population densities of formicids and coccinellids were significantly lower at high concentrations of both IGRs in treatment plots, possibly as a result of reduced prey availability. The potential role of buprofezin and lufenuron for control of B. tabaci and H. armigera in a spray programme and the likelihood of direct toxic effects of IGRs on predatory fauna of cotton are discussed.

  15. Cassava whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) in East African farming landscapes: a review of the factors determining abundance.

    PubMed

    Macfadyen, S; Paull, C; Boykin, L M; De Barro, P; Maruthi, M N; Otim, M; Kalyebi, A; Vassão, D G; Sseruwagi, P; Tay, W T; Delatte, H; Seguni, Z; Colvin, J; Omongo, C A

    2018-02-13

    Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a pest species complex that causes widespread damage to cassava, a staple food crop for millions of households in East Africa. Species in the complex cause direct feeding damage to cassava and are the vectors of multiple plant viruses. Whilst significant work has gone into developing virus-resistant cassava cultivars, there has been little research effort aimed at understanding the ecology of these insect vectors. Here we assess critically the knowledge base relating to factors that may lead to high population densities of sub-Saharan African (SSA) B. tabaci species in cassava production landscapes of East Africa. We focus first on empirical studies that have examined biotic or abiotic factors that may lead to high populations. We then identify knowledge gaps that need to be filled to deliver sustainable management solutions. We found that whilst many hypotheses have been put forward to explain the increases in abundance witnessed since the early 1990s, there are little published data and these tend to have been collected in a piecemeal manner. The most critical knowledge gaps identified were: (i) understanding how cassava cultivars and alternative host plants impact population dynamics and natural enemies; (ii) the impact of natural enemies in terms of reducing the frequency of outbreaks and (iii) the use and management of insecticides to delay the development of resistance. In addition, there are several fundamental methodologies that need to be developed and deployed in East Africa to address some of the more challenging knowledge gaps.

  16. Host Plant Effects on Alkaline Phosphatase Activity in the Whiteflies, Bemisia tabaci Biotype B and Trialeurodes vaporariorum

    PubMed Central

    Yan, Ying; Peng, Lu; Liu, Wan-Xue; Wan, Fang-Hao; Harris, Marvin K.

    2011-01-01

    Bemisia tabaci (Gennadius) B-biotype and Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae) often coexist on greenhouse-grown vegetable crops in northern China. The recent spread of B. tabaci B-biotype has largely replaced T. vaporariorum, and B-biotype now overlaps with T. vaporariorum where common hosts occur in most invaded areas. The impact of the B-biotype on the agro eco system appears to be widespread, and involves the ability to compete with and perhaps replace other phytophages like T. vaporariorum. An emerging hypothesis is that the B-biotype is physiologically superior due at least in part to an improved ability to metabolically utilize the alkaline phosphatase pathway. To test this hypothesis, alkaline phosphatase activity was studied in the B-biotype and T. vaporariorum after feeding on a number of different hosts for a range of durations, with and without host switching. Alkaline phosphatase activity in T. vaporariorum was 1.45 to 2.53-fold higher than that of the B-biotype when fed on tomato for 4 and 24 h, or switched from tomato to cotton and cabbage for the same durations. However, alkaline phosphatase activity in the B-biotype was 1.40 to 3.35-fold higher than that of T. vaporariorum when the host switching time was ∼72 and ∼120 h on the same plant. Both short-term (4 h) and long-term (72 h) switching of plant hosts can significantly affect the alkaline phosphatase activity in the two species. After ∼120 h, feeding on tomato and cotton alkaline phosphatase activity in the B-biotype was significantly higher than that of T. vaporariorum. It was shown that alkaline phosphatase aids the species feeding on different plant species, and that the B-biotype is physiologically superior to T. vaporariorum in utilizing the enzyme compared to T. vaporariorum over longer periods of feeding. PMID:21521136

  17. Plant quality and conspecific density effects on Anaphothrips obscurus (Thysanoptera: Thripidae) wing diphenism and population ecology.

    PubMed

    Reisig, Dominic D; Godfrey, Larry D; Marcum, Daniel B

    2010-04-01

    Factors that influence thysanopteran wing diphenism are not well known. In these studies, the impact of food quality, mediated through nitrogen addition, and conspecific density was explored on the wing diphenism of an herbivorous thrips species (Anaphothrips obscurus Müller) (Thysanoptera: Thripidae). In the first study, nitrogen was added to timothy grass (Phleum pretense L.) (Poales: Poaceae) transplants, and naturally occurring thrips populations were caged on the plants. Thrips abundance and foliar nutrients were assessed every 2 wk. A separate factorial experiment in growth chambers explored the impact of both plant nitrogen addition and thrips abundance on wing diphenism. Thrips density was manipulated by adding either 3 or 40 thrips to potted and caged timothy. Thrips abundance and foliar nutrients were measured 58 d after treatment placement. Plant quality directly affected thrips wing diphenism independent of thrips density in both experiments. Near the end of the field cage experiment, density may have indirectly impacted wing diphenism. In both experiments, plant quality and thrips density interacted to affect thrips population abundance. Plant quality alone can affect thrips wing diphenism, but it remains unclear whether density alone can affect thrips wing diphenism. This is a unique and understudied system that will be useful to examine generalized theories on the negative interaction between reproduction and dispersal.

  18. Sampling Plans for the Thrips Frankliniella schultzei (Thysanoptera: Thripidae) in Three Lettuce Varieties.

    PubMed

    Silva, Alisson R; Rodrigues-Silva, Nilson; Pereira, Poliana S; Sarmento, Renato A; Costa, Thiago L; Galdino, Tarcísio V S; Picanço, Marcelo C

    2017-12-05

    The common blossom thrips, Frankliniella schultzei Trybom (Thysanoptera: Thripidae), is an important lettuce pest worldwide. Conventional sampling plans are the first step in implementing decision-making systems into integrated pest management programs. However, this tool is not available for F. schultzei infesting lettuce crops. Thus, the objective of this work was to develop a conventional sampling plan for F. schultzei in lettuce crops. Two sampling techniques (direct counting and leaf beating on a white plastic tray) were compared in crisphead, looseleaf, and Boston lettuce varieties before and during head formation. The frequency distributions of F. schultzei densities in lettuce crops were assessed, and the number of samples required to compose the sampling plan was determined. Leaf beating on a white plastic tray was the best sampling technique. F. schultzei densities obtained with this technique were fitted to the negative binomial distribution with a common aggregation parameter (common K = 0.3143). The developed sampling plan is composed of 91 samples per field and presents low errors in its estimates (up to 20%), fast execution time (up to 47 min), and low cost (up to US $1.67 per sampling area). This sampling plan can be used as a tool for integrated pest management in lettuce crops, assisting with reliable decision making in different lettuce varieties before and during head formation. © The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  19. Accuracy, precision, and economic efficiency for three methods of thrips (Thysanoptera: Thripidae) population density assessment.

    PubMed

    Sutherland, Andrew M; Parrella, Michael P

    2011-08-01

    Western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), is a major horticultural pest and an important vector of plant viruses in many parts of the world. Methods for assessing thrips population density for pest management decision support are often inaccurate or imprecise due to thrips' positive thigmotaxis, small size, and naturally aggregated populations. Two established methods, flower tapping and an alcohol wash, were compared with a novel method, plant desiccation coupled with passive trapping, using accuracy, precision and economic efficiency as comparative variables. Observed accuracy was statistically similar and low (37.8-53.6%) for all three methods. Flower tapping was the least expensive method, in terms of person-hours, whereas the alcohol wash method was the most expensive. Precision, expressed by relative variation, depended on location within the greenhouse, location on greenhouse benches, and the sampling week, but it was generally highest for the flower tapping and desiccation methods. Economic efficiency, expressed by relative net precision, was highest for the flower tapping method and lowest for the alcohol wash method. Advantages and disadvantages are discussed for all three methods used. If relative density assessment methods such as these can all be assumed to accurately estimate a constant proportion of absolute density, then high precision becomes the methodological goal in terms of measuring insect population density, decision making for pest management, and pesticide efficacy assessments.

  20. Variation in preference and performance of Frankliniella occidentalis (Thysanoptera: Thripidae) on three strawberry cultivars.

    PubMed

    Rahman, Touhidur; Spafford, Helen; Broughton, Sonya

    2010-10-01

    Western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), is a major pest of strawberry, causing substantial yield loss through direct feeding on the flowers and fruit. Insecticides are the main method used for its control; however, F. occidentalis has developed resistance to insecticides from all major chemical classes. Chemical control is not a long-term strategy and integrated pest management is required. This study determined whether F. occidentalis damage could be reduced by host plant resistance or tolerance in three commercial strawberry cultivars (Fragaria X ananassa [Rosaceae]: 'Albion', 'Camarosa', and 'Camino Real'). Determination of resistance or tolerance to F. occidentalis was based on olfactory response, feeding damage, ovipositional preference, and host suitability for reproduction on leaves. F. occidentalis adults preferred to feed on Camarosa; however, if leaves had been fed on previously by conspecifics, there was no difference in feeding preference. Camarosa was the most preferred cultivar for oviposition, and more eggs were laid by F. occidentalis on Camarosa than either Albion or Camino Real. More larvae hatched and adults were reared from Camarosa than either Albion or Camino Real. The percentage of unhatched eggs, larvae, and pupae that died was highest on Camino Real. Survival rate was highest on Camarosa. Egg incubation, prepupation, pupation, and total developmental periods were shortest on Camarosa, but the larval period was longest on Camarosa. Camarosa was the most favorable cultivar for F. occidentalis population growth on leaves.

  1. Impact of production system on development of insecticide resistance in Frankliniella occidentalis (Thysanoptera: Thripidae).

    PubMed

    Bielza, P; Quinto, V; Grávalos, C; Fernández, E; Abellán, J

    2008-10-01

    The western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), has become one of the most difficult insects to control in the intensive agriculture of southeastern Spain. However, resistance problems are quite different in two neighboring areas, Murcia and Almeria, with distinct production systems. Thirty-six field populations of western flower thrips from sweet pepper crops were collected in two different dates in Murcia and Almeria in 2005 and 2006. Western flower thrips populations collected were exposed to a diagnostic concentration of spinosad, methiocarb, acrinathrin, and formetanate. The results allowed the recognition of higher levels of resistance in Almeria compared with Murcia throughout the growing season. The mortality at the diagnostic concentration for spinosad (120 ppm) in western flower thrips populations ranged from 34 to 81% in Almeria, and from 73 to 100% in Murcia. The mortalities at the diagnostic concentration to acrinathrin (800 ppm) and formetanate (8000 ppm) were 17-31% in Almeria and 77-100% in Murcia, and 14-41% in Almeria and 48-99% in Murcia, respectively, indicating large geographic variations. Toxicity of methiocarb was higher for western flower thrips populations from both areas. However, mortality at the diagnostic concentration of methiocarb (2000 ppm) varied from 56 to 90% in Almeria, and it was from 94 to 100% in Murcia. The impact of production systems and agricultural practices of each area on the development and stability of insecticide resistance is discussed.

  2. Tomato Pathogenesis-related Protein Genes are Expressed in Response to Trialeurodes vaporariorum and Bemisia tabaci Biotype B Feeding

    PubMed Central

    Puthoff, David P.; Holzer, Frances M.; Perring, Thomas M.

    2010-01-01

    The temporal and spatial expression of tomato wound- and defense-response genes to Bemisia tabaci biotype B (the silverleaf whitefly) and Trialeurodes vaporariorum (the greenhouse whitefly) feeding were characterized. Both species of whiteflies evoked similar changes in tomato gene expression. The levels of RNAs for the methyl jasmonic acid (MeJA)- or ethylene-regulated genes that encode the basic β-1,3-glucanase (GluB), basic chitinase (Chi9), and Pathogenesis-related protein-1 (PR-1) were monitored. GluB and Chi9 RNAs were abundant in infested leaves from the time nymphs initiated feeding (day 5). In addition, GluB RNAs accumulated in apical non-infested leaves. PR-1 RNAs also accumulated after whitefly feeding. In contrast, the ethylene- and salicylic acid (SA)-regulated Chi3 and PR-4 genes had RNAs that accumulated at low levels and GluAC RNAs that were undetectable in whitefly-infested tomato leaves. The changes in Phenylalanine ammonia lyase5 (PAL5) were variable; in some, but not all infestations, PAL5 RNAs increased in response to whitefly feeding. PAL5 RNA levels increased in response to MeJA, ethylene, and abscisic acid, and declined in response to SA. Transcripts from the wound-response genes, leucine aminopeptidase (LapA1) and proteinase inhibitor 2 (pin2), were not detected following whitefly feeding. Furthermore, whitefly infestation of transgenic LapA1:GUS tomato plants showed that whitefly feeding did not activate the LapA1 promoter, although crushing of the leaf lamina increased GUS activity up to 40 fold. These studies indicate that tomato plants perceive B. tabaci and T. vaporariorum in a manner similar to baterical pathogens and distinct from tissue-damaging insects. PMID:20927641

  3. DNA Barcode Analysis of Thrips (Thysanoptera) Diversity in Pakistan Reveals Cryptic Species Complexes.

    PubMed

    Iftikhar, Romana; Ashfaq, Muhammad; Rasool, Akhtar; Hebert, Paul D N

    2016-01-01

    Although thrips are globally important crop pests and vectors of viral disease, species identifications are difficult because of their small size and inconspicuous morphological differences. Sequence variation in the mitochondrial COI-5' (DNA barcode) region has proven effective for the identification of species in many groups of insect pests. We analyzed barcode sequence variation among 471 thrips from various plant hosts in north-central Pakistan. The Barcode Index Number (BIN) system assigned these sequences to 55 BINs, while the Automatic Barcode Gap Discovery detected 56 partitions, a count that coincided with the number of monophyletic lineages recognized by Neighbor-Joining analysis and Bayesian inference. Congeneric species showed an average of 19% sequence divergence (range = 5.6% - 27%) at COI, while intraspecific distances averaged 0.6% (range = 0.0% - 7.6%). BIN analysis suggested that all intraspecific divergence >3.0% actually involved a species complex. In fact, sequences for three major pest species (Haplothrips reuteri, Thrips palmi, Thrips tabaci), and one predatory thrips (Aeolothrips intermedius) showed deep intraspecific divergences, providing evidence that each is a cryptic species complex. The study compiles the first barcode reference library for the thrips of Pakistan, and examines global haplotype diversity in four important pest thrips.

  4. Thysanoptera infestation on skin and periorbital cellulitis in ostriches (Struthio camelus) aged 14 months.

    PubMed

    Cooper, R G

    2007-06-01

    To report the infestation of Thysanoptera (Limothrips denticornis) on ostriches (Struthio camelus) and to determine their relative density. A farm in Poland was studied on which ostriches aged 14 months were severely infested with L. denticornis (thrips). Thrips were collected and their density on the neck, torso and legs (10 cm2) of 85 ostriches determined at 0600, 1200 and 1800 h, respectively, over 7 days. At the same times, apparent densities of thrips/m2 were determined in adjacent grassy areas (120 m2) on a muslin cloth impregnated with permethrin. Thrips were mounted onto slides in Hoyer's medium, for identification. The apparent density of thrips was greatest at 1200 h, and was greater on the neck than the torso and legs (p=0.03). In adjacent surroundings, densities were also highest at 1200 h (mean 199 (SE 9.3) thrips/m2) and were similar to the maximum densities recorded on the necks of ostriches at that time (mean 205 (SE 6.4) thrips/m2). Ostriches engaged in excessive preening and attempted to scratch their head/neck with their feet. Numerous small, pale red papules were observed on the skin. Observations of periorbital cellulitis, conjunctivitis, blepharitis, watery discharge, inflammation, and sclerotic discolouration were noted in 65 ostriches. Observations were commensurate with L. denticornis infestation. Infestation may exacerbate stress levels and subsequently lead to a reduction in feed intake and performance. The infestation and subsequent irritation from thrips impacts negatively on the general health of ostriches by damaging skin and irritating eyes.

  5. The Genome of Cardinium cBtQ1 Provides Insights into Genome Reduction, Symbiont Motility, and Its Settlement in Bemisia tabaci

    PubMed Central

    Santos-Garcia, Diego; Rollat-Farnier, Pierre-Antoine; Beitia, Francisco; Zchori-Fein, Einat; Vavre, Fabrice; Mouton, Laurence; Moya, Andrés; Latorre, Amparo; Silva, Francisco J.

    2014-01-01

    Many insects harbor inherited bacterial endosymbionts. Although some of them are not strictly essential and are considered facultative, they can be a key to host survival under specific environmental conditions, such as parasitoid attacks, climate changes, or insecticide pressures. The whitefly Bemisia tabaci is at the top of the list of organisms inflicting agricultural damage and outbreaks, and changes in its distribution may be associated to global warming. In this work, we have sequenced and analyzed the genome of Cardinium cBtQ1, a facultative bacterial endosymbiont of B. tabaci and propose that it belongs to a new taxonomic family, which also includes Candidatus Amoebophilus asiaticus and Cardinium cEper1, endosymbionts of amoeba and wasps, respectively. Reconstruction of their last common ancestors’ gene contents revealed an initial massive gene loss from the free-living ancestor. This was followed in Cardinium by smaller losses, associated with settlement in arthropods. Some of these losses, affecting cofactor and amino acid biosynthetic encoding genes, took place in Cardinium cBtQ1 after its divergence from the Cardinium cEper1 lineage and were related to its settlement in the whitefly and its endosymbionts. Furthermore, the Cardinium cBtQ1 genome displays a large proportion of transposable elements, which have recently inactivated genes and produced chromosomal rearrangements. The genome also contains a chromosomal duplication and a multicopy plasmid, which harbors several genes putatively associated with gliding motility, as well as two other genes encoding proteins with potential insecticidal activity. As gene amplification is very rare in endosymbionts, an important function of these genes cannot be ruled out. PMID:24723729

  6. Bioactivity of indigenous medicinal plants against the cotton whitefly, Bemisia tabaci

    PubMed Central

    Hammad, E. Abou-Fakhr; Zeaiter, A.; Saliba, N.; Talhouk, S.

    2014-01-01

    Abstract Forty-one methanol extracts of 28 indigenous medicinal plant species were tested for their insecticidal bioactivity against cotton whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), adults and second nymphal instars under controlled conditions. This study is within a bioprospection context, in the form of utilizing local plant species as an alternative in sustainable agriculture development. Eighteen and nine plant extracts caused a significant decrease in number of live adult and nymphal whiteflies, respectively, compared to the control. This is the first report for the potential effect on survival of insects for 22 out of 28 tested medicinal plant species. Whole plant extracts of Ranunculus myosuroudes Boiss. and Kotschy (Ranunculaceae), Achillea damascena L. (Asteraceae), and Anthemis hebronica Boiss. and Kotschy (Asteraceae) and leaf extracts of Verbascum leptostychum DC. (Scrophulariaceae) and Heliotropium rotundifolium Boiss. (Borangiaceae) caused both repellent and toxic effects against the adult and second nymphal instars, respectively. Extracts of leaves and stems of Anthemis scariosa Boiss. (Asteraceae) and Calendula palestina Pers. (Asteraceae) were found to be more bioactive against the adult and nymphal instars, respectively, than extracts of other plant parts, such as flowers. Thus, the bioactive extracts of these medicinal plants have the potential to lower whitefly populations in a comprehensive pest management program in local communities, pending cultivation of these medicinal plant species. PMID:25204756

  7. Botanical insecticides in controlling Kelly's citrus thrips (Thysanoptera: Thripidae) on organic grapefruits.

    PubMed

    Vassiliou, V A

    2011-12-01

    Kelly's citrus thrips, Pezothrips kellyanus (Bagnall) (Thysanoptera: Thripidae) was first recorded in Cyprus in 1996 and became an economic citrus pest. In Cyprus, Kelly's citrus thrips larvae cause feeding damage mainly on immature lemon and grapefruit fruits. Use of botanical insecticides is considered an alternative tool compared with synthetic chemicals, in offering solutions for healthy and sustainable citrus production. During 2008-2010, the efficacy of the botanical insecticides azadirachtin (Neemex 0.3%W/W and Oikos 10 EC), garlic extract (Alsa), and pyrethrins (Vioryl 5%SC) was evaluated in field trials against Kelly's citrus thrips larval stage I and II aiming at controlling the pest's population and damage to organic grapefruit fruits. In each of the trial years treatments with pyrethrins and azadirachtin (Neemex 0.3%W/W) were the most effective against Kelly's citrus thrips compared with the untreated control (for 2008: P < 0.018; for 2009: P < 0.000; for 2010: P < 0.008). In 2008, the mean number of damaged fruits in treatments with pyrethrins and Neemex was 9.6 (19.2%) and 9.7 (19.5%) respectively, compared with 12.2 (24.3%) in the untreated control. In 2009, the mean number of damaged fruits in treatment with pyrethrins was 3.7 (7.3%) and 3.9 (7.8%) in treatment with Neemex compared with 8.6 (17.3%) in the untreated control, while in 2010 the mean damaged fruits in these treatments was recorded at 18.7 (37.5%) and 19.6 (39.2), respectively, compared with 29.6 fruits (59.2%) in the control. Oikos 10 EC showed significant effect only in 2009 and 2010. In these years, the mean number of damaged fruits was recorded at 5.5 and 21.2 compared with 8.6 and 29.6 fruits in the untreated control, respectively. Garlic extract showed the lowest effect from all the botanicals used compared with the untreated control.

  8. Aqueous Extracts of Some Medicinal Plants are as Toxic as Lmidacloprid to the Sweet Potato Whitefly, Bemisia tabaci

    PubMed Central

    Ateyyat, Mazen A.; Al-Mazra'awi, Mohammad; Abu-Rjai, Talal; Shatnawi, Mohamad A.

    2009-01-01

    Aqueous extracts of nine plants, known to have medicinal activity, were tested for their toxicity against the sweet potato whitefly, Bemisia tabaci Genn. (Homoptera: Aleurodidae) compared to the toxicity of the insecticide, Imidacloprid. Extracts of Lepidiuim sativum L. (Brassicales: Brassicaceae) killed 71 % of early stage nymphs, which was not significantly different from mortality caused by Imidacloprid. Treatment of pupae with three plant extracts, L. sativum, Achillea biebersteinii L. (Asterales: Asteraceae), or Retama raetam (Forssk.) Webb and Berthel (Fabales: Fabaceae) prevented adult development, and treatment with R. raetam extract killed adults, at levels that were not significantly different from Imidacloprid. None of the other plants showed significant toxicity. However extracts of four plants, Pimpinella anisum L. (Apiales: Apiaceae), Galium longifolium (Sibth. and SM.) (Gentianales: Rubiaceae), R. raetam and Ballota undulata Bentham (Lamiales: Lamiaceae) had a repellent effect. PMID:19613450

  9. Life cycle of Cosmolaelaps jaboticabalensis (Acari: Mesostigmata: Laelapidae) on Frankliniella occidentalis (Thysanoptera: Thripidae) and two factitious food sources.

    PubMed

    Moreira, Grazielle Furtado; de Morais, Matheus Rovere; Busoli, Antônio Carlos; de Moraes, Gilberto José

    2015-02-01

    The aim of this work was to study the life cycle of Cosmolaelaps jaboticabalensis Moreira, Klompen and Moraes preying on Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), a serious cosmopolitan pest of different crops, as well as on Protorhabditis sp. (Nematoda: Rhabditidae) and Tyrophagus putrescentiae (Astigmatina: Acaridae), prospective factitious foods for the mass rearing of the predator. Experiments were conducted in a chamber at 25 ± 1 °C, 70 ± 10 % RH and in the dark. Total immature development (egg-adult) was completed in 12.3 ± 5, 6.6 ± 0.6 and 7.1 ± 0.6 on F. occidentalis, Protorhabditis sp. and T. putrescentiae, respectively. Fecundity and intrinsic rate of increase were higher on Protorhabditis sp. (71.6 ± 9.1 eggs/female; 0.28 female/female/day) than on F. occidentalis (63.8 ± 14.8; 0.23) and T. putrescentiae (43.1 ± 8.9; 0.23). Cosmolaelaps jaboticabalensis reproduces by thelytokous parthenogenesis and its larval stages can be completed without feeding. Protonymphs and deutonymphs can survive in the absence of food for about a month, and adults for almost 2 months. It was concluded that C. jaboticabalensis is a promising biological control agent of F. occidentalis and that it may be mass reared with the use of Protorhabditis sp. or T. putrescentiae.

  10. Development of Species-Specific Primers for Agronomical Thrips and Multiplex Assay for Quarantine Identification of Western Flower Thrips.

    PubMed

    Yeh, W B; Tseng, M J; Chang, N T; Wu, S Y; Tsai, Y S

    2014-10-01

    While morphological identification of thrips species has been difficult because of their minute size and a lack of easily recognizable characteristics, molecular identification based on the development of specific molecular markers can be easily and reliably carried out. Among the known molecular markers, the nuclear internal transcribed spacer (ITS) exhibits distinguishable variations among thrips species. In this study, sequences of ITS2 region of 10 agriculturally important thrips were established to design species-specific primers for polymerase chain reaction (PCR). ITS2 sequence variations within these species were far less than those among species, indicating the suitability of this marker for species-specific primers design. These primers, though with one or two sporadically variable positions, showed a good efficacy within species. The specificity of these primers, examined on thrips species belonging to 15 genera, proved satisfactory. Furthermore, a multiplex PCR was used successfully for identifying Frankliniella occidentalis (Pergande), an insect pest monitored for quarantine purpose, and three additional thrips also commonly found in imported agricultural products and field samples, i.e., Thrips tabaci Lindeman, Thrips hawaiiensis (Morgan), and Frankliniella intonsa (Trybom). This study has demonstrated that specific primers and multiplex PCR based on ITS2 are reliable, convenient, and diagnostic tool to discriminate thrips species of quarantine and agricultural importance. © 2014 Entomological Society of America.

  11. Naturally occurring bioactive compounds from four repellent essential oils against Bemisia tabaci whiteflies.

    PubMed

    Deletre, Emilie; Chandre, Fabrice; Barkman, Barbara; Menut, Chantal; Martin, Thibaud

    2016-01-01

    In tropical countries, netting is an effective sustainable tool for protecting horticultural crops against Lepidoptera, although not against small pests such as Bemisia tabaci, while smaller mesh netting can be used in temperate regions. A solution is to combine a net with a repellent. Previously we identified repellent essential oils: lemongrass (Cymbopogon citratus), cinnamon (Cinnamomum zeylanicum), cumin (Cuminum cyminum) and citronella (Cymbopogon winternarius). The present study was designed to identify the active compounds of these essential oils, characterise their biological activity and examine their potential for coating nets. We investigated the efficiency and toxicity of nets dipped in different solutions. We then studied the repellent effect with an olfactometer and the irritant effect by videotracking. Geraniol and citronellol were the most promising net coatings owing to their repellent effect. The repellency, irritancy or toxicity varied with the product and concentration, and these features were independent, indicating that the repellent and the irritant/toxic mechanisms were not the same. The combined effects of these different compounds account for the bioactivity of the mixture, suggesting interactions between the compounds. This new sustainable strategy for protecting vegetable crops against whiteflies is discussed, in addition to the use of companion plants that could produce such bioactive compounds. © 2015 Society of Chemical Industry.

  12. RNAi-mediated resistance to whitefly (Bemisia tabaci) in genetically engineered lettuce (Lactuca sativa).

    PubMed

    Ibrahim, Abdulrazak B; Monteiro, Tatiane R; Cabral, Glaucia B; Aragão, Francisco J L

    2017-10-01

    RNA interference (RNAi)-based transgenic technologies have evolved as potent biochemical tools for silencing specific genes of plant pathogens and pests. The approach has been demonstrated to be useful in silencing genes in insect species. Here, we report on the successful construction of RNAi-based plasmid containing an interfering cassette designed to generate dsRNAs that target a novel v-ATPase transcript in whitefly (Bemisia tabaci), an important agricultural pest in tropical and sub-tropical regions. The presence of the transgene was confirmed in T 0 and T 1 generations of transgenic lettuce lines, segregating in a Mendelian fashion. Seven lines were infested with whiteflies and monitored over a period of 32 days. Analysis of mortality showed that within five days of feeding, insects on transgenic plants showed a mortality rate of 83.8-98.1%. In addition, a reduced number of eggs (95 fold less) was observed in flies feeding on transgenic lettuce plants than insects on control lines. Quantitative reverse transcription PCR showed decreased expression level of endogenous v-ATPase gene in whiteflies feeding on transgenic plants. This technology is a foundation for the production of whitefly-resistant commercial crops, improving agricultural sustainability and food security, reducing the use of more environmentally aggressive methods of pest control.

  13. Effect of Zohar LQ-215, a biorational surfactant, on the sweetpotato whitefly Bemisia tabaci (biotype b).

    PubMed

    Ishaaya, I; Khasdan, V; Horowitz, A Rami

    2006-01-01

    Zohar LQ-215, a surfactant based on plant oils, able to control nymphs of the whitefly, Bemisia tabaci (Gennadius), under laboratory and field conditions. To evaluate the effects of the surfactant on the nymph stages of whitefly under laboratory conditions, potted cotton seedlings infested with 1st- or 3rd-instars were treated with the compound aqueous solutions. LC90 values of Zohar LQ-215 on 1st and 3rd-nymphs, based on mortality curves, were 0.78% and 1.14%, respectively. Adult mortality of 12% and 19% was obtained at concentrations of 0.5% and 1%, respectively. Under both laboratory and, in some cases, under field conditions, greater mortality was achieved when combining Zohar LQ-215 with the insect growth regulator buprofezin than when either insecticide was applied separately. Our results indicate that Zohar LQ-215 could serve as a potential compound for controlling whiteflies under light to moderate infestation and could be used in combination with other rational insecticides such as buprofezin for controlling whiteflies in integrated pest management programs.

  14. Repellency of essential oils to Frankliniella occidentalis (Thysanoptera: Thripidae) as affected by type of oil and polymer release.

    PubMed

    Picard, Isabelle; Hollingsworth, Robert G; Salmieri, Stéphane; Lacroix, Monique

    2012-08-01

    Eight essential oils [0.125-1.0% (vol:vol) in acetone] were separately deposited on leaf disks to evaluate their potential to repel western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), adult females. Two of the best-performing essential oils were incorporated into polymer matrices of methyl cellulose or alginate [0.5 or 1% (wt:vol)] to verify the potential of the polymer to extend repellency of oils over time (24-120 h). Results showed that at a concentration of 0.5%, Thymus vulgaris L. (common thyme) and Satureja montana L. (winter savory) were the most repellent essential oils. For these two treatments, no western flower thrips were counted on treated leaf disks 60 min after the start of the test. T. serpyllum and O. compactum also showed repellency values > or = 90% at this concentration. With both the alginate and methyl cellulose polymers, the incorporation of polymers into treatment solutions containing 0.5% concentrations of S. montana and T. serpyllum resulted in higher repellency compared with treatment solutions lacking these polymers for a minimum of 3 d. For the alginate polymer, differences associated with polymer concentrations were most dramatic. High repellency was maintained for 4 d when a 0.5% concentration of the alginate was used in combination with a 0.5% concentration of S. montana. The use of repellent oils with polymers that extend their repellency may prove useful for both pre- and postharvest applications in flower crops.

  15. Sublethal Effects of Beauveria bassiana (Ascomycota: Hypocreales) on Life Table Parameters of Frankliniella occidentalis (Thysanoptera: Thripidae).

    PubMed

    Zhang, Tao; Reitz, Stuart R; Wang, Haihong; Lei, Zhongren

    2015-06-01

    We assessed effects of parental exposure to Beauveria bassiana on life history traits of subsequent generations of western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). Progeny from individuals that survived fungal exposure as second instars had significantly shorter egg stages, but longer prepupal development times than corresponding untreated controls. However, survivorship to adulthood of these progeny groups did not differ. Although fecundities of the parental types did not differ, the sex ratio of progeny from fungal-treated parents was male-biased, whereas sex ratio of progeny from untreated control parents was even. We calculated life table parameters for the progeny and found that all parameters, except for generation time, were significantly less for the progeny of fungal-treated parents than for progeny of untreated parents. The intrinsic rate of increase, finite rate of increase, net reproductive rate, mean generation time, and gross reproductive rate were 0.199 d(-1), 1.229 d(-1), 21.84, 15.48 d, and 27.273, respectively, for progeny of treated thrips, and 0.266 d(-1), 1.316 d(-1), 52.540, 14.92 d, and 70.64, respectively, for progeny of control thrips. Consequently, population projections demonstrated that offspring of parents exposed to B. bassiana would increase their population more slowly than those from untreated parents. These results demonstrate that B. bassiana has sublethal effects that reduce the reproductive success of F. occidentalis and these effects should be taken into account when evaluating its use in management programs for F. occidentalis. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. Comparison of Frankliniella fusca and Frankliniella occidentalis (Thysanoptera: Thripidae) as Vectors for a Peanut Strain of Tomato Spotted Wilt Orthotospovirus.

    PubMed

    Arthurs, Steven P; Heinz, Kevin M; Mitchell, Forrest L

    2018-06-06

    Tomato spotted wilt orthotospovirus (TSWV) is a major disease in peanut, Arachis hypogaea L., across peanut producing regions of the United States and elsewhere. Two thrips, Frankliniella fusca Hinds and Frankliniella occidentalis Pergande (Thysanoptera: Thripidae), are considered important vectors of TSWV in peanut in the Southeast. We compared the efficiency of acquisition (by larvae) and transmission (adults) of both thrips species for TSWV (Texas peanut-strain) to leaf disks of peanut (Florunner), as well as to Impatiens walleriana Hook. f. (Dwarf White Baby) and Petunia hybrida Juss. 'Fire Chief' using double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA). Both species were competent TSWV vectors in peanut and Impatiens, although F. fusca was the more efficient vector overall, i.e., virus acquisition and transmission rates for F. fusca averaged over several bioassays were 51.7 and 26.6%, respectively, compared with 20.0 and 15.3% for F. occidentalis. Neither species effectively transmitted this TSWV strain to Petunia (i.e., ≤3.6% transmission). We found statistically similar virus acquisition and transmission rates between both sexes for each species. We also detected no differences in TSWV-acquisition and transmission frequency between macropterous and brachypterous (short-wing) forms of F. fusca collected from a field population in south Texas. DAS-ELISA failed to detect low levels of TSWV in a few thrips that subsequently proved to be competent vectors.

  17. Effectiveness of insecticide-treated and non-treated trap plants for the management of Frankliniella occidentalis (Thysanoptera: Thripidae) in greenhouse ornamentals.

    PubMed

    Buitenhuis, Rosemarije; Shipp, J Les; Jandricic, Sarah; Murphy, Graeme; Short, Mike

    2007-09-01

    The effectiveness of trap cropping as an integrated control strategy against western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), was explored in potted chrysanthemum, Dendranthema grandiflora (Tzvelev), greenhouse crops. The efficacy of flowering chrysanthemum trap plants, either treated with the insecticide spinosad or untreated, to regulate F. occidentalis populations was tested at different spatial scales (small cage, large cage and commercial greenhouse) and for different time periods (1 or 4 weeks). It was demonstrated that flowering chrysanthemums as trap plants lower the number of adult F. occidentalis in a vegetative chrysanthemum crop and, as a result, reduce crop damage. In the 4 week large-cage trial and the commercial trial, significant differences between the control and the trap plant treatments started to appear in the third week of the experiment. Larvae were only significantly reduced by the presence of trap plants in the 1 week small-cage trials. There were no significant differences between treatments with spinosad-treated and untreated trap plants in the number of F. occidentalis on the crop. This suggests that there was minimal movement of adult F. occidentalis back and forth between the trap plants and the crop to feed and oviposit. It is concluded that the trap plant strategy is a useful tool for integrated pest management against F. occidentalis in greenhouses. 2007 Crown in the right of Canada

  18. Bemisia tabaci Q carrying tomato yellow leaf curl virus strongly suppresses host plant defenses

    PubMed Central

    Shi, Xiaobin; Pan, Huipeng; Zhang, Hongyi; Jiao, Xiaoguo; Xie, Wen; Wu, Qingjun; Wang, Shaoli; Fang, Yong; Chen, Gong; Zhou, Xuguo; Zhang, Youjun

    2014-01-01

    The concurrence of tomato yellow leaf curl virus (TYLCV) with the spread of its vector Bemisia tabaci Q rather than B in China suggests a more mutualistic relationship between TYLCV and Q. Here, we investigated the hypothesis that viruliferous B and Q have different effects on plant defenses. We found the fecundity of nonviruliferous B, nonviruliferous Q, viruliferous Q and viruliferous B was 11.080, 12.060, 10.760, and 11.220 respectively on plants previously attacked by the other biotype, however, on their respective noninfested control leaves fecundity was 12.000, 10.880, 9.760, and 8.020 respectively. Only viruliferous B had higher fecundity on viruliferous Q-infested plants than on control plants. The longevity of viruliferous B showed the same phenomenon. At 1 d infestion, the jasmonic acid content in leaves noninfested and in leaves infested with nonviruliferous B, nonviruliferous Q, viruliferous B and viruliferous Q was 407.000, 281.333, 301.333, 266.667 and 134.000 ng/g FW, respectively. The JA content was lowest in viruliferous Q-infested leaves. The proteinase inhibitor activity and expression of JA-related upstream gene LOX and downstream gene PI II showed the same trend. The substantial suppression of host defenses by Q carrying TYLCV probably enhances the spread of Q and TYLCV in China. PMID:24912756

  19. The risk of exotic and native plants as hosts for four pest thrips (Thysanoptera: Thripinae).

    PubMed

    Schellhorn, N A; Glatz, R V; Wood, G M

    2010-10-01

    Interactions among insect pests, crops and weeds are well recognised. In fact, the elimination of weed hosts outside of the crop is a common practice to control many insect-vectored viruses. However, little is known about interactions among insect pests, crops and native vegetation, and whether native plants may be used to revegetate areas where weed hosts have been eliminated as part of horticultural management regimes. We used the Northern Adelaide Plains horticultural region (South Australia, Australia) as a model system to study the potential of various plant taxa in hosting four pest thrips (three exotic, one native; Frankliniella occidentalis, F. schultzei, Thrips tabaci and T. imaginis) when located adjacent to, and distant from, horticultural crops. Flower funnels were used for standardised sampling of thrips on flowers from 19 exotic weed and 12 native plant species, representing 13 and three families, respectively. Flowers were sampled monthly over a year, and statistical analyses were performed to identify significant determinants of probability of thrips occurrence and density. Plant family was found to significantly influence both measures for each thrips species. In addition, crop proximity influenced the probability of occurrence for the two Frankliniella species (but only influenced density of the key pest F. occidentalis), and season influenced density of all four pest thrips. All native plant species tested had a low likelihood of hosting the three exotic thrips species. Overall, results suggest that judicious choice of surrounding vegetation has potential to be an important component of integrated pest management (IPM) while increasing biodiversity conservation.

  20. Expression Profiling in Bemisia tabaci under Insecticide Treatment: Indicating the Necessity for Custom Reference Gene Selection

    PubMed Central

    Zhou, Xuguo; Gao, Xiwu

    2014-01-01

    Finding a suitable reference gene is the key for qRT-PCR analysis. However, none of the reference gene discovered thus far can be utilized universally under various biotic and abiotic experimental conditions. In this study, we further examine the stability of candidate reference genes under a single abiotic factor, insecticide treatment. After being exposed to eight commercially available insecticides, which belong to five different classes, the expression profiles of eight housekeeping genes in the sweetpotato whitefly, Bemisia tabaci, one of the most invasive and destructive pests in the world, were investigated using qRT-PCR analysis. In summary, elongation factor 1α (EF1α), α-tubulin (TUB1α) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were identified as the most stable reference genes under the insecticide treatment. The initial assessment of candidate reference genes was further validated with the expression of two target genes, a P450 (Cyp6cm1) and a glutathione S-transferase (GST). However, ranking of reference genes varied substantially among intra- and inter-classes of insecticides. These combined data strongly suggested the necessity of conducting custom reference gene selection designed for each and every experimental condition, even when examining the same abiotic or biotic factor. PMID:24498122

  1. Whitefly Bemisia tabaci (Homoptera: Aleyrodidae) infestation on cassava genotypes grown at different ecozones in Nigeria.

    PubMed

    Ariyo, O A; Dixon, A G O; Atiri, G I

    2005-04-01

    Large-scale screening of cassava, Manihot esculenta Crantz, genotypes for resistance to infestation by whitefly Bemisia tabaci Gennadius, the vector of cassava mosaic geminiviruses, is limited. A range of new cassava elite clones were therefore assessed for the whitefly infestation in the 1999/2000 and 2000/2001 cropping seasons in experimental fields of International Institute of Tropical Agriculture, Ibadan, Nigeria. On each scoring day, between 0600 and 0800 hours when the whiteflies were relatively immobile, adult whitefly populations on the five topmost expanded leaves of cassava cultivars were counted. All through the 6-mo scoring period, there was a highly significant difference in whitefly infestation among the new cassava elite clones. Vector population buildup was observed in Ibadan (forest-savanna transition zone) and Onne (humid forest), 2 mo after planting (MAP). Mean infestation across cassava genotypes was significantly highest (16.6 whiteflies per plant) in Ibadan and lowest in Zaria (0.2). Generally, whitefly infestation was very low in all locations at 5 and 6 MAP. During this period, cassava genotypes 96/1439 and 91/02324 significantly supported higher infestations than other genotypes. Plants of 96/1089A and TMS 30572 supported the lowest whitefly infestation across cassava genotypes in all locations. The preferential whitefly visitation, the differences between locations in relation to whitefly population, cassava mosaic disease, and the fresh root yield of cassava genotypes are discussed.

  2. Tissue-specific changes of glutamine synthetase activity in oats after rhizosphere infestation by Pseudomonas syringae pv. tabaci. Final report

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Knight, T.J.; Temple, S.; Sengupta-Gopalan, C.

    1996-05-15

    Oats (Avena sativa L. lodi) tolerant of rhizosphere infestation by Pseudomonas syringae pv. tabaci when challenged by the pathogen experience tissue-specific alterations of ammonia assimilatory capabilities. Altered ammonia assimilatory potentials between root and leaf tissue result from selective inactivation of glutamine synthetase (GS) by the toxin Tabtoxinine-B-lactam (TBL). Root GS is sensitive and leaf GSs are resistant to TBL inactivation. With prolonged challenge by the pathogen root GS activity decreases but leaf GS specific activity increase. Higher leaf GS activity is due to decreased rates of degradation rather than increased GS synthesis. Higher leaf GS activity and elevated levels ofmore » GS polypeptide appear to result from a limited interaction between GS and TBL leading to the accumulation of a less active but more stable GS holoenzyme. Tolerant challenged oats besides surviving rhizosphere infestation, experience enhanced growth. A strong correlation exists between leaf GS activity and whole plant fresh weight, suggesting that tissue-specific changes in ammonia assimilatory capability provides the plant a more efficient mechanism for uptake and utilization of nitrogen.« less

  3. Intra- and Interspecific Competition Between Western Flower Thrips and Sweetpotato Whitefly

    PubMed Central

    Wu, Qing-Jun; Hou, Wen-Jie; Li, Fei; Xu, Bao-Yun; Xie, Wen; Wang, Shao-Li; Zhang, You-Jun

    2014-01-01

    Abstract The western flower thrips, Frankliniella occidentalis (Pergande), and the sweetpotato whitefly, Bemisia tabaci (Gennadius), are both invasive insect pests and are present in most of the same agricultural crops without a clear dominance of either species. Here, intra- and interspecific competition in B. tabaci and F. occidentalis was determined under controlled experiments. The results showed that intraspecific competition was distinct in F. occidentalis and that the co-occurrence of B. tabaci had a strong effect on F. occidentalis , resulting in a decrease in oviposition. Significant intraspecific competition was found in B. tabaci , and the coexistence of F. occidentalis had limited effect on the oviposition of B. tabaci . In a selective host plant preference experiment, both F. occidentalis and B. tabaci preferred eggplants most, followed by cucumbers and tomatoes. On cucumber plants, B. tabaci was predominant, whereas on eggplant and tomato plants, F. occidentalis and B. tabaci exhibited comparative competitive abilities during the initial stage. However, over time, higher numbers of B. tabaci than that of F. occidentalis were found on the two host plants. Our in vitro and potted plant experiments indicate that B. tabaci is competitively superior to F. occidentalis , which might help to explain their differential distribution patterns in China. PMID:25480973

  4. Dissipation rate of thiacloprid and its control effect against Bemisia tabaci in greenhouse tomato after soil application.

    PubMed

    Dong, Sa; Qiao, Kang; Wang, Hongyan; Zhu, Yukun; Xia, Xiaoming; Wang, Kaiyun

    2014-08-01

    Thiacloprid is a chloronicotinyl insecticide that is quite effective against sucking insects. In this study, when thiacloprid was applied at two different rates (normal rate 15 kg ha(-1) , double rate 30 kg ha(-1) ), the systemic distribution and residue of thiacloprid as well as its control effect against whitefly (Bemisia tabaci) were investigated in greenhouse tomato after soil application. The results showed that thiacloprid was present in the tomato leaves until day 25, and then its amount was less than 0.005 mg kg(-1) and could not be detected. Thiacloprid residue in the tomato stems basically remained at a stable low level throughout the experimental period. Thiacloprid in soil had half-lives of 11.8 and 12.5 days for the normal treatment and the double treatment respectively. The control efficiency of whiteflies was about 90% from day 1 to day 10. This was followed by a slow decline, but efficiency was still higher than 50% until day 21. In addition, no significant differences were noted in the control effect of thiacloprid on whiteflies between the two different rates. Soil application of thiacloprid at the normal rate can effectively control whiteflies, with high efficiency and long persistence. © 2013 Society of Chemical Industry.

  5. Dynamics of Bemisia tabaci biotypes and insecticide resistance in Fujian province in China during 2005–2014

    PubMed Central

    Yao, Feng-Luan; Zheng, Yu; Huang, Xiao-Yan; Ding, Xue-Ling; Zhao, Jian-Wei; Desneux, Nicolas; He, Yu-Xian; Weng, Qi-Yong

    2017-01-01

    The whitefly Bemisia tabaci (Gennadius) is an important agricultural insect pest worldwide. The B and Q biotypes are the two most predominant and devastating biotypes prevalent across China. However, there are few studies regarding the occurrence of the Q biotype in Fujian Province, China, where high insecticide resistance has been reported in the B biotype. Differences in some biological characteristics between the B and Q biotypes, especially insecticide resistance, are considered to affect the outcome of their competition. Extensive surveys in Fujian revealed that the B biotype was predominant during 2005–2014, whereas the Q biotype was first detected in some locations in 2013 and widely detected throughout the province in 2014. Resistance to neonicotinoids (that have been used for more than 10 years) exhibited fluctuations in open fields, but showed a continual increasing trend in protected areas. Resistance to lambda-cyhalothrin, chlorpyrifos, and abamectin exhibited a declining trend. Resistance to novel insecticides, such as nitenpyram, pymetrozine, sulfoxaflor, and cyantraniliprole, in 2014 was generally below a moderate level. A decline in insecticide resistance in the B biotype and the rapid buildup of protected crops under global temperature increase may have promoted the establishment of the Q biotype in Fujian. PMID:28112233

  6. Intra- and interspecific competition between western flower thrips and sweetpotato whitefly.

    PubMed

    Wu, Qing-Jun; Hou, Wen-Jie; Li, Fei; Xu, Bao-Yun; Xie, Wen; Wang, Shao-Li; Zhang, You-Jun

    2014-01-01

    The western flower thrips, Frankliniella occidentalis (Pergande), and the sweetpotato whitefly, Bemisia tabaci (Gennadius), are both invasive insect pests and are present in most of the same agricultural crops without a clear dominance of either species. Here, intra- and interspecific competition in B. tabaci and F. occidentalis was determined under controlled experiments. The results showed that intraspecific competition was distinct in F. occidentalis and that the co-occurrence of B. tabaci had a strong effect on F. occidentalis, resulting in a decrease in oviposition. Significant intraspecific competition was found in B. tabaci, and the coexistence of F. occidentalis had limited effect on the oviposition of B. tabaci. In a selective host plant preference experiment, both F. occidentalis and B. tabaci preferred eggplants most, followed by cucumbers and tomatoes. On cucumber plants, B. tabaci was predominant, whereas on eggplant and tomato plants, F. occidentalis and B. tabaci exhibited comparative competitive abilities during the initial stage. However, over time, higher numbers of B. tabaci than that of F. occidentalis were found on the two host plants. Our in vitro and potted plant experiments indicate that B. tabaci is competitively superior to F. occidentalis, which might help to explain their differential distribution patterns in China. © The Author 2014. Published by Oxford University Press on behalf of the Entomological Society of America.

  7. Nuclear and cytoplasmic differentiation among Mediterranean populations of Bemisia tabaci: testing the biological relevance of cytotypes.

    PubMed

    Terraz, Gabriel; Gueguen, Gwenaelle; Arnó, Judit; Fleury, Frédéric; Mouton, Laurence

    2014-10-01

    The taxonomy of the species complex Bemisia tabaci is still an unresolved issue. Recently, phylogenetic analysis based on mtCOI identified 31 cryptic species. However, mitochondrial diversity is observed within these species, associated with distinct symbiotic bacterial communities forming associations, which here are called cytotypes. The authors investigated the biological significance of two cytotypes (Q1 and Q2) belonging to the Mediterranean species, which have only been found in allopatry in the Western Mediterranean to date. Sampling was done over a few years in Western Europe, and sympatric situations were found that allowed their reproductive compatibility to be tested in the field with the use of microsatellites. The field survey indicated that, in spite of its recent introduction, Q2 is well established in France and Spain, where it coexists with Q1. Microsatellite data showed that, in allopatry, Q1 and Q2 are highly differentiated, while there is little or no genetic differentiation when they coexist in sympatry, suggesting a high rate of hybridisation. Crossing experiments in the lab confirmed their interfertility. Q1 and Q2 hybridise, which confirms that they belong to the same species, in spite of the high degree of genetic differentiation at both the cytoplasmic and nuclear levels, and also suggests that their symbiotic bacteria do not prevent hybridisation. © 2014 Society of Chemical Industry.

  8. Efficacy of entomopathogenic nematode Steinernema feltiae (Rhabditida: Steinernematidae) as influenced by Frankliniella occidentalis (Thysanoptera: Thripidae) developmental stage and host plant stage.

    PubMed

    Buitenhuis, R; Shipp, J L

    2005-10-01

    Entomopathogenic nematodes were investigated as an alternative biological control strategy for western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), in ornamental greenhouse crops, by using potted chrysanthemum as a model crop. The susceptibility of various life stages of F. occidentalis to different concentrations of the nematode Steinernema feltiae (Filipjev) (Rhabditida: Steinernematidae) was investigated in petri dish bioassays. This was followed with trials using potted chrysanthemums comparing the efficacy of nematode application to plants in vegetative (exposed habitat) versus flowering (cryptic habitat) stages. In both trials, the effect of the wetting agent Agral 90 (nonylphenoxy polyethoxyethanol), which is used in combination with the nematode spray, on F. occidentalis mortality was assessed. In petri dish trials, the prepupae and pupae were the most susceptible developmental stages of F. occidentalis to infection by S. feltiae. First and second instars were killed by very high rates of nematodes (> or =20,000 infective juveniles per milliliter), but corrected mortality was only approximately 28-37%. No significant mortality was observed for adult thrips. Results from the petri dish trials were confirmed on chrysanthemum plants. Foliar application of S. feltiae did not result in significant mortality in larvae or adults. No significant differences in efficacy were detected by application of nematodes on vegetative versus flowering chrysanthemum. Agral 90 had a significant impact on mortality on the first stage larvae and prepupae in the petri dish trials but not in the plant trials. Thrips control by S. feltiae in greenhouses may be partly or completely due to prepupal and pupal mortality.

  9. Comparison of transmission of Papaya leaf curl China virus among four cryptic species of the whitefly Bemisia tabaci complex

    PubMed Central

    Guo, Tao; Guo, Qi; Cui, Xi-Yun; Liu, Yin-Quan; Hu, Jian; Liu, Shu-Sheng

    2015-01-01

    Begomoviruses are transmitted by cryptic species of the whitefly Bemisia tabaci complex, often in a species-specific manner. Papaya leaf curl China virus (PaLCuCNV) has been recorded to infect several crops including papaya, tomato and tobacco in China. To help assess the risks of spread of this virus, we compared the acquisition, retention and transmission of PaLCuCNV among four species of whiteflies, Middle East-Asia Minor 1 (MEAM1), Mediterranean (MED), Asia 1 and Asia II 7. All four species of whiteflies are able to acquire, retain and transmit the virus, but with different levels of efficiency. Transmission tests using tomato as the host plant showed that MEAM1 transmitted PaLCuCNV with substantially higher efficiency than did MED, Asia 1 and Asia II 7. Furthermore, accumulation of PaLCuCNV in the whiteflies was positively associated with its efficiency of transmitting the virus. Altogether, these findings indicate that MEAM1 is the most efficient vector for PaLCuCNV in the four species of whiteflies, and suggest that risks of PaLCuCNV pandemics are high in regions where MEAM1 occurs. PMID:26486606

  10. Comparison of transmission of Papaya leaf curl China virus among four cryptic species of the whitefly Bemisia tabaci complex.

    PubMed

    Guo, Tao; Guo, Qi; Cui, Xi-Yun; Liu, Yin-Quan; Hu, Jian; Liu, Shu-Sheng

    2015-10-21

    Begomoviruses are transmitted by cryptic species of the whitefly Bemisia tabaci complex, often in a species-specific manner. Papaya leaf curl China virus (PaLCuCNV) has been recorded to infect several crops including papaya, tomato and tobacco in China. To help assess the risks of spread of this virus, we compared the acquisition, retention and transmission of PaLCuCNV among four species of whiteflies, Middle East-Asia Minor 1 (MEAM1), Mediterranean (MED), Asia 1 and Asia II 7. All four species of whiteflies are able to acquire, retain and transmit the virus, but with different levels of efficiency. Transmission tests using tomato as the host plant showed that MEAM1 transmitted PaLCuCNV with substantially higher efficiency than did MED, Asia 1 and Asia II 7. Furthermore, accumulation of PaLCuCNV in the whiteflies was positively associated with its efficiency of transmitting the virus. Altogether, these findings indicate that MEAM1 is the most efficient vector for PaLCuCNV in the four species of whiteflies, and suggest that risks of PaLCuCNV pandemics are high in regions where MEAM1 occurs.

  11. Enterobacter tabaci sp. nov., a novel member of the genus Enterobacter isolated from a tobacco stem.

    PubMed

    Duan, Yan-Qing; Zhou, Xing-Kui; Di-Yan, Li; Li, Qing-Qing; Dang, Li-Zhi; Zhang, Yong-Guang; Qiu, Li-Hong; Nimaichand, Salam; Li, Wen-Jun

    2015-11-01

    A Gram-stain negative, motile, rod-shaped bacterium, designated strain YIM Hb-3(T), was isolated from the stem of a tobacco plant. The strain was observed to form convex, circular and yellow-colored colonies. The predominant respiratory quinone was identified as Q-8. The major fatty acids (>5%) detected were C(16:1)ω7c and/or C(16:1)ω6c (summed feature 3), C(16:0), C(17:0)cyclo, C(18:1)ω7c and/or C(18:1)ω6c (summed feature 8), C(14:0)3-OH and/or iso-C(16:1)I (summed feature 2), C(14:0) and C(12:0). The genomic DNA G+C content was determined to be 54.8 mol%. Phylogenetic trees based on 16S rRNA gene sequences and multilocus sequence analysis showed that strain YIM Hb-3(T) had the closest phylogenetic relationship with Enterobacter mori LMG 25706(T). DNA-DNA relatedness value between strain YIM Hb-3(T) and E. mori LMG 25706(T) was 46.9 ± 3.8%. On the basis of phenotypic and chemotaxonomic data, phylogenetic analysis, and DNA-DNA relatedness value, strain YIM Hb-3(T) is considered to represent a novel species of the genus Enterobacter, for which the name Enterobacter tabaci sp. nov. is proposed. The type strain is YIM Hb-3(T) (=KACC 17832(T) =KCTC 42694(T)).

  12. Virus infection of a weed increases vector attraction to and vector fitness on the weed.

    PubMed

    Chen, Gong; Pan, Huipeng; Xie, Wen; Wang, Shaoli; Wu, Qingjun; Fang, Yong; Shi, Xiaobin; Zhang, Youjun

    2013-01-01

    Weeds are important in the ecology of field crops, and when crops are harvested, weeds often become the main hosts for plant viruses and their insect vectors. Few studies, however, have examined the relationships between plant viruses, vectors, and weeds. Here, we investigated how infection of the weed Datura stramonium L. by tomato yellow leaf curl virus (TYLCV) affects the host preference and performance of the TYLCV vector, Bemisia tabaci (Gennadius) Q. The results of a choice experiment indicated that B. tabaci Q preferentially settled and oviposited on TYLCV-infected plants rather than on healthy plants. In addition, B. tabaci Q performed better on TYLCV-infected plants than on healthy plants. These results demonstrate that TYLCV is indirectly mutualistic to B. tabaci Q. The mutually beneficial interaction between TYLCV and B. tabaci Q may help explain the concurrent outbreaks of TYLCV and B. tabaci Q in China.

  13. Genetic networking of the Bemisia tabaci cryptic species complex reveals pattern of biological invasions.

    PubMed

    De Barro, Paul; Ahmed, Muhammad Z

    2011-01-01

    A challenge within the context of cryptic species is the delimitation of individual species within the complex. Statistical parsimony network analytics offers the opportunity to explore limits in situations where there are insufficient species-specific morphological characters to separate taxa. The results also enable us to explore the spread in taxa that have invaded globally. Using a 657 bp portion of mitochondrial cytochrome oxidase 1 from 352 unique haplotypes belonging to the Bemisia tabaci cryptic species complex, the analysis revealed 28 networks plus 7 unconnected individual haplotypes. Of the networks, 24 corresponded to the putative species identified using the rule set devised by Dinsdale et al. (2010). Only two species proposed in Dinsdale et al. (2010) departed substantially from the structure suggested by the analysis. The analysis of the two invasive members of the complex, Mediterranean (MED) and Middle East - Asia Minor 1 (MEAM1), showed that in both cases only a small number of haplotypes represent the majority that have spread beyond the home range; one MEAM1 and three MED haplotypes account for >80% of the GenBank records. Israel is a possible source of the globally invasive MEAM1 whereas MED has two possible sources. The first is the eastern Mediterranean which has invaded only the USA, primarily Florida and to a lesser extent California. The second are western Mediterranean haplotypes that have spread to the USA, Asia and South America. The structure for MED supports two home range distributions, a Sub-Saharan range and a Mediterranean range. The MEAM1 network supports the Middle East - Asia Minor region. The network analyses show a high level of congruence with the species identified in a previous phylogenetic analysis. The analysis of the two globally invasive members of the complex support the view that global invasion often involve very small portions of the available genetic diversity.

  14. Detection of resistance, cross-resistance, and stability of resistance to new chemistry insecticides in Bemisia tabaci (Homoptera: Aleyrodidae).

    PubMed

    Basit, Muhammad; Saeed, Shafqat; Saleem, Mushtaq Ahmad; Denholm, Ian; Shah, Maqbool

    2013-06-01

    Resistance levels in whitefly, Bemisia tabaci (Gennadius) collections from cotton and sunflower (up to four districts) for five neonicotinoids and two insect growth regulators (IGRs) were investigated for two consecutive years. Based on the LC50(s), all collections showed slight to moderate levels of resistance for the tested insecticides compared with the laboratory susceptible population. The data also indicated that cotton and sunflower collections had similar resistance levels. In comparison (four collections), Vehari collections showed higher resistance for acetamiprid, thiacloprid, and nitenpyram compared with those of others. Average resistance ratios for acetamiprid, thiacloprid, and nitenpyram ranged from 5- to 13-, 4- to 8-, and 9- to 13-fold, respectively. Multan and Vehari collections also exhibited moderate levels (9- to 16-fold) of resistance to buprofezin. Furthermore, toxicity of neonicotinoids against immature stages was equal to that of insect growth regulators. The data also suggested that resistance in the field populations was stable. After selection for four generations with bifenthrin (G1 to G4), resistance to bifenthrin increased to 14-fold compared with the laboratory susceptible population. Selection also increased resistance to fenpropathrin, lambdacyhalothrin, imidacloprid, acetamiprid, and diafenthuron. Cross-resistance and stability of resistance in the field populations is of some concern. Rotation of insecticides having no cross-resistance and targeting the control against immature stages may control the resistant insects, simultaneously reducing the selection pressure imposed.

  15. Molecular characterizations of DNA methyltransferase 3 and its roles in temperature tolerance in the whitefly, Bemisia tabaci Mediterranean.

    PubMed

    Dai, T-M; Lü, Z-C; Wang, Y-S; Liu, W-X; Hong, X-Y; Wan, F-H

    2018-02-01

    The Bemisia tabaci Mediterranean (MED) cryptic species is an invasive pest, distributed worldwide, with high ecological adaptability and thermotolerance. DNA methylation (a reversible chromatin modification) is one possible change that may occur within an organism subjected to environmental stress. To assess the effects of temperature stress on DNA methyltransferase 3 (Dnmt3) in MED, we cloned and sequenced BtDnmt3 and identified its functions in response to high and low temperatures. The full-length cDNA of BtDnmt3 was 3913 bp, with an open reading frame of 1962 bp, encoding a 73.89 kDa protein. In situ hybridization showed that BtDnmt3 was expressed mainly in the posterior region. BtDnmt3 messenger RNA expression levels were significantly down-regulated after exposure to heat shock and significantly up-regulated after exposure to cold shock. Furthermore, after feeding on double-stranded RNA specific for BtDnmt3, both heat resistance and cold resistance were significantly decreased, suggesting that BtDnmt3 is associated with thermal stress response and indicating a differential response to high- and low-temperature stress in MED. Together, these results highlight a potential role for DNA methylation in thermal resistance, which is a process important to successful invasion and colonization of an alien species in various environments. © 2017 The Royal Entomological Society.

  16. Spectral separability and mapping potential of cassava leaf damage symptoms caused by whiteflies (Bemisia tabaci)

    PubMed Central

    De Barro, Paul; Newnham, Glenn J; Kalyebi, Andrew; Macfadyen, Sarina; Malthus, Tim J

    2017-01-01

    Abstract BACKGROUND This study examines whether leaf spectra can be used to measure damage to cassava plants from whitefly (Bemisia tabaci), and the potential to translate measurements from leaf to landscape scale in eastern Africa. Symptoms of the cassava brown streak disease (CBSD) and cassava mosaic disease (CMD) viruses, and sooty mould (SM) blackening of lower leaves from whiteflies feeding on the upper leaves, were measured at the leaf scale with a high‐resolution spectroradiometer and a single photon avalanche diode (SPAD) meter, which retrieves relative chlorophyll concentration. Spectral measurements were compared to the five‐level visual scores used to assess the severity of each of the three damaging agents in the field, and also to leaf chemistry data. RESULTS Leaves exhibiting severe CBSD and CMD were spectrally indistinguishable from leaves without any symptoms. Severe SM was spectrally distinctive but is likely to be difficult to map because of its occurrence in the lower crown. SPAD measurements were highly correlated with most foliar chemistry measurements and field scores of disease severity. Regression models between simulated Sentinel 2 bands, field scores and SPAD measurements were strongest using wavelengths with high importance weightings in random forest models. CONCLUSION SPAD measurements are highly correlated to many foliar chemistry parameters, and should be considered for use in mapping disease severity over larger areas. Remaining challenges for mapping relate to the subtle expression of symptoms, the spatial distribution of disease severity within fields, and the small size and complex structure of the cassava fields themselves. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. PMID:28851022

  17. Diurnal activity of four species of thrips (Thysanoptera: Thripidae) and efficiencies of three nondestructive sampling techniques for thrips in mango inflorescences.

    PubMed

    Aliakbarpour, H; Rawi, Che Salmah Md

    2010-06-01

    Thrips cause considerable economic loss to mango, Mangifera indica L., in Penang, Malaysia. Three nondestructive sampling techniques--shaking mango panicles over a moist plastic tray, washing the panicles with ethanol, and immobilization of thrips by using CO2--were evaluated for their precision to determine the most effective technique to capture mango flower thrips (Thysanoptera: Thripidae) in an orchard located at Balik Pulau, Penang, Malaysia, during two flowering seasons from December 2008 to February 2009 and from August to September 2009. The efficiency of each of the three sampling techniques was compared with absolute population counts on whole panicles as a reference. Diurnal flight activity of thrips species was assessed using yellow sticky traps. All three sampling methods and sticky traps were used at two hourly intervals from 0800 to 1800 hours to get insight into diurnal periodicity of thrips abundance in the orchard. Based on pooled data for the two seasons, the CO2 method was the most efficient procedure extracting 80.7% adults and 74.5% larvae. The CO2 method had the lowest relative variation and was the most accurate procedure compared with the absolute method as shown by regression analysis. All collection techniques showed that the numbers of all thrips species in mango panicles increased after 0800 hours, reaching a peak between 1200 and 1400 hours. Adults thrips captured on the sticky traps were the most abundant between 0800-1000 and 1400-1600 hours. According to results of this study, the CO2 method is recommended for sampling of thrips in the field. It is a nondestructive sampling procedure that neither damages flowers nor diminishes fruit production. Management of thrips populations in mango orchards with insecticides would be more effectively carried out during their peak population abundance on the flower panicles at midday to 1400 hours.

  18. Postharvest control of western flower thrips (Thysanoptera: Thripidae) and California red scale (Hemiptera: Diaspididae) with ethyl formate and its impact on citrus fruit quality.

    PubMed

    Pupin, Francine; Bikoba, Veronique; Biasi, William B; Pedroso, Gabriel M; Ouyang, Yuling; Grafton-Cardwell, Elizabeth E; Mitcham, Elizabeth J

    2013-12-01

    The postharvest control of arthropod pests is a challenge that the California citrus industry must overcome when exporting fruit overseas. Currently, methyl bromide fumigation is used to control postharvest pests on exported citrus, but it may soon be unavailable because of use restrictions and cost of this health-hazard ozone-depleting chemical. Ethyl formate is a natural plant volatile and possible alternative to methyl bromide in postharvest insect control. The objectives of this study were 1) to evaluate the mortality of third instar California red scale [Aonidiella aurantii (Maskell)] (Hemiptera: Diaspididae) and adult western flower thrips [Frankliniella occidentalis (Pergande)] (Thysanoptera: Thripidae) under a wide range of ethyl formate concentrations, 2) to determine the ethyl formate concentration required to reach a Probit 9 level of control for both pests, and 3) to test the effects of ethyl formate fumigation on the quality of navel oranges [Citrus sinensis (L.) Osbeck] and lemons [Citrus limon (L.) Burman f.] at 24 h after fumigation, and at different time periods to simulate shipping plus storage (5 wk at 5 degrees C), and shipping, storage, handling, and shelf-life (5 wk at 5 degrees C, plus 5 d at 15 degrees C, and 2 d at 20 degrees C). The results indicate that ethyl formate is a promising alternative to methyl bromide for the California citrus industry, because of successful control of adult western flower thips and third instar California red scale and no deleterious effect on fruit quality at any of the evaluated periods and quality parameters.

  19. Fundamental host range of Pseudophilothrips ichini s.l. (Thysanoptera: Phlaeothripidae): a candidate biological control agent of Schinus terebinthifolius (Sapindales: Anacardiaceae) in the United States.

    PubMed

    Cuda, J P; Medal, J C; Gillmore, J L; Habeck, D H; Pedrosa-Macedo, J H

    2009-12-01

    Schinus terebinthifolius Raddi (Sapindales: Anacardiaceae) is a non-native perennial woody plant that is one of the most invasive weeds in Florida, Hawaii, and more recently California and Texas. This plant was introduced into Florida from South America as a landscape ornamental in the late 19th century, eventually escaped cultivation, and now dominates entire ecosystems in south-central Florida. Recent DNA studies have confirmed two separate introductions of S. terebinthifolius in Florida, and there is evidence of hybridization. A thrips, Pseudophilothrips ichini s.l. (Hood) (Thysanoptera: Phlaeothripidae), is commonly found attacking shoots and flowers of S. terebinthifolius in Brazil. Immatures and occasionally adults form large aggregations on young terminal growth (stems and leaves) of the plant. Feeding damage by P. ichini s.l. frequently kills new shoots, which reduces vigor and restricts growth of S. terebinthifolius. Greenhouse and laboratory host range tests with 46 plant species in 18 families and 10 orders were conducted in Paraná, Brazil, and Florida. Results of no-choice, paired-choice, and multiple-choice tests indicated that P. ichini s.l. is capable of reproducing only on S. terebinthifolius and possibly Schinus molle L., an ornamental introduced into California from Peru that has escaped cultivation and is considered invasive. Our results showed that P. ichini s.l. posed minimal risk to mature S. molle plants or the Florida native Metopium toxiferum L. Krug and Urb. In May 2007, the federal interagency Technical Advisory Group for Biological Control Agents of Weeds (TAG) concluded P. ichini s.l. was sufficiently host specific to recommend its release from quarantine.

  20. Spectral separability and mapping potential of cassava leaf damage symptoms caused by whiteflies (Bemisia tabaci).

    PubMed

    Sims, Neil C; De Barro, Paul; Newnham, Glenn J; Kalyebi, Andrew; Macfadyen, Sarina; Malthus, Tim J

    2018-01-01

    This study examines whether leaf spectra can be used to measure damage to cassava plants from whitefly (Bemisia tabaci), and the potential to translate measurements from leaf to landscape scale in eastern Africa. Symptoms of the cassava brown streak disease (CBSD) and cassava mosaic disease (CMD) viruses, and sooty mould (SM) blackening of lower leaves from whiteflies feeding on the upper leaves, were measured at the leaf scale with a high-resolution spectroradiometer and a single photon avalanche diode (SPAD) meter, which retrieves relative chlorophyll concentration. Spectral measurements were compared to the five-level visual scores used to assess the severity of each of the three damaging agents in the field, and also to leaf chemistry data. Leaves exhibiting severe CBSD and CMD were spectrally indistinguishable from leaves without any symptoms. Severe SM was spectrally distinctive but is likely to be difficult to map because of its occurrence in the lower crown. SPAD measurements were highly correlated with most foliar chemistry measurements and field scores of disease severity. Regression models between simulated Sentinel 2 bands, field scores and SPAD measurements were strongest using wavelengths with high importance weightings in random forest models. SPAD measurements are highly correlated to many foliar chemistry parameters, and should be considered for use in mapping disease severity over larger areas. Remaining challenges for mapping relate to the subtle expression of symptoms, the spatial distribution of disease severity within fields, and the small size and complex structure of the cassava fields themselves. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

  1. Genetics Home Reference: hepatic veno-occlusive disease with immunodeficiency

    MedlinePlus

    ... Donald JA, Kirk EP, Ziegler JB, Salzer U, McDonald GB, Wong M, Lindeman R, Buckley MF. Mutations ... of Medicine Lister Hill National Center for Biomedical Communications 8600 Rockville Pike, Bethesda, MD 20894, USA HONCode ...

  2. Thiamethoxam resistance selected in the western flower thrips Frankliniella occidentalis (Thysanoptera: Thripidae): cross-resistance patterns, possible biochemical mechanisms and fitness costs analysis.

    PubMed

    Gao, Cong-Fen; Ma, Shao-Zhi; Shan, Cai-Hui; Wu, Shun-Fan

    2014-09-01

    The western flower thrips (WFT) Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), an important pest of various crops in the world, has invaded China since 2003. To understand the risks and to determine possible mechanisms of resistance to thiamethoxam in WFT, a resistant strain was selected under the laboratory conditions. Cross-resistance and the possible biochemical resistance mechanisms were investigated in this study. A 15.1-fold thiamethoxam-resistant WFT strain (TH-R) was established after selection for 55 generations. Compared with the susceptible strain (TH-S), the selected TH-R strain showed extremely high level cross-resistance to imidaclothiz (392.1-fold) and low level cross-resistance to dinotefuran (5.7-fold), acetamiprid (2.9-fold) and emamectin benzoate (2.1-fold), respectively. No cross-resistance to other fourteen insecticides was detected. Synergism tests showed that piperonyl butoxide (PBO) and triphenyl phosphate (TPP) produced a high synergism of thiamethoxam effects in the TH-R strain (2.6- and 2.6-fold respectively). However, diethyl maleate (DEM) did not act synergistically with thiamethoxam. Biochemical assays showed that mixed function oxidase (MFO) activities and carboxylesterase (CarE) activity of the TH-R strain were 2.8- and 1.5-fold higher than that of the TH-S strain, respectively. When compared with the TH-S strain, the TH-R strain had a relative fitness of 0.64. The results show that WFT develops resistance to thiamethoxam after continuous application and thiamethoxam resistance had considerable fitness costs in the WFT. It appears that enhanced metabolism mediated by cytochrome P450 monooxygenases and CarE was a major mechanism for thiamethoxam resistance in the WFT. The use of cross-resistance insecticides, including imidaclothiz and dinotefuran, should be avoided for sustainable resistance management. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Transcriptome analysis of the whitefly, Bemisia tabaci MEAM1 during feeding on tomato infected with the crinivirus, Tomato chlorosis virus, identifies a temporal shift in gene expression and differential regulation of novel orphan genes.

    PubMed

    Kaur, Navneet; Chen, Wenbo; Zheng, Yi; Hasegawa, Daniel K; Ling, Kai-Shu; Fei, Zhangjun; Wintermantel, William M

    2017-05-11

    Whiteflies threaten agricultural crop production worldwide, are polyphagous in nature, and transmit hundreds of plant viruses. Little is known how whitefly gene expression is altered due to feeding on plants infected with a semipersistently transmitted virus. Tomato chlorosis virus (ToCV; genus Crinivirus, family Closteroviridae) is transmitted by the whitefly (Bemisia tabaci) in a semipersistent manner and infects several globally important agricultural and ornamental crops, including tomato. To determine changes in global gene regulation in whiteflies after feeding on tomato plants infected with a crinivirus (ToCV), comparative transcriptomic analysis was performed using RNA-Seq on whitefly (Bemisia tabaci MEAM1) populations after 24, 48, and 72 h acquisition access periods on either ToCV-infected or uninfected tomatoes. Significant differences in gene expression were detected between whiteflies fed on ToCV-infected tomato and those fed on uninfected tomato among the three feeding time periods: 447 up-regulated and 542 down-regulated at 24 h, 4 up-regulated and 7 down-regulated at 48 h, and 50 up-regulated and 160 down-regulated at 72 h. Analysis revealed differential regulation of genes associated with metabolic pathways, signal transduction, transport and catabolism, receptors, glucose transporters, α-glucosidases, and the uric acid pathway in whiteflies fed on ToCV-infected tomatoes, as well as an abundance of differentially regulated novel orphan genes. Results demonstrate for the first time, a specific and temporally regulated response by the whitefly to feeding on a host plant infected with a semipersistently transmitted virus, and advance the understanding of the whitefly vector-virus interactions that facilitate virus transmission. Whitefly transmission of semipersistent viruses is believed to require specific interactions between the virus and its vector that allow binding of virus particles to factors within whitefly mouthparts. Results provide a

  4. Selection and validation of reference genes for qRT-PCR analysis during biological invasions: The thermal adaptability of Bemisia tabaci MED.

    PubMed

    Dai, Tian-Mei; Lü, Zhi-Chuang; Liu, Wan-Xue; Wan, Fang-Hao

    2017-01-01

    The Bemisia tabaci Mediterranean (MED) cryptic species has been rapidly invading to most parts of the world owing to its strong ecological adaptability, which is considered as a model insect for stress tolerance studies under rapidly changing environments. Selection of a suitable reference gene for quantitative stress-responsive gene expression analysis based on qRT-PCR is critical for elaborating the molecular mechanisms of thermotolerance. To obtain accurate and reliable normalization data in MED, eight candidate reference genes (β-act, GAPDH, β-tub, EF1-α, GST, 18S, RPL13A and α-tub) were examined under various thermal stresses for varied time periods by using geNorm, NormFinder and BestKeeper algorithms, respectively. Our results revealed that β-tub and EF1-α were the best reference genes across all sample sets. On the other hand, 18S and GADPH showed the least stability for all the samples studied. β-act was proved to be highly stable only in case of short-term thermal stresses. To our knowledge this was the first comprehensive report on validation of reference genes under varying temperature stresses in MED. The study could expedite particular discovery of thermotolerance genes in MED. Further, the present results can form the basis of further research on suitable reference genes in this invasive insect and will facilitate transcript profiling in other invasive insects.

  5. Host-parasitoid interactions relating to penetration of the whitefly, Bemisia tabaci, by the parasitoid wasp, Eretmocerus mundus

    PubMed Central

    Gelman, Dale B.; Gerling, Dan; Blackburn, Michael A.

    2005-01-01

    It has been reported that the aphelinid wasp Eertmocerus mundus parasitizes all four nymphal instars of the sweet potato whitefly, Bemisia tabaci (Biotype B), with 3rd instars being the preferred hosts. The parasitoid lays its egg on the leaf underneath the host nymph. First instars hatch and later penetrate the whitefly. Previous studies have shown that the initiation of parasitoid penetration induces the host to form a cellular capsule around the parasitoid. As described here, females never oviposited once the 4th instar whitefly nymph had initiated adult development. First instar E. mundus larvae were observed under 2nd, 3rd and 4th instar whitefly nymphs, however, penetration did not occur until the whitefly had reached the 4th instar. The non-penetrating E. mundus larva almost always induced permanent developmental arrest in its 4th instar whitefly host and also caused a reduction in whole body host ecdysteroid titers. Therefore, unless there is a peak in molting hormone titer in the area local to penetration, it appears that the induction of capsule formation is not due to an increase in ecdysteroid titer. As the capsule formed around the penetrating parasitoid, host epidermal cells multiplied and became cuboidal and columnar, and relatively thick layers of new cuticle were deposited within the developing capsule, particularly near its ventral opening. The newly formed host cuticle was thinner in the dorsal part of the capsule and appeared to be absent at its apex. These results provide new information regarding the timing and dynamics of parasitoid oviposition and egg hatch as related to larval penetration, parasitoid-induced changes in whitefly development, molting hormone titers and the process of capsule formation. PMID:17119628

  6. Pesticide-mediated interspecific competition between local and invasive thrips pests.

    PubMed

    Zhao, Xueyin; Reitz, Stuart R; Yuan, Huiguo; Lei, Zhongren; Paini, Dean Ronald; Gao, Yulin

    2017-01-13

    Competitive interactions between species can be mitigated or even reversed in the presence of anthropogenic influences. The thrips species Frankliniella occidentalis and Thrips tabaci are highly invasive and damaging agricultural pests throughout the world. Where the species co-occur, one species tends to eventually predominate over the other. Avermectin and beta-cypermethrin are commonly used insecticides to manage thrips in China, and laboratory bioassays demonstrated that F. occidentalis is significantly less susceptible than T. tabaci to these insecticides. In laboratory cage trials in which both species were exposed to insecticide treated cabbage plants, F. occidentalis became the predominant species. In contrast, T. tabaci completely displaced F. occidentalis on plants that were not treated with insecticides. In field trials, the species co-existed on cabbage before insecticide treatments began, but with T. tabaci being the predominant species. Following application of avermectin or beta-cypermethrin, F. occidentalis became the predominant species, while in plots not treated with insecticides, T. tabaci remained the predominant species. These results indicate that T. tabaci is an intrinsically superior competitor to F. occidentalis, but its competitive advantage can be counteracted through differential susceptibilities of the species to insecticides. These results further demonstrate the importance of external factors, such as insecticide applications, in mediating the outcome of interspecific interactions and produce rapid unanticipated shifts in the demographics of pest complexes.

  7. Pesticide-mediated interspecific competition between local and invasive thrips pests

    PubMed Central

    Zhao, Xueyin; Reitz, Stuart R.; Yuan, Huiguo; Lei, Zhongren; Paini, Dean Ronald; Gao, Yulin

    2017-01-01

    Competitive interactions between species can be mitigated or even reversed in the presence of anthropogenic influences. The thrips species Frankliniella occidentalis and Thrips tabaci are highly invasive and damaging agricultural pests throughout the world. Where the species co-occur, one species tends to eventually predominate over the other. Avermectin and beta-cypermethrin are commonly used insecticides to manage thrips in China, and laboratory bioassays demonstrated that F. occidentalis is significantly less susceptible than T. tabaci to these insecticides. In laboratory cage trials in which both species were exposed to insecticide treated cabbage plants, F. occidentalis became the predominant species. In contrast, T. tabaci completely displaced F. occidentalis on plants that were not treated with insecticides. In field trials, the species co-existed on cabbage before insecticide treatments began, but with T. tabaci being the predominant species. Following application of avermectin or beta-cypermethrin, F. occidentalis became the predominant species, while in plots not treated with insecticides, T. tabaci remained the predominant species. These results indicate that T. tabaci is an intrinsically superior competitor to F. occidentalis, but its competitive advantage can be counteracted through differential susceptibilities of the species to insecticides. These results further demonstrate the importance of external factors, such as insecticide applications, in mediating the outcome of interspecific interactions and produce rapid unanticipated shifts in the demographics of pest complexes. PMID:28084404

  8. Summer weeds as hosts for Frankliniella occidentalis and Frankliniella fusca (Thysanoptera: Thripidae) and as reservoirs for tomato spotted wilt Tospovirus in North Carolina.

    PubMed

    Kahn, Noah D; Walgenbach, J F; Kennedy, G G

    2005-12-01

    In North Carolina, Tomato spotted wilt tospovirus (family Bunyaviridae, genus Tospovirus, TSWV) is vectored primarily by the tobacco thrips, Frankliniella fusca (Hinds), and the western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). TSWV overwinters in winter annual weeds from which it is spread to susceptible crops in spring. Because most susceptible crops are destroyed after harvest before winter weeds emerge in the fall, infected summer weeds are thought to be the principal source for spread of TSWV to winter annual weeds in fall. A survey of summer weeds associated with TSWV-susceptible crops in the coastal plain of North Carolina conducted between May and October revealed that relatively few species were commonly infected with TSWV and supported populations of F. fusca or F. occidentalis. F. occidentalis made up > 75% of vector species collected from 15 summer weed species during 2002. The number of F. occidentalis and F. fusca immatures collected from plant samples varied significantly among plant species. Ipomoea purpurea (L.) Roth, Mollugo verticillata L., Cassia obtusifolia L., and Amaranthus palmeri S. Wats supported the largest numbers of immature F. occidentalis. Richardia scabra L., M. verticillata, and Ipomoea hederacea (L.) supported the largest numbers of F. fusca immatures. TSWV was present at 16 of 17 locations, and naturally occurring infections were found in 14 of 29 weed species tested. Five of the TSWV-infected species have not previously been reported as hosts of TSWV (A. palmeri, Solidago altissima L., Ipomoea lacunosa L., I. purpurea, and Phytolacca americana L.). Estimated rates of infection were highest in I. purpurea (6.8%), M. verticillata (5.3%), and I. hederacea (1.9%). When both the incidence of infection by TSWV and the populations of F. occidentalis and F. fusca associated with each weed species are considered, the following summer weed species have the potential to act as significant sources for

  9. Effects of Three Insect Growth Regulators on Encarsia formosa (Hymenoptera: Aphelinidae), an Endoparasitoid of Bemisia tabaci (Hemiptera: Aleyrodidae).

    PubMed

    Wang, Q L; Liu, T-X

    2016-12-01

    Insect growth regulators (IGRs) disrupt the normal activity of the endocrine or hormone system of insects, affecting the development, reproduction, or metamorphosis of the target insects, and normally causing less detrimental effects to beneficial insects. The effects of three IGRs (pyriproxyfen, fenoxycarb, and buprofezin) on Encarsia formosa Gahan, an endoparasitoid of whiteflies, were determined using B. tabaci as a host. We assessed the effects of the IGRs on parasitoid's larval development, pupation, emergence, and contact effects of the dry residues on plant leaf and glass vial surface on adult mortality and parasitism. When the three IGRs were applied at larval stage, no or few larvae pupated in the pyriproxyfen treatments and the highest concentration of fenoxycarb, and a majority of larvae pupated in the buprofezin treatments; of those pupated, 62.3-88.1% became adults. When the IGRs were applied at the pupal stage, 2.3-17.5% developed to adults in the pyriproxyfen treatments, 59.7-89.0% in the fenoxycarb treatments, and 58.4-83.6% in the buprofezin treatments. The leaf residues of the IGRs had no appreciable effects on adults, whereas the residues on glass vial caused significantly lower adult survival than on plant leaves. The residues of pyriproxyfen and fenoxycarb slightly reduced parasitism as compared with buprofezin and controls. However, the rates of parasitoids that became adults were significantly lower, especially in the pyriproxyfen treatments. According to the standards of International Organization of Biological Control (IOBC), pyriproxyfen was harmful, while fenoxycarb and buprofezin were slightly or moderately harmful to larvae and harmless to E. formosa pupae. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  10. A Bibliography of the Personal Software Process (PSP) and the Team Software Process (TSP)

    DTIC Science & Technology

    2009-10-01

    Postmortem.‖ Proceedings of the TSP Symposium (September 2007). http://www.sei.cmu.edu/tspsymposium/ Rickets , Chris; Lindeman, Robert; & Hodgins, Brad... Rickets , Chris A. ―A TSP Software Maintenance Life Cycle.‖ CrossTalk (March 2005). Rozanc, I. & Mahnic, V. ―Teaching Software Quality with Emphasis on PSP

  11. Former Presidents Reflect on 20 Years of NCSSSMST

    ERIC Educational Resources Information Center

    Templin, Elizabeth, Comp.

    2008-01-01

    The Consortium celebrated its 20th anniversary at the 2008 Professional Conference in Dallas, Texas in February 2008. Founding president Stephanie Pace Marshall and former presidents Joan Barber, Janet Hugo, Ron Laugen, Cheryl Lindeman, Dennis Lundgren, and Betty Stapp responded to questions about the organization and their involvement with…

  12. Counselors' Perceived Person-Environment Fit and Career Satisfaction

    ERIC Educational Resources Information Center

    Rehfuss, Mark C.; Gambrell, Crista E.; Meyer, Dixie

    2012-01-01

    This correlational study examined the relationship between career satisfaction and person-organization, demands-abilities, and needs-supplies fit with counselors (N = 464) using the Perceived Job Fit instrument (Cable & DeRue, 2002) and a scale of career satisfaction adapted from the Adult Career Concerns Inventory (Super, Thompson, Lindeman,…

  13. Practice-Based Learning and Improvement: A Dream that Can Become a Reality

    ERIC Educational Resources Information Center

    Manning, Phil R.

    2003-01-01

    Systematically enhancing learning from experience (practice-based learning) dominates the teachings of Sir Willian Osler and adult learning theorists such as Eduard Lindeman, Malcolm Knowles, and Cyril Houle. Because of time constraints, most physicians have not implemented methods that systematically facilitate learning from day-to-day work, but…

  14. Photoinhibition and photoinhibition-like damage to the photosynthetic apparatus in tobacco leaves induced by pseudomonas syringae pv. Tabaci under light and dark conditions.

    PubMed

    Cheng, Dan-Dan; Zhang, Zi-Shan; Sun, Xing-Bin; Zhao, Min; Sun, Guang-Yu; Chow, Wah Soon

    2016-01-25

    Pseudomonas syringae pv. tabaci (Pst), which is the pathogen responsible for tobacco wildfire disease, has received considerable attention in recent years. The objective of this study was to clarify the responses of photosystem I (PSI) and photosystem II (PSII) to Pst infection in tobacco leaves. The net photosynthetic rate (Pn) and carboxylation efficiency (CE) were inhibited by Pst infection. The normalized relative variable fluorescence at the K step (W k) and the relative variable fluorescence at the J step (V J) increased while the maximal quantum yield of PSII (F v/F m) and the density of Q A-reducing PSII reaction centers per cross section (RC/CSm) decreased, indicating that the reaction centers, and the donor and acceptor sides of PSII were all severely damaged after Pst infection. The PSI activity decreased as the infection progressed. Furthermore, we observed a considerable overall degradation of PsbO, D1, PsaA proteins and an over-accumulation of reactive oxygen species (ROS). Photoinhibition and photoinhibition-like damage were observed under light and dark conditions, respectively, after Pst infection of tobacco leaves. The damage was greater in the dark. ROS over-accumulation was not the primary cause of the photoinhibition and photoinhibition-like damage. The PsbO, D1 and PsaA proteins appear to be the targets during Pst infection under light and dark conditions.

  15. Higher-level phylogeny of paraneopteran insects inferred from mitochondrial genome sequences

    PubMed Central

    Li, Hu; Shao, Renfu; Song, Nan; Song, Fan; Jiang, Pei; Li, Zhihong; Cai, Wanzhi

    2015-01-01

    Mitochondrial (mt) genome data have been proven to be informative for animal phylogenetic studies but may also suffer from systematic errors, due to the effects of accelerated substitution rate and compositional heterogeneity. We analyzed the mt genomes of 25 insect species from the four paraneopteran orders, aiming to better understand how accelerated substitution rate and compositional heterogeneity affect the inferences of the higher-level phylogeny of this diverse group of hemimetabolous insects. We found substantial heterogeneity in base composition and contrasting rates in nucleotide substitution among these paraneopteran insects, which complicate the inference of higher-level phylogeny. The phylogenies inferred with concatenated sequences of mt genes using maximum likelihood and Bayesian methods and homogeneous models failed to recover Psocodea and Hemiptera as monophyletic groups but grouped, instead, the taxa that had accelerated substitution rates together, including Sternorrhyncha (a suborder of Hemiptera), Thysanoptera, Phthiraptera and Liposcelididae (a family of Psocoptera). Bayesian inference with nucleotide sequences and heterogeneous models (CAT and CAT + GTR), however, recovered Psocodea, Thysanoptera and Hemiptera each as a monophyletic group. Within Psocodea, Liposcelididae is more closely related to Phthiraptera than to other species of Psocoptera. Furthermore, Thysanoptera was recovered as the sister group to Hemiptera. PMID:25704094

  16. Continuing the Legacy: Democracy and Education Practice

    ERIC Educational Resources Information Center

    Jorgensen, Sara; Schwartz, Joni

    2012-01-01

    The American adult education and literacy movement in the early twentieth century had its roots deep in the study and practice of democracy (Ramdeholl, Giordani, Heaney, Yanow, 2010). From Lindeman, Dewey, Laubach, Horton, to Heaney and Brookfield, a persistent theme is the indispensable relationship between democracy and adult education. For…

  17. Differential gene expression in whitefly Bemisia tabaci-infested tomato (Solanum lycopersicum) plants at progressing developmental stages of the insect's life cycle.

    PubMed

    Estrada-Hernández, María Gloria; Valenzuela-Soto, José Humberto; Ibarra-Laclette, Enrique; Délano-Frier, John Paul

    2009-09-01

    A suppression-subtractive-hybridization (SSH) strategy was used to identify genes whose expression was modified in response to virus-free whitefly Bemisia tabaci (Bt, biotype A) infestation in tomato (Solanum lycopersicum) plants. Thus, forward and reverse SSH gene libraries were generated at four points in the whitefly's life cycle, namely at (1) 2 days (adult feeding and oviposition: phase I); (2) 7 days (mobile crawler stage: phase II); (3) 12 days (second to third instar nymphal transition: phase III) and (4) 18 days (fourth instar nymphal stage: phase IV). The 169 genes with altered expression (up and downregulated) that were identified in the eight generated SSH libraries, together with 75 additional genes that were selected on the basis of their involvement in resistance responses against phytofagous insects and pathogens, were printed on a Nexterion(®) Slide MPX 16 to monitor their pattern of expression at the above phases. The results indicated that Bt infestation in tomato led to distinctive phase-specific expression/repression patterns of several genes associated predominantly with photosynthesis, senescence, secondary metabolism and (a)biotic stress. Most of the gene expression modifications were detected in phase III, coinciding with intense larval feeding, whereas fewer changes were detected in phases I and IV. These results complement previously reported gene expression profiles in Bt-infested tomato and Arabidopisis, and support and expand the opinion that Bt infestation leads to the downregulation of specific defense responses in addition to those controlled by jasmonic acid. Copyright © Physiologia Plantarum 2009.

  18. Thermotolerance and Heat-Shock Protein Gene Expression Patterns in Bemisia tabaci (Hemiptera: Aleyrodidae) Mediterranean in Relation to Developmental Stage.

    PubMed

    Jiang, Rui; Qi, Lan-Da; Du, Yu-Zhou; Li, Yuan-Xi

    2017-10-01

    Temperature plays an important role in the growth, development, and geographic distribution of insects. There is convincing evidence that heat-shock proteins (HSPs) play important roles in helping organisms adapt to thermal stress. To better understand the physiological and ecological influence of thermal stress on the different development stages of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) Mediterranean species (MED), nymphs and adults were shocked with temperatures of 35, 38, and 41℃ for 1 and 2 h, respectively, and the survival rate, fecundity, and developmental duration were investigated in the laboratory. The expression levels of the hsp40, hsp70, and hsp90 genes were assessed using real-time PCR. The results indicate that the survival rates of the nymphs and adults decreased with increased temperature. A 2-h heat shock at 41℃ induced a significant reduction in fecundity in adults and an increase in developmental duration in young nymphs. Hsp90 showed higher temperature responses to thermal stress than hsp40 or hsp70. The expression levels of the hsps in the adults were significantly down-regulated by a 2-h heat shock at 41℃ compared with that by a 1-h treatment. A significant decrease in the expression levels of the hsps also occurred in the adults when the temperature increased from 38 to 41℃ for the 2-h treatment, whereas no significant decrease occurred in the nymphs. Compared with previous studies, we provide some evidence indicating that MED has the potential to adapt to a wider temperature range than the Middle East-Asia Minor 1 species. © The Author 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  19. Light Suppresses Bacterial Population through the Accumulation of Hydrogen Peroxide in Tobacco Leaves Infected with Pseudomonas syringae pv. tabaci

    PubMed Central

    Cheng, Dan-Dan; Liu, Mei-Jun; Sun, Xing-Bin; Zhao, Min; Chow, Wah S.; Sun, Guang-Yu; Zhang, Zi-Shan; Hu, Yan-Bo

    2016-01-01

    Pseudomonas syringae pv. tabaci (Pst) is a hemibiotrophic bacterial pathogen responsible for tobacco wildfire disease. Although considerable research has been conducted on the tobacco plant’s tolerance to Pst, the role of light in the responses of the photosystems to Pst infection is poorly understood. This study aimed to elucidate the underlying mechanisms of the reduced photosystem damage in tobacco leaves due to Pst infection under light conditions. Compared to dark conditions, Pst infection under light conditions resulted in less chlorophyll degradation and a smaller decline in photosynthetic function. Although the maximal quantum yield of photosystem II (PSII) and the activity of the photosystem I (PSI) complex decreased as Pst infection progressed, damage to PSI and PSII after infection was reduced under light conditions compared to dark conditions. Pst was 17-fold more abundant in tobacco leaves under dark compared to light conditions at 3 days post inoculation (dpi). Additionally, H2O2 accumulated to a high level in tobacco leaves after Pst infection under light conditions; although to a lesser extent, H2O2 accumulation was also significant under dark conditions. Pretreatment with H2O2 alleviated chlorotic lesions and decreased Pst abundance in tobacco leaves at 3 dpi under dark conditions. MV pretreatment had the same effects under light conditions, whereas 3-(3,4-dichlorophenyl)-1,1-dimethylurea pretreatment aggravated chlorotic lesions and increased the Pst population. These results indicate that chlorotic symptoms and the size of the bacterial population are each negatively correlated with H2O2 accumulation. In other words, light appears to suppress the Pst population in tobacco leaves through the accumulation of H2O2 during infection. PMID:27148334

  20. Evaluating plant and plant oil repellency against the sweetpotato whitefly

    USDA-ARS?s Scientific Manuscript database

    The sweetpotato whitefly, Bemisia tabaci is a major insect pest of vegetables world-wide. We evaluated the effect of commercial plant oils – garlic oil, hot pepper wax, and mustard oil against B. tabaci. Cucumber plants served as the control. Additional treatments included no plants or oil (clear ai...

  1. The interaction of facility design with management goals.

    PubMed

    Lindeman, W E

    1991-01-01

    While medical groups have different goals based on their mission, size and market, they all seek to propagate and maintain a financially sound enterprise. Author William Lindeman, AIA, writes that a primary factor in achieving this goal is excellent facility design. While facility design is no guarantee for success, exceptionally poor design can make success all but impossible.

  2. Seasonal dynamics of thrips (Thrips tabaci) (Thysanoptera: Thripidae) transmitters of iris yellow spot virus: a serious viral pathogen of onion bulb and seed crops.

    PubMed

    Bag, Sudeep; Rondon, Silvia I; Druffel, Keri L; Riley, David G; Pappu, Hanu R

    2014-02-01

    Thrips-transmitted Iris yellow spot virus (IYSV) is an important economic constraint to the production of bulb and seed onion crops in the United States and many other parts of the world. Because the virus is exclusively spread by thrips, the ability to rapidly detect the virus in thrips vectors would facilitate studies on the role of thrips in virus epidemiology, and thus formulation of better vector management strategies. Using a polyclonal antiserum produced against the recombinant, Escherichia coli-expressed nonstructural protein coded by the small (S) RNA of IYSV, an enzyme linked immunosorbent assay was developed for detecting IYSV in individual as well as groups of adult thrips. The approach enabled estimating the proportion of potential thrips transmitters in a large number of field-collected thrips collected from field-grown onion plants. Availability of a practical and inexpensive test to identify viruliferous thrips would be useful in epidemiological studies to better understand the role of thrips vectors in outbreaks of this economically important virus of onion.

  3. Attraction of New Zealand flower thrips, Thrips obscuratus, to cis-jasmone, a volatile identified from Japanese honeysuckle flowers.

    PubMed

    El-Sayed, A M; Mitchell, V J; McLaren, G F; Manning, L M; Bunn, B; Suckling, D M

    2009-06-01

    This work was undertaken to identify floral compound(s) produced by honeysuckle flowers, Lonicera japonica (Thunberg), that mediate the attraction of New Zealand flower thrips Thrips obscuratus (Crawford). Volatiles were collected during the day and night and analyzed by gas chromatography-mass spectrometry (GC-MS) to determine their emission over these two periods. Nine compounds were identified in the headspace; the main compound was linalool, and the other compounds were germacrene D, E,E-alpha-farnesene, nerolidol, cis-jasmone, cis-3-hexenyl acetate, hexyl acetate, cis-hexenyl tiglate, and indole. There was a quantitative difference between day and night volatiles, with cis-3-hexenyl acetate, hexyl acetate, cis-hexenyl tiglate, and cis-jasmone emitted in higher amounts during the day compared to the night. When the compounds were tested individually in field trapping experiments, only cis-jasmone attracted New Zealand flower thrips in a significant number. In another field trapping experiment, cis-jasmone caught similar numbers of New Zealand flower thrips compared to a floral blend formulated to mimic the ratios of the compounds emitted during the day, while catch with the night-emitted floral blend was not significantly different from the control. Subsequently, two field trapping experiments were conducted to determine the optimal attraction dose for cis-jasmone, a range of 1-100 mg loaded onto a red rubber stopper was tested, and the highest catches were in traps baited with 100 mg loading. A higher range of 100-1000 mg loaded into polyethylene vials was tested, and the highest catch was in traps baited with 500 mg. In another experiment aimed at comparing the attraction efficacy of cis-jasmone with the two other known thrips attractants (ethyl nicotinate and p-anisaldehyde), ethyl nicotinate showed the highest trap catch followed by cis-jasmone. A smaller number of Thrips tabaci (Lindeman) was attracted to traps baited with cis-jasmone. These results

  4. Presence of Native Prey Does Not Divert Predation on Exotic Pests by Harmonia axyridis in Its Indigenous Range

    PubMed Central

    Zhang, Gui Fen; Lövei, Gábor L; Wu, Xia; Wan, Fang Hao

    2016-01-01

    In China, two invasive pests, Bemisia tabaci MEAM1 (Gennadius) and Frankliniella occidentalis (Pergande), often co-occur with the native pest, Aphis gossypii (Glover), on plants of Malvaceae and Cucurbitaceae. All three are preyed on by the native ladybird, Harmonia axyridis (Pallas); however, the native predator might be expected to prefer native prey to the exotic ones due to a shared evolutionary past. In order to clarify whether the presence of native prey affected the consumption of these two invasive species by the native predator, field-cage experiments were conducted. A duplex qPCR was used to simultaneously detect both non-native pests within the gut of the predator. H. axyridis readily accepted both invasive prey species, but preferred B. tabaci. With all three prey species available, H. axyridis consumption of B. tabaci was 39.3±2.2% greater than consumption of F. occidentalis. The presence of A. gossypii reduced (by 59.9% on B. tabaci, and by 60.6% on F. occidentalis), but did not stop predation on the two exotic prey when all three were present. The consumption of B. tabaci was similar whether it was alone or together with A. gossypii. However, the presence of aphids reduced predation on the invasive thrips. Thus, some invasive prey may be incorporated into the prey range of a native generalist predator even in the presence of preferred native prey. PMID:27391468

  5. Increased survival and prolonged longevity mainly contribute to the temperature-adaptive evolutionary strategy in invasive Bemisia tabaci (Hemiptera: Aleyrodidae) Middle East Asia Minor 1.

    PubMed

    Lü, Zhi-Chuang; Gao, Qing-Lei; Wan, Fang-Hao; Yu, Hao; Guo, Jian-Ying

    2014-10-15

    With increasing global climate change, analyses of stress-inducing conditions have important significance in ecological adaptation and the biological distribution of species. To reveal the difference in temperature-adaptive strategy between Turpan and Beijing populations of Bemisia tabaci (Gennadius) Middle East Asia Minor 1 (MEAM1) under high-temperature stress conditions, we compared thermal tolerance and life history traits between Beijing and Turpan populations of MEAM1 after exposure to different heat shock treatments for different times. The experimental design reflected the nature of heat stress conditions suffered by MEAM1. The results showed that eggs, red-eyed pupae, and adults of the Turpan population were more heat tolerant than those of the Beijing population under the same stress conditions. Additionally, it was found that longevity and F1 adult survival rate were significantly higher in the Turpan population than in the Beijing population after heat shock stress, but egg number and F1 female ratio were not significantly different between Turpan population and Beijing population. Overall, it was suggested that heat tolerance and longevity traits were the most relevant for climate characteristics and not reproductive traits, and improved heat tolerance and prolonged longevity were important adaptive strategies that helped MEAM1 to survive in harsh high-temperature conditions such as Turpan arid desert climate. The present results provided further insight into the modes of heat tolerance and the ways in which survival and longevity traits respond to environmental selection pressures. © The Author 2014. Published by Oxford University Press on behalf of the Entomological Society of America.

  6. Resistance Mechanisms to Chlorpyrifos and F392W Mutation Frequencies in the Acetylcholine Esterase Ace1 Allele of Field Populations of the Tobacco Whitefly, Bemisia tabaci in China

    PubMed Central

    Zhang, Ning-ning; Liu, Cai-feng; Yang, Fang; Dong, Shuang-lin; Han, Zhao-jun

    2012-01-01

    The tobacco whitefly B-biotype Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) is a worldwide pest of many crops. In China, chlorpyrifos has been used to control this insect for many years and is still being used despite the fact that some resistance has been reported. To combat resistance and maintain good control efficiency of chlorpyrifos, it is essential to understand resistance mechanisms. A chlorpyrifos resistant tobacco whitefly strain (NJ-R) and a susceptible strain (NJ-S) were derived from a field-collected population in Nanjing, China, and the resistance mechanisms were investigated. More than 30-fold resistance was achieved after selected by chlorpyrifos for 13 generations in the laboratory. However, the resistance dropped significantly to about 18-fold in only 4 generations without selection pressure. Biochemical assays indicated that increased esterase activity was responsible for this resistance, while acetylcholine esterase, glutathione S-transferase, and microsomal-O-demethylase played little or no role. F392W mutations in acel were prevalent in NJ-S and NJ-R strains and 6 field-collected populations of both B and Q-biotype from locations that cover a wide geographical area of China. These findings provide important information about tobacco whitefly chlorpyrifos resistance mechanisms and guidance to combat resistance and optimize use patterns of chlorpyrifos and other organophosphate and carbamate insecticides. PMID:22954331

  7. Comparative evaluation of two populations of Pseudophilothrips ichini as candidates for biological control of Brazilian peppertree

    USDA-ARS?s Scientific Manuscript database

    Brazilian peppertree, Schinus terebinthifolius Raddi (Sapindales: Anacardiaceae) is one of the worst invasive species in Florida. The thrips Pseudophilothrips ichini Hood (Thysanoptera: Phlaeothripidae) is being considered as a potential biological control agent of Brazilian peppertree. Two populati...

  8. Western flower thrips resistance to insecticides: detection, mechanisms, and management strategies

    USDA-ARS?s Scientific Manuscript database

    Insecticide resistance continues to be one of the most important issues facing agricultural production. The challenges in insecticide resistance and its management are exemplified by the situation with the western flower thrips Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). This ...

  9. Analyzing predation of hoverflies (Diptera: Syrphidae) in Mediterranean lettuce crops using molecular techniques

    USDA-ARS?s Scientific Manuscript database

    Hoverflies are generalist predators of a great variety of primary pests. Nasonovia ribisnigri (Mosley) (Hemiptera: Aphididae) and Frankliniella occidentalis (Thysanoptera: Thripidae) are two common pests in Mediterranean lettuce crops, where they occur alongside alternative prey (e.g., Collembola). ...

  10. Potential use of the fungus Beauveria bassiana against the western flower thrips Frankliniella occidentalis without reducing the effectiveness of its natural predator Orius sauteri (Hemiptera: Anthocoridae)

    USDA-ARS?s Scientific Manuscript database

    Orius sauteri (Poppius) (Hemiptera: Anthocoridae) is an important predator of western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). Orius sauteri would be directly exposed to the entomopathogenic fungus Beauveria bassiana (Bals.) Vuillemin in the field should the fu...

  11. MEASUREMENT OF TIME INTERVALS FOR TIME CORRELATED RADIOACTIVE DECAY

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lindeman, H.; Mornel, E.; Galil, U.

    1960-11-01

    The distribution of time intervals between successive counts was measured for radioactive decay in the thorium series. The measurements showed that the classical Marsden-Barratt law does not apply to this case of timecorrelated decay. They appeared, however, to be in agreement with the theory of Lindeman-Rosen, taking into account the fact that the counter receives only the radiation emitted in a solid angle near to 2 pi . (auth)

  12. Frankliniella occidentalis (Pergande) integrated pest management programs for fruiting vegetables in Florida

    USDA-ARS?s Scientific Manuscript database

    The spread of the western flower thrips Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) resulted in the worldwide destabilization of established integrated pest management programs for many crops. Efforts to control the pest and the thrips-vectored tospoviruses with calendar applicat...

  13. Development of a lateral flow test to detect metabolic resistance in Bemisia tabaci mediated by CYP6CM1, a cytochrome P450 with broad spectrum catalytic efficiency.

    PubMed

    Nauen, Ralf; Wölfel, Katharina; Lueke, Bettina; Myridakis, Antonis; Tsakireli, Dimitra; Roditakis, Emmanouil; Tsagkarakou, Anastasia; Stephanou, Euripides; Vontas, John

    2015-06-01

    Cotton whitefly, Bemisia tabaci (Genn.) (Homoptera: Aleyrodidae) is a major sucking pest in many agricultural and horticultural cropping systems globally. The frequent use of insecticides of different mode of action classes resulted in populations resisting treatments used to keep numbers under economic damage thresholds. Recently it was shown that resistance to neonicotinoids such as imidacloprid is linked to the over-expression of CYP6CM1, a cytochrome P450 monooxygenase detoxifying imidacloprid and other neonicotinoid insecticides when recombinantly expressed in insect cells. However over-expression of CYP6CM1 is also known to confer cross-resistance to pymetrozine, an insecticide not belonging to the chemical class of neonicotinoids. In addition we were able to demonstrate by LC-MS/MS analysis the metabolisation of pyriproxyfen by recombinantly expressed CYP6CM1. Based on our results CYP6CM1 is one of the most versatile detoxification enzymes yet identified in a pest of agricultural importance, as it detoxifies a diverse range of chemical classes used to control whiteflies. Therefore we developed a field-diagnostic antibody-based lateral flow assay which detects CYP6CM1 protein at levels providing resistance to neonicotinoids and other insecticides. The ELISA based test kit can be used as a diagnostic tool to support resistance management strategies based on the alternation of different modes of action of insecticides. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. Evidence For Rapid Spatiotemporal Changes in Genetic Structure of an Alien Whitefly During Initial Invasion

    PubMed Central

    Chu, Dong; Guo, Dong; Tao, Yunli; Jiang, Defeng; Li, Jie; Zhang, Youjun

    2014-01-01

    The sweetpotato whitefly Bemisia tabaci Q species is a recent invader and important pest of agricultural crops in China. This research tested the hypothesis that the Q populations that establish in agricultural fields in northern China each year are derived from multiple secondary introductions and/or local populations that overwinter in greenhouses (the pest cannot survive winters in the field in northern China). Here, we report the evidence that the Q populations in agricultural fields mainly derive from multiple secondary introductions. In addition, the common use of greenhouses during the winter in certain locations in northern China helps increase the genetic diversity and the genetic structure of the pest. The genetic structure information generated from this long-term and large-scale field analysis increases our understanding of B. tabaci Q as an invasive pest and has important implications for B. tabaci Q management. PMID:24637851

  15. Assessing the effects of cultivating genetically modified glyphosate-tolerant varieties of soybeans (Glycine max (L.) Merr.) on populations of field arthropods.

    PubMed

    Imura, Osamu; Shi, Kun; Iimura, Keiji; Takamizo, Tadashi

    2010-01-01

    We assessed the effects of cultivating two genetically modified (GM) glyphosate-tolerant soybean varieties (Glycine max (L.) Merr.) derived from Event 40-3-2 and a Japanese conventional variety on arthropods under field conditions, with weed control using glyphosate and conventional weed control for two years. Plant height and dry weight of the conventional variety were significantly larger than those of the GM varieties, but the GM varieties bore more pods than the conventional variety. We found arthropods of nine taxonomic orders (Araneae, Acari, Thysanoptera, Homoptera, Heteroptera, Coleoptera, Diptera, Lepidoptera, and Hymenoptera) on the plants. The arthropod incidence (number per plant unit weight pooled for each taxonomic order) on the soybean stems and leaves generally did not differ significantly between the GM and conventional varieties. However, the incidence of Thysanoptera and total incidence (all orders combined) were greater on the GM variety in the second year. The weed control regimes had no significant influence on the arthropod incidence on the soybean stems and leaves. The number of flower-inhabiting Thysanoptera (the dominant arthropod in the flowers) was not significantly different between the GM and conventional varieties. Asphondylia yushimai (Diptera, Cecidomyiidae) was more numerous on the pods of the GM variety in both years. Neither the soybean variety nor the weed control regime significantly affected the density of soil macro-organisms. However, the glyphosate weed control affected arthropods between the rows of plants by decreasing the abundances of Homoptera, Heteroptera, Coleoptera and Lepidoptera, and diversity of arthropods. © ISBR, EDP Sciences, 2011.

  16. Thrips management program for ornamental plants

    USDA-ARS?s Scientific Manuscript database

    Among the 5,500 (or more) well-described species of thrips (Thysanoptera: Thripidae) worldwide, nearly 1% are known as economically important pests Owing to their polyphagous nature and damage potential to nursery and greenhouse production, thrips inflict millions of dollars loss annually. Thrips ca...

  17. Biology and ecology of the Western Flower Thrips. The making of a pest

    USDA-ARS?s Scientific Manuscript database

    In the past 30 years, the western flower thrips Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) has become one of the most important agricultural pests worldwide. Certain biological attributes of this insect predispose it to be a direct pest across a wide range of crops. In additio...

  18. Remote sensing to detect the movement of wheat curl mites through the spatial spread of virus symptoms, and identification of thrips as predators of wheat curl mites

    NASA Astrophysics Data System (ADS)

    Stilwell, Abby R.

    thrips populations were higher, both in the field and in the greenhouse. Two species of thrips, Thrips tabaci Lindeman and Frankliniella occidentalis (Pergande) were observed to feed directly on WCMs. The collective results from this study identify thrips as a regulating factor for WCM populations.

  19. Management strategies for western flower thrips and the role of insecticides

    USDA-ARS?s Scientific Manuscript database

    Today, the western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) is one of the most significant agricultural pests globally because of the damage it is able to inflict on a wide range of crops. Adults and larvae feed by piercing plant tissues with their needle-shape...

  20. Impacts of pear thrips on a Pennsylvania sugarbush: third year results

    Treesearch

    Thomas E. Kolb; Larry H. McCormick

    1993-01-01

    Pear thrips, Taeniothrips inconsequens (Uzel) (Thysanoptera: Thripidae), were first positively identified as causing damage to sugar maple (Acer saccharum Marsh.) in forest environments in the United States in 1980. Damage in Pennsylvania from this insect has occurred consistently since 1980, with the most extensive impact in 1988...

  1. Spider Communities and Biological Control in Native Habitats Surrounding Greenhouses.

    PubMed

    Cotes, Belén; González, Mónica; Benítez, Emilio; De Mas, Eva; Clemente-Orta, Gemma; Campos, Mercedes; Rodríguez, Estefanía

    2018-03-14

    The promotion of native vegetation as a habitat for natural enemies, which could increase their abundance and fitness, is especially useful in highly simplified settings such as Mediterranean greenhouse landscapes. Spiders as generalist predators may also be involved in intra-guild predation. However, the niche complementarity provided by spiders as a group means that increased spider diversity may facilitate complementary control actions. In this study, the interactions between spiders, the two major horticultural pests, Bemisia tabaci and Frankliniella occidentalis , and their naturally occurring predators and parasitoids were evaluated in a mix of 21 newly planted shrubs selected for habitat management in a highly disturbed horticultural system. The effects of all factors were evaluated using redundancy analysis (RDA) and the generalized additive model (GAM) to assess the statistical significance of abundance of spiders and pests. The GAM showed that the abundance of both pests had a significant effect on hunter spider's abundance, whereas the abundance of B. tabaci , but not F. occidentalis , affected web-weavers' abundance. Ordination analysis showed that spider abundance closely correlated with that of B. tabaci but not with that of F. occidentalis , suggesting that complementarity occurs, and thereby probability of biocontrol, with respect to the targeted pest B. tabaci , although the temporal patterns of the spiders differed from those of F. occidentalis . Conservation strategies involving the establishment of these native plants around greenhouses could be an effective way to reduce pest populations outdoors.

  2. Diversity and Phylogenetic Analyses of Bacterial Symbionts in Three Whitefly Species from Southeast Europe

    PubMed Central

    Skaljac, Marisa; Zanic, Katja; Puizina, Jasna; Lepen Pleic, Ivana; Ghanim, Murad

    2017-01-01

    Bemisia tabaci (Gennadius), Trialeurodes vaporariorum (Westwood), and Siphoninus phillyreae (Haliday) are whitefly species that harm agricultural crops in many regions of the world. These insects live in close association with bacterial symbionts that affect host fitness and adaptation to the environment. In the current study, we surveyed the infection of whitefly populations in Southeast Europe by various bacterial symbionts and performed phylogenetic analyses on the different symbionts detected. Arsenophonus and Hamiltonella were the most prevalent symbionts in all three whitefly species. Rickettsia was found to infect mainly B. tabaci, while Wolbachia mainly infected both B. tabaci and S. phillyreae. Furthermore, Cardinium was rarely found in the investigated whitefly populations, while Fritschea was never found in any of the whitefly species tested. Phylogenetic analyses revealed a diversity of several symbionts (e.g., Hamiltonella, Arsenophonus, Rickettsia), which appeared in several clades. Reproductively isolated B. tabaci and T. vaporariorum shared the same (or highly similar) Hamiltonella and Arsenophonus, while these symbionts were distinctive in S. phillyreae. Interestingly, Arsenophonus from S. phillyreae did not cluster with any of the reported sequences, which could indicate the presence of Arsenophonus, not previously associated with whiteflies. In this study, symbionts (Wolbachia, Rickettsia, and Cardinium) known to infect a wide range of insects each clustered in the same clades independently of the whitefly species. These results indicate horizontal transmission of bacterial symbionts between reproductively isolated whitefly species, a mechanism that can establish new infections that did not previously exist in whiteflies. PMID:29053633

  3. Diversity and Phylogenetic Analyses of Bacterial Symbionts in Three Whitefly Species from Southeast Europe.

    PubMed

    Skaljac, Marisa; Kanakala, Surapathrudu; Zanic, Katja; Puizina, Jasna; Pleic, Ivana Lepen; Ghanim, Murad

    2017-10-20

    Bemisia tabaci (Gennadius), Trialeurodes vaporariorum (Westwood), and Siphoninus phillyreae (Haliday) are whitefly species that harm agricultural crops in many regions of the world. These insects live in close association with bacterial symbionts that affect host fitness and adaptation to the environment. In the current study, we surveyed the infection of whitefly populations in Southeast Europe by various bacterial symbionts and performed phylogenetic analyses on the different symbionts detected. Arsenophonus and Hamiltonella were the most prevalent symbionts in all three whitefly species. Rickettsia was found to infect mainly B. tabaci, while Wolbachia mainly infected both B. tabaci and S. phillyreae. Furthermore, Cardinium was rarely found in the investigated whitefly populations, while Fritschea was never found in any of the whitefly species tested. Phylogenetic analyses revealed a diversity of several symbionts (e.g., Hamiltonella, Arsenophonus, Rickettsia), which appeared in several clades. Reproductively isolated B. tabaci and T. vaporariorum shared the same (or highly similar) Hamiltonella and Arsenophonus, while these symbionts were distinctive in S. phillyreae. Interestingly, Arsenophonus from S. phillyreae did not cluster with any of the reported sequences, which could indicate the presence of Arsenophonus, not previously associated with whiteflies. In this study, symbionts (Wolbachia, Rickettsia, and Cardinium) known to infect a wide range of insects each clustered in the same clades independently of the whitefly species. These results indicate horizontal transmission of bacterial symbionts between reproductively isolated whitefly species, a mechanism that can establish new infections that did not previously exist in whiteflies.

  4. Whiteflies interfere with indirect plant defense against spider mites in Lima bean

    PubMed Central

    Zhang, Peng-Jun; Zheng, Si-Jun; van Loon, Joop J. A.; Boland, Wilhelm; David, Anja; Mumm, Roland; Dicke, Marcel

    2009-01-01

    Plants under herbivore attack are able to initiate indirect defense by synthesizing and releasing complex blends of volatiles that attract natural enemies of the herbivore. However, little is known about how plants respond to infestation by multiple herbivores, particularly if these belong to different feeding guilds. Here, we report the interference by a phloem-feeding insect, the whitefly Bemisia tabaci, with indirect plant defenses induced by spider mites (Tetranychus urticae) in Lima bean (Phaseolus lunatus) plants. Additional whitefly infestation of spider-mite infested plants resulted in a reduced attraction of predatory mites (Phytoseiulus persimilis) compared to attraction to plants infested by spider mites only. This interference is shown to result from the reduction in (E)-β-ocimene emission from plants infested by both spider mites and whiteflies. When using exogenous salicylic acid (SA) application to mimic B. tabaci infestation, we observed similar results in behavioral and chemical analyses. Phytohormone and gene-expression analyses revealed that B. tabaci infestation, as well as SA application, inhibited spider mite-induced jasmonic acid (JA) production and reduced the expression of two JA-regulated genes, one of which encodes for the P. lunatus enzyme β-ocimene synthase that catalyzes the synthesis of (E)-β-ocimene. Remarkably, B. tabaci infestation concurrently inhibited SA production induced by spider mites. We therefore conclude that in dual-infested Lima bean plants the suppression of the JA signaling pathway by whitefly feeding is not due to enhanced SA levels. PMID:19965373

  5. [Effects of Pseudomonas syringae pv. tabaci infection on tobacco photosynthetic apparatus under light or dark conditions.

    PubMed

    Cheng, Dan Dan; Sun, Jian Ping; Chai, Yuan; Zhu, Yi Yong; Zhao, Min; Sun, Guang Yu; Sun, Xing Bin

    2016-08-01

    Pseudomonas syringae pv. tabaci (Pst) is a hemi-biotrophic bacterial pathogen that causes the formation of brown spots named wildfire disease. Pst has received considerable attention in recent years. However, most of the studies focused on the tolerance and defense mechanisms of the host and non-host plants against Pst infection and a toxin originally described as being from Pst named tabtoxin, little information is available on the photosynthetic performance of tobacco leaves after Pst infection. Exploring the effects of Pst on the photosystem Ⅱ (PSⅡ) will not only help in clarifying tobacco-Pst interaction mechanisms, but also deepen the understanding of bacterial pathogen disease from a physiological perspective. By analyzing chlorophyll a fluorescence transient, performing western blot of thylakoid membrane and measuring the content of reactive oxygen species (ROS) and total chlorophyll, the effects of Pst on PS2 in tobacco were studied under light (200 μmol·m -2 ·s -1 ) or dark conditions. The results showed that chlorophyll content significantly decreased and significant chlorosis of the infiltrated zone was observed compared to the untreated ones, and tobacco leaves exhibited a visible and overt wildfire symptom at 3 days post Pst infection (dpi) under light and dark conditions. The H 2 O 2 content increased at 3 dpi compared to untreated ones in tobacco leaves under light and dark conditions, and was much higher under light than dark condition. Besides, markedly increase of the normalized relative variable fluorescence at the K step (W K ) and the relative variable fluorescence at the J step (V J ), significant decrease of maximal quantum yield of PS2 (F v /F m ) and density of Q A - reducing PS2 reaction centers per cross section (RC/CSm) were observed in tobacco leaves after Pst infection at 3 dpi under light and dark conditions. Moreover, inhibition of the K and J steps was more pronounced in the dark, as indicated by the greater increase of W K

  6. Feeding, flight and dispersal in thrips

    Treesearch

    1991-01-01

    The aim of this paper is to amplify some of the general points made in my introductory paper on the order Thysanoptera (Lewis 1990, this proceedings), with particular reference to feeding, flight and dispersal. These aspects of thrips behaviour are clearly of great relevance to the spread and effects of infestations of Taeniothrips inconsequens in...

  7. Improved Sweetpotato Whitefly and Potato Psyllid Control in Tomato by Combining the Mirid Dicyphus hesperus (Heteroptera: Miridae) With Specialist Parasitic Wasps.

    PubMed

    Calvo, F J; Torres-Ruiz, A; Velázquez-González, J; Rodríguez-Leyva, E; Lomeli-Flores, J R

    2018-04-02

    Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) and Bactericera cockerelli Sulcer (Hemiptera: Psyllidae) are important pests in tomato, and the mirid Dicyphus hesperus Knight (Heteroptera: Miridae) has been shown as an effective predator of both pests. Although the predator was able to suppress populations of both pests, the remaining levels could still exceed tolerable levels. Thus, we here hypothesized whether the combination of D. hesperus with the specialist parasitoids Eretmocerus eremicus Rose y Zolnerowich (Hymenoptera: Aphelinidae) (whitefly) and Tamarixia triozae (Burks) (Hymenoptera: Eulophidae) (psyllid) would result in better pest control on a greenhouse scale. For that, we conducted a trial in which we compared the results against B. tabaci and B. cockerelli in greenhouses treated with D. hesperus alone or the predator in combination with the specialist parasitoids. The results showed that the predator was able to establish and suppress B. tabaci and B. cockerelli in tomato, but the addition of the specialist parasitoids resulted in better and more cost-effective pest control. Implementation of this method would therefore increase the robustness and reliability of biocontrol-based integrated pest management programmes for tomato crops, over methods based exclusively on D. hesperus release.

  8. The Contrasting Effects of Elevated CO2 on TYLCV Infection of Tomato Genotypes with and without the Resistance Gene, Mi-1.2.

    PubMed

    Guo, Huijuan; Huang, Lichao; Sun, Yucheng; Guo, Honggang; Ge, Feng

    2016-01-01

    Elevated atmospheric CO 2 typically enhances photosynthesis of C3 plants and alters primary and secondary metabolites in plant tissue. By modifying the defensive signaling pathways in host plants, elevated CO 2 could potentially affect the interactions between plants, viruses, and insects that vector viruses. R gene-mediated resistance in plants represents an efficient and highly specific defense against pathogens and herbivorous insects. The current study determined the effect of elevated CO 2 on tomato plants with and without the nematode resistance gene Mi-1.2 , which also confers resistance to some sap-sucking insects including whitefly, Bemisia tabaci . Furthermore, the subsequent effects of elevated CO 2 on the performance of the vector whiteflies and the severity of Tomato yellow leaf curl virus (TYLCV) were also determined. The results showed that elevated CO 2 increased the biomass, plant height, and photosynthetic rate of both the Moneymaker and the Mi-1.2 genotype. Elevated CO 2 decreased TYLCV disease incidence and severity for Moneymaker plants but had the opposite effect on Mi-1.2 plants whether the plants were agroinoculated or inoculated via B. tabaci feeding. Elevated CO 2 increased the salicylic acid (SA)-dependent signaling pathway on Moneymaker plants but decreased the SA-signaling pathway on Mi-1.2 plants when infected by TYLCV. Elevated CO 2 did not significantly affect B. tabaci fitness or the ability of viruliferous B. tabaci to transmit virus regardless of plant genotype. The results indicate that elevated CO 2 increases the resistance of Moneymaker plants but decreases the resistance of Mi-1.2 plants against TYLCV, whether the plants are agroinoculated or inoculated by the vector. Our results suggest that plant genotypes containing the R gene Mi-1.2 will be more vulnerable to TYLCV and perhaps to other plant viruses under elevated CO 2 conditions.

  9. A male-predominant cuticular hydrocarbon, 7-methyltricosane, is used as a contact pheromone in the western flower thrips Frankliniella occidentalis.

    PubMed

    Olaniran, Oladele A; Sudhakar, Akella V S; Drijfhout, Falko P; Dublon, Ian A N; Hall, David R; Hamilton, James G C; Kirk, William D J

    2013-04-01

    In a laboratory bioassay, adult female Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) spent more time near filter paper disks that had been exposed to adult males than near unexposed disks; this effect was not observed on disks exposed to adult females. The response could only partly be explained by the known male-produced aggregation pheromone, neryl (S)-2-methylbutanoate, suggesting the presence of an unknown male-produced compound. In gas chromatography/mass spectrometry analyses, 7-methyltricosane was detected on disks exposed to males, but not on disks exposed to females. Extracts of cuticular lipids also showed relatively large amounts of 7-methyltricosane on males, whereas only trace amounts were found on females and none on larvae. Bioassays of synthetic 7-methyltricosane showed that adults responded only after contact. The response to this compound was clearly different from that to n-tricosane or hexane-only controls. Females that contacted 7-methyltricosane on glass beads stayed in the vicinity and frequently raised the abdomen, a behavior that rejects mating attempts by males. Males stayed in the vicinity and wagged the abdomen sideways, a behavior used in fighting between males. This is the first identification of a contact pheromone in the order Thysanoptera.

  10. Novel molecular approach to define pest species status and tritrophic interactions from historical Bemisia specimens.

    PubMed

    Tay, W T; Elfekih, S; Polaszek, A; Court, L N; Evans, G A; Gordon, K H J; De Barro, P J

    2017-03-27

    Museum specimens represent valuable genomic resources for understanding host-endosymbiont/parasitoid evolutionary relationships, resolving species complexes and nomenclatural problems. However, museum collections suffer DNA degradation, making them challenging for molecular-based studies. Here, the mitogenomes of a single 1912 Sri Lankan Bemisia emiliae cotype puparium, and of a 1942 Japanese Bemisia puparium are characterised using a Next-Generation Sequencing approach. Whiteflies are small sap-sucking insects including B. tabaci pest species complex. Bemisia emiliae's draft mitogenome showed a high degree of homology with published B. tabaci mitogenomes, and exhibited 98-100% partial mitochondrial DNA Cytochrome Oxidase I (mtCOI) gene identity with the B. tabaci species known as Asia II-7. The partial mtCOI gene of the Japanese specimen shared 99% sequence identity with the Bemisia 'JpL' genetic group. Metagenomic analysis identified bacterial sequences in both Bemisia specimens, while hymenopteran sequences were also identified in the Japanese Bemisia puparium, including complete mtCOI and rRNA genes, and various partial mtDNA genes. At 88-90% mtCOI sequence identity to Aphelinidae wasps, we concluded that the 1942 Bemisia nymph was parasitized by an Eretmocerus parasitoid wasp. Our approach enables the characterisation of genomes and associated metagenomic communities of museum specimens using 1.5 ng gDNA, and to infer historical tritrophic relationships in Bemisia whiteflies.

  11. Tomato Infection by Whitefly-Transmitted Circulative and Non-Circulative Viruses Induce Contrasting Changes in Plant Volatiles and Vector Behaviour

    PubMed Central

    Fereres, Alberto; Peñaflor, Maria Fernanda G. V.; Favaro, Carla F.; Azevedo, Kamila E. X.; Landi, Carolina H.; Maluta, Nathalie K. P.; Bento, José Mauricio S.; Lopes, Joao R.S.

    2016-01-01

    Virus infection frequently modifies plant phenotypes, leading to changes in behaviour and performance of their insect vectors in a way that transmission is enhanced, although this may not always be the case. Here, we investigated Bemisia tabaci response to tomato plants infected by Tomato chlorosis virus (ToCV), a non-circulative-transmitted crinivirus, and Tomato severe rugose virus (ToSRV), a circulative-transmitted begomovirus. Moreover, we examined the role of visual and olfactory cues in host plant selection by both viruliferous and non-viruliferous B. tabaci. Visual cues alone were assessed as targets for whitefly landing by placing leaves underneath a Plexiglas plate. A dual-choice arena was used to assess whitefly response to virus-infected and mock-inoculated tomato leaves under light and dark conditions. Thereafter, we tested the whitefly response to volatiles using an active air-flow Y-tube olfactometer, and chemically characterized the blends using gas chromatography coupled to mass spectrometry. Visual stimuli tests showed that whiteflies, irrespective of their infectious status, always preferred to land on virus-infected rather than on mock-inoculated leaves. Furthermore, whiteflies had no preference for either virus-infected or mock-inoculated leaves under dark conditions, but preferred virus-infected leaves in the presence of light. ToSRV-infection promoted a sharp decline in the concentration of some tomato volatiles, while an increase in the emission of some terpenes after ToCV infection was found. ToSRV-viruliferous whiteflies preferred volatiles emitted from mock-inoculated plants, a conducive behaviour to enhance virus spread, while volatiles from ToCV-infected plants were avoided by non-viruliferous whiteflies, a behaviour that is likely detrimental to the secondary spread of the virus. In conclusion, the circulative persistent begomovirus, ToSRV, seems to have evolved together with its vector B. tabaci to optimise its own spread. However

  12. Overlapping Yet Response-Specific Transcriptome Alterations Characterize the Nature of Tobacco-Pseudomonas syringae Interactions.

    PubMed

    Bozsó, Zoltán; Ott, Péter G; Kámán-Tóth, Evelin; Bognár, Gábor F; Pogány, Miklós; Szatmári, Ágnes

    2016-01-01

    In this study transcriptomic alterations of bacterially induced pattern triggered immunity (PTI) were compared with other types of tobacco-Pseudomonas interactions. In addition, using pharmacological agents we blocked some signal transduction pathways (Ca(2+) influx, kinases, phospholipases, proteasomic protein degradation) to find out how they contribute to gene expression during PTI. PTI is the first defense response of plant cells to microbes, elicited by their widely conserved molecular patterns. Tobacco is an important model of Solanaceae to study resistance responses, including defense mechanisms against bacteria. In spite of these facts the transcription regulation of tobacco genes during different types of plant bacterial interactions is not well-described. In this paper we compared the tobacco transcriptomic alterations in microarray experiments induced by (i) PTI inducer Pseudomonas syringae pv. syringae type III secretion mutant (hrcC) at earlier (6 h post inoculation) and later (48 hpi) stages of defense, (ii) wild type P. syringae (6 hpi) that causes effector triggered immunity (ETI) and cell death (HR), and (iii) disease-causing P. syringae pv. tabaci (6 hpi). Among the different treatments the highest overlap was between the PTI and ETI at 6 hpi, however, there were groups of genes with specifically altered activity for either type of defenses. Instead of quantitative effects of the virulent P. tabaci on PTI-related genes it influenced transcription qualitatively and blocked the expression changes of a special set of genes including ones involved in signal transduction and transcription regulation. P. tabaci specifically activated or repressed other groups of genes seemingly not related to either PTI or ETI. Kinase and phospholipase A inhibitors had highest impacts on the PTI response and effects of these signal inhibitors on transcription greatly overlapped. Remarkable interactions of phospholipase C-related pathways with the proteasomal system were

  13. Tomato Infection by Whitefly-Transmitted Circulative and Non-Circulative Viruses Induce Contrasting Changes in Plant Volatiles and Vector Behaviour.

    PubMed

    Fereres, Alberto; Peñaflor, Maria Fernanda G V; Favaro, Carla F; Azevedo, Kamila E X; Landi, Carolina H; Maluta, Nathalie K P; Bento, José Mauricio S; Lopes, Joao R S

    2016-08-11

    Virus infection frequently modifies plant phenotypes, leading to changes in behaviour and performance of their insect vectors in a way that transmission is enhanced, although this may not always be the case. Here, we investigated Bemisia tabaci response to tomato plants infected by Tomato chlorosis virus (ToCV), a non-circulative-transmitted crinivirus, and Tomato severe rugose virus (ToSRV), a circulative-transmitted begomovirus. Moreover, we examined the role of visual and olfactory cues in host plant selection by both viruliferous and non-viruliferous B. tabaci. Visual cues alone were assessed as targets for whitefly landing by placing leaves underneath a Plexiglas plate. A dual-choice arena was used to assess whitefly response to virus-infected and mock-inoculated tomato leaves under light and dark conditions. Thereafter, we tested the whitefly response to volatiles using an active air-flow Y-tube olfactometer, and chemically characterized the blends using gas chromatography coupled to mass spectrometry. Visual stimuli tests showed that whiteflies, irrespective of their infectious status, always preferred to land on virus-infected rather than on mock-inoculated leaves. Furthermore, whiteflies had no preference for either virus-infected or mock-inoculated leaves under dark conditions, but preferred virus-infected leaves in the presence of light. ToSRV-infection promoted a sharp decline in the concentration of some tomato volatiles, while an increase in the emission of some terpenes after ToCV infection was found. ToSRV-viruliferous whiteflies preferred volatiles emitted from mock-inoculated plants, a conducive behaviour to enhance virus spread, while volatiles from ToCV-infected plants were avoided by non-viruliferous whiteflies, a behaviour that is likely detrimental to the secondary spread of the virus. In conclusion, the circulative persistent begomovirus, ToSRV, seems to have evolved together with its vector B. tabaci to optimise its own spread. However

  14. Geraniol encapsulated in chitosan/gum arabic nanoparticles: a promising system for pest management in sustainable agriculture.

    PubMed

    de Oliveira, Jhones Luiz; Campos, Estefania Vangelie Ramos; Pereira, Anderson E S; Nunes, Lucas E S; da Silva, Camila C L; Pasquoto, Tatiane; Lima, Renata; Smaniotto, Giovani; Polanczyk, Ricardo Antonio; Fraceto, Leonardo F

    2018-05-07

    The nanoencapsulation of botanical compounds (such as geraniol) is an important strategy that can be used to increase the stability and efficiency of these substances in integrated pest management. In this study, chitosan/gum arabic nanoparticles containing geraniol were prepared and characterized. In addition, evaluation was made of the biological activity of geraniol encapsulated in chitosan/gum arabic nanoparticles towards whitefly (Bemisia tabaci). The optimized formulation showed a high encapsulation efficiency (>90%) and remained stable for about 120 days. The formulation protected the geraniol against degradation by UV radiation, and the in vitro release was according to a diffusion mechanism that was influenced by temperature. An attraction effect was observed for Bemisia tabaci, indicating the potential of this type of system for use in pest management, especially in trap devices.

  15. Persistent, circulative transmission of begomoviruses by whitefly vectors.

    PubMed

    Rosen, Ran; Kanakala, Surapathrudu; Kliot, Adi; Cathrin Pakkianathan, Britto; Farich, Basheer Abu; Santana-Magal, Nadine; Elimelech, Meytar; Kontsedalov, Svetlana; Lebedev, Galina; Cilia, Michelle; Ghanim, Murad

    2015-12-01

    Begomoviruses comprise an emerging and economically important group of plant viruses exclusively transmitted by the sweetpotato whitefly Bemisia tabaci in many regions of the world. The past twenty years have witnessed significant progress in studying the molecular interactions between members of this virus group and B. tabaci. Mechanisms and proteins encoded by the insect vector and its bacterial symbionts, which have been shown to be important for virus transmission, have been identified and thoroughly studied. Despite the economic importance of this group of viruses and their impact on the global agriculture, progress in investigating the virus-vector interactions is moving slowly when compared with similar virus-vector systems in plants and animals. Major advances in this field and future perspectives will be discussed in this review. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Effects of selected defoliants in combination with insecticides on sweetpotato whitefly (Hemiptera: Aleyrodidae) and its parasitoids in cotton

    USDA-ARS?s Scientific Manuscript database

    Effects of two defoliants, Def (S, S, Stributylphosphorotrithioate) and Dropp (thidiazuron) alone and in combination with two commonly used insecticides, a pyrethroid, Karate (lambda-cyhalothrin) and an organophosphate, Guthion (azinphosmethyl) on sweetpotato whitefly, Bemisia tabaci Gennadius Bioty...

  17. RNA viral metagenome of whiteflies leads to the discovery and characterization of a whitefly-transmitted carlavirus in North America.

    PubMed

    Rosario, Karyna; Capobianco, Heather; Ng, Terry Fei Fan; Breitbart, Mya; Polston, Jane E

    2014-01-01

    Whiteflies from the Bemisia tabaci species complex have the ability to transmit a large number of plant viruses and are some of the most detrimental pests in agriculture. Although whiteflies are known to transmit both DNA and RNA viruses, most of the diversity has been recorded for the former, specifically for the Begomovirus genus. This study investigated the total diversity of DNA and RNA viruses found in whiteflies collected from a single site in Florida to evaluate if there are additional, previously undetected viral types within the B. tabaci vector. Metagenomic analysis of viral DNA extracted from the whiteflies only resulted in the detection of begomoviruses. In contrast, whiteflies contained sequences similar to RNA viruses from divergent groups, with a diversity that extends beyond currently described viruses. The metagenomic analysis of whiteflies also led to the first report of a whitefly-transmitted RNA virus similar to Cowpea mild mottle virus (CpMMV Florida) (genus Carlavirus) in North America. Further investigation resulted in the detection of CpMMV Florida in native and cultivated plants growing near the original field site of whitefly collection and determination of its experimental host range. Analysis of complete CpMMV Florida genomes recovered from whiteflies and plants suggests that the current classification criteria for carlaviruses need to be reevaluated. Overall, metagenomic analysis supports that DNA plant viruses carried by B. tabaci are dominated by begomoviruses, whereas significantly less is known about RNA viruses present in this damaging insect vector.

  18. Inundative Field Releases and Evaluation of Three Predators for Bemisia tabasi (Hemiptera: Aleyrodidae) Management in Three Vegetable Crops

    USDA-ARS?s Scientific Manuscript database

    The sweetpotato whitefly, Bemisia tabaci (Gennadius), is a global pest on numerous crops, including vegetables. Weekly inundative releases of a coccinellid predator (Coccinella undecimpunctata L.), a mirid predator [Macrophillus caliginosus (Wagner)] and a neuropteran predator [Chrysoperla carnea S...

  19. Susceptibility of ornamental pepper banker plant candidates to common greenhouse pests

    USDA-ARS?s Scientific Manuscript database

    Susceptibility of four potential ornamental pepper banker plant candidates [Black Pearl (BP), Explosive Ember (EE), Masquerade (MA), Red Missile (RM), and a commercial pepper cultivar Blitz (BL)] were evaluated against three common greenhouse pests - Bemisia tabaci, Polyphagotarsonemus latus and Fra...

  20. Comparative toxicities of newer and conventional insecticides against four generalist predator species

    USDA-ARS?s Scientific Manuscript database

    Generalist insect predators play an essential role at regulating populations of Bemisia tabaci and other pests in agricultural systems, but face depredations due to insecticide applications. Evaluation of insecticide compatibility with specific predator species can provide a basis for making treatme...

  1. Potential sources of whitefly (Hemiptera: Aleyrodidae) resistance in desert watermelon (Citrullus colocynthis) germplasm

    USDA-ARS?s Scientific Manuscript database

    Selection for host plant resistance and incorporation of natural resistance into cultivars is a fundamental strategy to control insects and diseases in an environmentally-sensitive manner, and may help reduce reliance on synthetic pesticides. The sweetpotato whitefly, Bemisia tabaci (Gennadius), is...

  2. Innate responses to putative ancestral hosts: is the attraction of Western flower thrips to pine pollen a result of relict olfactory receptors?

    PubMed

    Abdullah, Zayed S; Ficken, Katherine J; Greenfield, Bethany P J; Butt, Tariq M

    2014-06-01

    Pollinophagy is widely documented in the order Thysanoptera, with representative individuals from six of the nine divergent families known to feed on pollen. Various pollens of the genus Pinus increase the development time, fecundity, longevity, and settling preference of Western Flower Thrips (WFT), Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). Certain species of flower thrips discriminate among pollen types, but no studies have elucidated the olfactory cues that play a role in their pollen preferences. In this study, the volatile organic compounds emitted by pollens of the genus Pinus were elucidated. Various chemicals from pollen headspace elicited electrophysiological responses from WFT antennae. The compound (S)-(-)-verbenone, identified in pollen headspace, attracted WFT in a 4-arm olfactometer. This compound has potential for use in integrated pest management programs against the pest. We present the hypothesis that this polyphagous insect may have retained ancestral 'relict' olfactory receptors through the course of evolution, to explain this attraction to pine pollen. This attraction has allowed the insect to find and exploit an unusual nutrient source that significantly increases its fitness. The study demonstrates how fossil record analysis and subsequent evolutionary knowledge can aid in explaining possibilities as to why some insects sense and respond to chemicals that would otherwise seem peculiar to their ecology, allowing insight into the evolutionary forces that may shape insect olfactory systems over time.

  3. Transcriptomics-guided development of RNA interference strategies to manage whiteflies: a globally distributed vector of crop viruses

    USDA-ARS?s Scientific Manuscript database

    Over 300 viruses are transmitted by the whitefly, Bemisia tabaci, with 90% of them belonging to the genus, Begomovirus. Begomoviruses are exclusively transmitted by whiteflies to a range of agriculture crops, resulting in billions of dollars lost annually, while jeopardizing food security worldwide....

  4. Whitefly transmission of Sweet potato leaf curl virus in sweetpotato germplasm

    USDA-ARS?s Scientific Manuscript database

    Sweetpotato, Ipomoea batatas (L.) Lam., is among an extensive number of plant species attacked by Bemisia tabaci (Gennadius). Because this important world food crop is vegetatively propagated, it can conveniently accumulate infections by several viruses. Sweet potato leaf curl virus (SPLCV) (ssDNA...

  5. Persistent, circulative transmission of begomoviruses by whitefly vectors

    USDA-ARS?s Scientific Manuscript database

    Begomoviruses comprise an emerging and economically important group of plant viruses exclusively transmitted by the sweetpotato whitefly Bemisia tabaci in many regions of the world. The past twenty years have witnessed significant progress in studying the molecular interactions between members of th...

  6. Precision phenotyping of epicuticular waxes associated with insect resistance

    USDA-ARS?s Scientific Manuscript database

    Accurate phenotyping is imperative for linkage mapping and association genetics. Amounts and types of epicuticular waxes on the leaf surface are important for plant-insect interactions. In onion, specific wax profiles are associated with resistance to the insect pest Thrips tabaci. Epicuticular wax ...

  7. Partial leaf chemical profiles of a desert watermelon species (Citrullus colocynthis) and heirloom watermelon cultivars (Citrullus lanatus var. lanatus)

    USDA-ARS?s Scientific Manuscript database

    Whiteflies [Bemisia tabaci (Gennadius)] and aphids [Aphis gossypii Glover and Myzus persicae (Sulzer)] are serious threats to watermelon by direct feeding and by transmitting viruses of important virus diseases. The desert watermelon Citrullus colocynthis (L.) has been shown to exhibit resistance t...

  8. Stage-Related Defense Response Induction in Tomato Plants by Nesidiocoris tenuis

    PubMed Central

    Naselli, Mario; Urbaneja, Alberto; Siscaro, Gaetano; Jaques, Josep A.; Zappalà, Lucia; Flors, Víctor; Pérez-Hedo, Meritxell

    2016-01-01

    The beneficial effects of direct predation by zoophytophagous biological control agents (BCAs), such as the mirid bug Nesidiocoris tenuis, are well-known. However, the benefits of zoophytophagous BCAs’ relation with host plants, via induction of plant defensive responses, have not been investigated until recently. To date, only the females of certain zoophytophagous BCAs have been demonstrated to induce defensive plant responses in tomato plants. The aim of this work was to determine whether nymphs, adult females, and adult males of N. tenuis are able to induce defense responses in tomato plants. Compared to undamaged tomato plants (i.e., not exposed to the mirid), plants on which young or mature nymphs, or adult males or females of N. tenuis fed and developed were less attractive to the whitefly Bemisia tabaci, but were more attractive to the parasitoid Encarsia formosa. Female-exposed plants were more repellent to B. tabaci and more attractive to E. formosa than were male-exposed plants. When comparing young- and mature-nymph-exposed plants, the same level of repellence was obtained for B. tabaci, but mature-nymph-exposed plants were more attractive to E. formosa. The repellent effect is attributed to the signaling pathway of abscisic acid, which is upregulated in N. tenuis-exposed plants, whereas the parasitoid attraction was attributed to the activation of the jasmonic acid signaling pathway. Our results demonstrate that all motile stages of N. tenuis can trigger defensive responses in tomato plants, although these responses may be slightly different depending on the stage considered. PMID:27472328

  9. Modeling trophic dependencies and exchanges among insects' bacterial symbionts in a host-simulated environment.

    PubMed

    Opatovsky, Itai; Santos-Garcia, Diego; Ruan, Zhepu; Lahav, Tamar; Ofaim, Shany; Mouton, Laurence; Barbe, Valérie; Jiang, Jiandong; Zchori-Fein, Einat; Freilich, Shiri

    2018-05-25

    Individual organisms are linked to their communities and ecosystems via metabolic activities. Metabolic exchanges and co-dependencies have long been suggested to have a pivotal role in determining community structure. In phloem-feeding insects such metabolic interactions with bacteria enable complementation of their deprived nutrition. The phloem-feeding whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) harbors an obligatory symbiotic bacterium, as well as varying combinations of facultative symbionts. This well-defined bacterial community in B. tabaci serves here as a case study for a comprehensive and systematic survey of metabolic interactions within the bacterial community and their associations with documented occurrences of bacterial combinations. We first reconstructed the metabolic networks of five common B. tabaci symbionts genera (Portiera, Rickettsia, Hamiltonella, Cardinium and Wolbachia), and then used network analysis approaches to predict: (1) species-specific metabolic capacities in a simulated bacteriocyte-like environment; (2) metabolic capacities of the corresponding species' combinations, and (3) dependencies of each species on different media components. The predictions for metabolic capacities of the symbionts in the host environment were in general agreement with previously reported genome analyses, each focused on the single-species level. The analysis suggests several previously un-reported routes for complementary interactions and estimated the dependency of each symbiont in specific host metabolites. No clear association was detected between metabolic co-dependencies and co-occurrence patterns. The analysis generated predictions for testable hypotheses of metabolic exchanges and co-dependencies in bacterial communities and by crossing them with co-occurrence profiles, contextualized interaction patterns into a wider ecological perspective.

  10. RNAi-mediated mortality of the whitefly through transgenic expression of double-stranded RNA homologous to acetylcholinesterase and ecdysone receptor in tobacco plants

    USDA-ARS?s Scientific Manuscript database

    The whitefly Bemisia tabaci (Genn.) is a pest and vector of plant viruses affecting plants worldwide. Using RNA interference (RNAi) to downregulate whitefly genes by expressing their homologous double stranded RNAs in plants has great potential for management of whiteflies to reduce plant virus dise...

  11. Developing ribonucleic acid interference technology to manage whitefly-transmitted begomoviruses

    USDA-ARS?s Scientific Manuscript database

    Of nearly 300 viruses transmitted by the whitefly (Bemisia tabaci), 90% of them belong to the genus Begomovirus. Begomoviruses are efficiently transmitted by whiteflies to a range of agricultural crops. This results in billions of dollars lost annually, while jeopardizing food security worldwide. Se...

  12. Isaria poprawskii sp. nov. (Hypocreales: Cordycipitacae), a new entomopathogenic fungus from Texas affecting sweet potato whitefly

    USDA-ARS?s Scientific Manuscript database

    Isaria poprawskii is described as a new entomopathogenic species similar to Isaria javanica (=Paecilomyces javanicus). It was discovered ont he sweet potato whitefly, Bemisia tabaci biotype B in the Lower Rio Grande Valley of Texas (LRGV), USA. Morphological and DNA examinations indicated the dist...

  13. Metabolic coevolution in the bacterial symbiosis of whiteflies and related plant sap-feeding insects

    USDA-ARS?s Scientific Manuscript database

    In animals dependent on intracellular bacteria with very small genomes, the host cell is adapted to support the function of its bacterial symbionts, but the molecular basis of these adaptations is poorly understood. We investigated the metabolic coevolution between the whitefly Bemisia tabaci and th...

  14. Companion and refuge plants to control insect pests

    USDA-ARS?s Scientific Manuscript database

    Introduction: The sweetpotato whitefly, Bemisia tabaci and aphids are major pests of crops in the southeast USA. An environmentally-friendly management strategy is “push-pull” technology which combines the use of repellent (“push”) and trap crops (“pull”) for insect pest control. The repellent crop,...

  15. Variation for epicuticular waxes and thrips resistance in onion

    USDA-ARS?s Scientific Manuscript database

    Onion thrips (Thrips tabaci) and thrips-vectored Iris Yellow Spot Virus (IYSV) routinely cause significant losses to the bulb and seed crops of onion. Both pests have become more problematic as global temperatures rise. Natural variation exists in onion for amounts and types of epicuticular waxes on...

  16. Effects of a foliar neem formulation on colonization and mortality of whiteflies (Hemiptera: Aleyrodidae) on collard plants

    USDA-ARS?s Scientific Manuscript database

    A study was conducted to determine the effects of foliar sprays of a selected neem (Azadirachta indica A. Juss) product (GOS Neem 7-Way) on colonization and development by the Middle-East Asia Minor-1 (= B-biotype sweetpotato whitefly) Bemisia tabaci (Gennadius) on collard (Brassica oleracea variety...

  17. Agroecological niches and thrips (Thysanoptera: Thripidae) dynamics

    Treesearch

    Michael E. Irwin

    1991-01-01

    In 1975, Illinois experienced an exceptionally mild winter, followed by a warm spring. This sequence of climatic events resulted in a massive outbreak of the soybean thrips, Sericothrips variabilis (Beach), along with large numbers of the flower thrips, Frankliniella tritici (Fitch). The outbreak covered an area of over 600...

  18. Recessive resistance to Cucurbit yellow stunting disorder virus in melon

    USDA-ARS?s Scientific Manuscript database

    Cucurbit yellow stunting disorder virus (CYSDV) reduces melon (Cucumis melo L.) fruit quality and yield in many parts of the world. CYSDV and its vector, sweetpotato whitefly (MEAM1 cryptic species of Bemisia tabaci; SPWF) are a devastating combination in the Sonoran Desert areas of California and A...

  19. Papaya is not a host for Tomato Yellow Leaf Curl Virus

    USDA-ARS?s Scientific Manuscript database

    The economic value of tomato production is threatened by tomato yellow leaf-curl virus TYLCV and its vector, the silverleaf whitefly Bemisia tabaci biotype B (Gennadius) (Hemiptera: Aleyrodidae). Use of papaya Carica papaya L. as a banker plant for a whitefly parasitoid shows promise as a whitefly m...

  20. Breeding for cotton leaf curl disease (CLCuD) resistance

    USDA-ARS?s Scientific Manuscript database

    Cotton leaf curl disease (CLCuD) is caused by a whitefly (Bemisia tabaci) transmitted geminivirus. It is a major disease of cotton in Africa and South Asia, and has spread to other countries through ornamental plants. It can potentially devastate U.S. cotton where commercial varieties have no resi...

  1. First report of an ipomovirus infecting cucurbits in the Imperial Valley of California

    USDA-ARS?s Scientific Manuscript database

    In the fall of 2014, pumpkin plants grown at the University of California Desert Research Extension Center (DREC) in Holtville, CA showed severe stunting, leaf yellowing, crumpling, and epinasty. These plants were also infested with high populations of B. tabaci. RT-PCR and PCR tests performed on le...

  2. Tracking disease and insect pests using Smartphone technology: a new approach for regional (and local) pest management

    USDA-ARS?s Scientific Manuscript database

    Tomato yellow leaf curl virus (TYLCV) is vectored by the silverleaf whitefly (Bemisia tabaci biotype B) and was first detected in south Florida in 1997. The virus has spread widely in Florida and is responsible for millions of dollars of lost production. Anlaysis of data from a comprehensive, multi-...

  3. Epidemiology of Cucurbit yellow stunting disorder virus in the US Southwest and development of virus resistant melon

    USDA-ARS?s Scientific Manuscript database

    Cucurbit yellow stunting disorder virus (CYSDV), emerged in the Southwest USA in 2006, where it is transmitted by the MEAM1 cryptic species of Bemisia tabaci. The virus results in late-season infection of spring melon crops with limited economic impact; however, all summer and fall cucurbits become ...

  4. A new and potentially damaging whitefly-transmitted virus of cucurbits was found this fall 2014 in Imperial County, CA

    USDA-ARS?s Scientific Manuscript database

    A new virus that appears to be related to but distinct from Squash vein yellowing virus (SqVYV), a Bemisia tabaci-transmitted ipomovirus (family Potyviridae) that occurs in Florida was found in fall 2014 in Imperial County, CA infecting pumpkin and melon plants and exhibiting symptoms of stunting an...

  5. Maize Chlorotic Mottle Virus Induces Changes in Host Plant Volatiles that Attract Vector Thrips Species.

    PubMed

    Mwando, Nelson L; Tamiru, Amanuel; Nyasani, Johnson O; Obonyo, Meshack A O; Caulfield, John C; Bruce, Toby J A; Subramanian, Sevgan

    2018-06-02

    Maize lethal necrosis is one of the most devastating diseases of maize causing yield losses reaching up to 90% in sub-Saharan Africa. The disease is caused by a combination of maize chlorotic mottle virus (MCMV) and any one of cereal viruses in the Potyviridae group such as sugarcane mosaic virus. MCMV has been reported to be transmitted mainly by maize thrips (Frankliniella williamsi) and onion thrips (Thrips tabaci). To better understand the role of thrips vectors in the epidemiology of the disease, we investigated behavioral responses of F. williamsi and T. tabaci, to volatiles collected from maize seedlings infected with MCMV in a four-arm olfactometer bioassay. Volatile profiles from MCMV-infected and healthy maize plants were compared by gas chromatography (GC) and GC coupled mass spectrometry analyses. In the bioassays, both sexes of F. williamsi and male T. tabaci were significantly attracted to volatiles from maize plants infected with MCMV compared to healthy plants and solvent controls. Moreover, volatile analysis revealed strong induction of (E)-4,8-dimethyl-1,3,7-nonatriene, methyl salicylate and (E,E)-4,8,12-trimethyltrideca-1,3,7,11-tetraene in MCMV-infected maize seedlings. Our findings demonstrate MCMV induces changes in volatile profiles of host plants to elicit attraction of thrips vectors. The increased vector contact rates with MCMV-infected host plants could enhance virus transmission if thrips feed on the infected plants and acquire the pathogen prior to dispersal. Uncovering the mechanisms mediating interactions between vectors, host plants and pathogens provides useful insights for understanding the vector ecology and disease epidemiology, which in turn may contribute in designing integrated vector management strategies.

  6. Species Delimitation and Global Biosecurity

    PubMed Central

    Boykin, Laura M.; Armstrong, Karen F.; Kubatko, Laura; De Barro, Paul

    2012-01-01

    Species delimitation directly impacts on global biosecurity. It is a critical element in the decisions made by national governments in regard to the flow of trade and to the biosecurity measures imposed to protect countries from the threat of invasive species. Here we outline a novel approach to species delimitation, “tip to root”, for two highly invasive insect pests, Bemisia tabaci (sweetpotato whitefly) and Lymantria dispar (Asian gypsy moth). Both species are of concern to biosecurity, but illustrate the extremes of phylogenetic resolution that present the most complex delimitation issues for biosecurity; B. tabaci having extremely high intra-specific genetic variability and L. dispar composed of relatively indistinct subspecies. This study tests a series of analytical options to determine their applicability as tools to provide more rigorous species delimitation measures and consequently more defensible species assignments and identification of unknowns for biosecurity. Data from established DNA barcode datasets (COI), which are becoming increasingly considered for adoption in biosecurity, were used here as an example. The analytical approaches included the commonly used Kimura two-parameter (K2P) inter-species distance plus four more stringent measures of taxon distinctiveness, (1) Rosenberg’s reciprocal monophyly, (P(AB)),1 (2) Rodrigo’s (P(randomly distinct)),2 (3) genealogical sorting index, (gsi),3 and (4) General mixed Yule-coalescent (GMYC).4,5 For both insect datasets, a comparative analysis of the methods revealed that the K2P distance method does not capture the same level of species distinctiveness revealed by the other three measures; in B. tabaci there are more distinct groups than previously identified using the K2P distances and for L. dipsar far less variation is apparent within the predefined subspecies. A consensus for the results from P(AB), P(randomly distinct) and gsi offers greater statistical confidence as to where genetic limits

  7. Emergence and epidemiology of Cucurbit yellow stunting disorder virus in the American desert southwest, and development of host plant resistance in melon

    USDA-ARS?s Scientific Manuscript database

    Cucurbit yellow stunting disorder virus (CYSDV), emerged in the Sonoran Desert region of the southwestern USA in 2006 and has become established. The virus is transmitted by the MEAM1 cryptic species of Bemisia tabaci, which has been present in the region since the early 1990s. CYSDV results in lat...

  8. Biochemical analysis of leaf waxes and thrips resistance in onion selections

    USDA-ARS?s Scientific Manuscript database

    Thrips (Thrips tabaci) is a serious insect pest of onion and is a vector for Iris yellow spot virus (IYSV). Lower amounts of epicuticular waxes on onion leaves have been associated with fewer thrips, less feeding damage, and lower incidence of IYSV. In this study, 10 onion selections that showed les...

  9. Plant virus differentially alters the plant's defense response to its closely related vectors.

    PubMed

    Shi, Xiaobin; Pan, Huipeng; Xie, Wen; Wu, Qingjun; Wang, Shaoli; Liu, Yang; Fang, Yong; Chen, Gong; Gao, Xiwu; Zhang, Youjun

    2013-01-01

    The whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae), is one of the most widely distributed agricultural pests. In recent years, B. tabaci Q has invaded China, and Q has displaced B in many areas now. In a number of regions of the world, invasion by B and/or Q has been followed by outbreaks of tomato yellow leaf curl virus (TYLCV). Our previous study showed TYLCV directly and indirectly modified the feeding behavior of B. tabaci in favor of Q rather than B. In this study, we quantified the salicylic acid (SA) titers and relative gene expression of SA in tomato leaves that were infested with viruliferous or non-viruliferous B and Q. We also measured the impacts of exogenous SA on the performance of B and Q, including the effects on ovary development. SA titer was always higher in leaves that were infested with viruliferous B than with viruliferous Q, whereas the SA titer did not differ between leaves infested with non-viruliferous B and Q. The relative gene expression of SA signaling was increased by feeding of viruliferous B but was not increased by feeding of viruliferous Q. The life history traits of B and Q were adversely affected on SA-treated plants. On SA-treated plants, both B and Q had lower fecundity, shorter longevity, longer developmental time and lower survival rate than on untreated plants. Compared with whiteflies feeding on control plants, those feeding on SA-treated plants had fewer oocytes and slower ovary development. On SA-treated plants, viruliferous B had fewer oocytes than viruliferous Q. These results indicate that TYLCV tends to induce SA-regulated plant defense against B but SA-regulated plant defense against Q was reduced. In other words, Q may have a mutualistic relationship with TYLCV that results in the reduction of the plant's defense response.

  10. ACE: an efficient and sensitive tool to detect insecticide resistance-associated mutations in insect acetylcholinesterase from RNA-Seq data.

    PubMed

    Guo, Dianhao; Luo, Jiapeng; Zhou, Yuenan; Xiao, Huamei; He, Kang; Yin, Chuanlin; Xu, Jianhua; Li, Fei

    2017-07-10

    Insecticide resistance is a substantial problem in controlling agricultural and medical pests. Detecting target site mutations is crucial to manage insecticide resistance. Though PCR-based methods have been widely used in this field, they are time-consuming and inefficient, and typically have a high false positive rate. Acetylcholinesterases (Ace) is the neural target of the widely used organophosphate (OP) and carbamate insecticides. However, there is not any software available to detect insecticide resistance associated mutations in RNA-Seq data at present. A computational pipeline ACE was developed to detect resistance mutations of ace in insect RNA-Seq data. Known ace resistance mutations were collected and used as a reference. We constructed a Web server for ACE, and the standalone software in both Linux and Windows versions is available for download. ACE was used to analyse 971 RNA-Seq data from 136 studies in 7 insect pests. The mutation frequency of each RNA-Seq dataset was calculated. The results indicated that the resistance frequency was 30%-44% in an eastern Ugandan Anopheles population, thus suggesting this resistance-conferring mutation has reached high frequency in these mosquitoes in Uganda. Analyses of RNA-Seq data from the diamondback moth Plutella xylostella indicated that the G227A mutation was positively related with resistance levels to organophosphate or carbamate insecticides. The wasp Nasonia vitripennis had a low frequency of resistant reads (<5%), but the agricultural pests Chilo suppressalis and Bemisia tabaci had a high resistance frequency. All ace reads in the 30 B. tabaci RNA-Seq data were resistant reads, suggesting that insecticide resistance has spread to very high frequency in B. tabaci. To the best of our knowledge, the ACE pipeline is the first tool to detect resistance mutations from RNA-Seq data, and it facilitates the full utilization of large-scale genetic data obtained by using next-generation sequencing.

  11. Bensulfuron-Methyl Treatment of Soil Affects the Infestation of Whitefly, Aphid, and Tobacco Mosaic Virus on Nicotiana tabacum

    PubMed Central

    Li, Renyi; Islam, Saif Ul; Wu, Zujian; Ye, Xiujuan

    2016-01-01

    Bensulfuron-methyl (BSM) is widely used in paddy soil for weed control. BSM residue in the soil has been known to inhibit the growth of sensitive crop plants. However, it is unknown whether BSM residue can affect the agrosystem in general. In this study, we have found significant effects of BSM on the infestation of Bemisia tabaci, Myzus persicae, and Tobacco mosaic virus (TMV) in Nicotiana tabacum. The soil was treated with BSM before the pest inoculation. The herbicide-treated tobaccos showed resistance to B. tabaci, but this resistance could not be detected until 15-day post-infestation when smaller number of adults B. tabaci appeared. In M. persicae assay, the longevity of all development stages of insects, and the fecundity of insects were not significantly affected when feeding on BSM-treated plants. In TMV assay, the BSM treatment also reduced virus-induced lesions in early infection time. However, the titer of TMV in BSM treated plants increased greatly over time and was over 40-fold higher than the mock-infected control plants after 20 days. Further studies showed that BSM treatment increased both jasmonic acid (JA) and salicylic acid (SA) levels in tobacco, as well as the expression of target genes in the JA and SA signaling pathways, such as NtWIPK, NtPR1a, and NtPAL. NtPR1a and NtPAL were initially suppressed after virus-inoculation, while NtRDR1 and NtRDR6, which play a key role in fighting virus infection, only showed up- or were down-regulated 20 days post virus-inoculation. Taken together, our results suggested that BSM residue in the soil may affect the metabolism of important phytohormones such as JA and SA in sensitive plants and consequently affect the plant immune response against infections such as whitefly, aphids, and viruses. PMID:28083007

  12. Australian thrips of the Haplothrips lineage (Insecta: Thysanoptera)

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Mound, Laurence A.; Minaei, Kambiz

    2007-12-01

    Water is important and ubiquitous and surprisingly not understood. Just because is it common, does not mean its understood "Poets say science takes away from the beauty of the stars-mere globs of gas atoms. I too can see the stars on a desert night, and feel them. But do I see less or more? ... What is the pattern, or the meaning, or the why? It does not do harm to the mystery to know a little about it. For far more marvelous is the truth than any artists of the past imagined it." - Richard P. Feynman, The Feynmanmore » Lectures on Physics, 1963. (Cited in the introduction to Chapter 3 of "The Snowflake, Winter's Secret Beauty, Text by Kenneth Libbrecht, Photography by Patricia Rasmussen.) 1. Highlight the fact that water is still one of the most active and challenging research areas in chemistry and physics 2. Describe in general terms why water is unique from the point of view of its properties o Large dipole-moment o Very polarizable o Involved in is own chemistry (e.g. auto ionization defining the pH scale) • Atomic view: o Oxygen and Hydrogen. o Hydrogen is a quantum mechanical in nature. Classical physics is no good. o Water’s Charge-charge interaction described by classical physics laws (e.g. Coulomb) o The statistical mechanics of water. Why counting is important. o You need the full arsenal of theoretical methods to understand water • Waters well known bulk properties do not explain waters anomalies o Surface tension, heat capacity • Understanding the microscopic nature of water and how this gives rise to the known bulk quantities is the thrust of state-of-the-art research o Hydrogen bonding o Liquid structure o The so-called “spherical cow” model gets you no where with water o There are 10s-100s of different water models available in the scientific literature. It is a hard business • All of life takes place at the interfaces of solid, liquid, and gas o Biology takes advantage of waters varying properties in different geometries (e.g. confined, surfaces, etc. o Water behaves differently in confined environments • Water is the most abundant greenhouse gas o How does a microscopic understanding of water impact our knowledge of the radiation budget of the earth o How does a microscopic understanding of water impact our knowledge of weather.« less

  13. B Vitamins as Regulators of Phytoplankton Dynamics

    NASA Astrophysics Data System (ADS)

    Panzeca, Caterina; Tovar-Sanchez, Antonio; Agustí, Susana; Reche, Isabel; Duarte, Carlos M.; Taylor, Gordon T.; Sañudo-Wilhelmy, Sergio A.

    2006-12-01

    Without an adequate supply of dissolved vitamins, many species of phytoplankton do not grow. Additions of inorganic nutrients like phosphorus and nitrogen, and trace metals like iron, are not alone adequate to sustain life-a practical lesson learned quickly by experimental biologists when they try to keep eukaryotic phytoplankton cultures alive in their labs. The reason is that coenzymes such as B vitamins are also required for many metabolic pathways. For example, vitamin B1 serves as a cofactor for a large number of enzymatic systems, including the pyruvate dehydrogenase complex required for the metabolism of carbohydrates (glycolysis) and amino acid synthesis [Vandamme, 1989]. Vitamin B12 is used primarily to assist two enzymes: methionine synthase, which is involved in DNA synthesis, and methylmalonyl CoA mutase, which is required for inorganic carbon assimilation [Lindemans and Abels, 1985].

  14. Newer insecticides for plant virus disease management.

    PubMed

    Castle, Steven; Palumbo, John; Prabhaker, Nilima

    2009-05-01

    Effective management of insect and mite vectors of plant pathogens is of crucial importance to minimize vector-borne diseases in crops. Pesticides play an important role in managing vector populations by reducing the number of individuals that can acquire and transmit a virus, thereby potentially lowering disease incidence. Certain insecticides exhibit properties other than lethal toxicity that affect feeding behaviours or otherwise interfere with virus transmission. To evaluate the potential of various treatments against the Bemisia tabaci-transmitted Cucurbit yellow stunting disorder virus (CYSDV), insecticide field trials were conducted in Yuma, AZ, USA, during spring and autumn growing seasons. Differences in vector-intensity each season led to mixed results, but at least five insecticide treatments showed promise in limiting virus spread during spring 2008. Increasing concern among growers in this region regarding recent epidemics of CYSDV is leading to more intensive use of insecticides that threatens to erupt into unmanageable resistance. Sustainability of insecticides is an important goal of pest management and more specifically resistance management, especially for some of the most notorious vector species such as B. tabaci and Myzus persiscae that are likely to develop resistance.

  15. Evaluating Weeds as Hosts of Tomato yellow leaf curl virus.

    PubMed

    Smith, Hugh A; Seijo, Teresa E; Vallad, Gary E; Peres, Natalia A; Druffel, Keri L

    2015-08-01

    Bemisia tabaci (Gennadius) biotype B transmits Tomato yellow leaf curl virus (TYLCV), which affects tomato production globally. Prompt destruction of virus reservoirs is a key component of virus management. Identification of weed hosts of TYLCV will be useful for reducing such reservoirs. The status of weeds as alternate hosts of TYLCV in Florida remains unclear. In greenhouse studies, B. tabaci adults from a colony reared on TYLCV-infected tomato were established in cages containing one of four weeds common to horticultural fields in central and south Florida. Cages containing tomato and cotton were also infested with viruliferous whiteflies as a positive control and negative control, respectively. Whitefly adults and plant tissue were tested periodically over 10 wk for the presence of TYLCV using PCR. After 10 wk, virus-susceptible tomato plants were placed in each cage to determine if whiteflies descended from the original adults were still infective. Results indicate that Bidens alba, Emilia fosbergii, and Raphanus raphanistrum are not hosts of TYLCV, and that Amaranthus retroflexus is a host. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. An Evaluation of Frankliniella occidentalis (Thysanoptera: Thripidae) and Frankliniella intonsa (Thysanoptera: Thripidae) Performance on Different Plant Leaves Based on Life History Characteristics

    PubMed Central

    Li, Wei-Di; Zhang, Peng-Jun; Zhang, Jing-Ming; Zhang, Zhi-Jun; Huang, Fang; Bei, Ya-Wei; Lin, Wen-Cai; Lu, Yao-Bin

    2015-01-01

    To compare the performance of Frankliniella occidentalis (Pergande) and native Frankliniella intonsa (Trybom) on cucumber and tomato leaves in laboratory, life history characters were investigated, and life tables were constructed using the method of age-stage, two-sex table life. Compared with tomato leaf, there were shorter total preoviposition period (TPOP), higher fecundity, longer female longevity, and higher intrinsic rate of increase (r) of both F. occidentalis and F. intonsa on cucumber leaf. Meanwhile, on cucumber leaf, the shorter TPOP, higher fecundity, longer female longevity, and higher value of r were found on population of F. intonsa but on tomato leaf which were found on population of F. occidentalis. From above, cucumber leaf was the preference to population development of both F. occidentalis and F. intonsa compared with tomato leaf. Nevertheless, on cucumber leaf, population of F. intonsa would grow faster than that of F. occidentalis, which was the opposite on tomato leaf. As to the population development in fields, much more factors would be taken into account, such as pollen, insecticide resistance, and effects of natural enemies etc. PMID:25673049

  17. An evaluation of Frankliniella occidentalis (Thysanoptera: Thripidae) and Frankliniella intonsa (Thysanoptera: Thripidae) performance on different plant leaves based on life history characteristics.

    PubMed

    Li, Wei-Di; Zhang, Peng-Jun; Zhang, Jing-Ming; Zhang, Zhi-Jun; Huang, Fang; Bei, Ya-Wei; Lin, Wen-Cai; Lu, Yao-Bin

    2015-01-01

    To compare the performance of Frankliniella occidentalis (Pergande) and native Frankliniella intonsa (Trybom) on cucumber and tomato leaves in laboratory, life history characters were investigated, and life tables were constructed using the method of age-stage, two-sex table life. Compared with tomato leaf, there were shorter total preoviposition period (TPOP), higher fecundity, longer female longevity, and higher intrinsic rate of increase (r) of both F. occidentalis and F. intonsa on cucumber leaf. Meanwhile, on cucumber leaf, the shorter TPOP, higher fecundity, longer female longevity, and higher value of r were found on population of F. intonsa but on tomato leaf which were found on population of F. occidentalis. From above, cucumber leaf was the preference to population development of both F. occidentalis and F. intonsa compared with tomato leaf. Nevertheless, on cucumber leaf, population of F. intonsa would grow faster than that of F. occidentalis, which was the opposite on tomato leaf. As to the population development in fields, much more factors would be taken into account, such as pollen, insecticide resistance, and effects of natural enemies etc. © The Author 2015. Published by Oxford University Press on behalf of the Entomological Society of America.

  18. Identification of a whitefly species by genomic and behavioral studies

    USGS Publications Warehouse

    Perring, T.M.; Cooper, A.D.; Rodriguez, R.J.; Farrar, C.A.; Bellows, T.S.

    1993-01-01

    An introduced whitefly species, responsible for over a half billion dollars in damage to U.S. agricultural production in 1991, is morphologically indistinguishable from Bemisia tabaci (Gennadius). However, with the use of polymerase chain reaction-based DNA differentiation tests, allozymic frequency analyses, crossing experiments, and mating behavior studies, the introduced whitefly is found to be a distinct species. Recognition of this new species, the silverleaf whitefly, is critical in the search for management options.

  19. Full time adult credential students' instructional preferences at California State University, Long Beach: pedagogy orandragogy?

    PubMed

    Wang, Victor

    2004-03-01

    This study investigated the instructional preferences of full time adult credential students after they took a live course called Principles of Adult Education at California State University, Long Beach (CSULB) in the fall semester of 2002. These full time adult credential students had been working on their adult teaching credentials to meet the competencies specified by the California Commission on Teacher Credentialing. The course introduced students to Andragogy developed by Malcolm Knowles out of the andragogical model developed by Lindeman (1926). The study used Principles of Adult Learning Scales (PALS), advanced by Gary Conti in 1983 to measure instructional preferences. Data were collected from 30 (100% of 30) full time adult credential students enrolled in a live course to determine their instructional preferences of helping adults learn. The results of the study showed in most cases these adult learning professionals taught adult students andragogically; in some cases they taught adult students pedagogically.

  20. Plant-mediated horizontal transmission of Rickettsia endosymbiont between different whitefly species.

    PubMed

    Li, Yi-Han; Ahmed, Muhammad Z; Li, Shao-Jian; Lv, Ning; Shi, Pei-Qiong; Chen, Xiao-Sheng; Qiu, Bao-Li

    2017-12-01

    A growing number of studies have revealed the presence of closely related endosymbionts in phylogenetically distant arthropods, indicating horizontal transmission of these bacteria. Here we investigated the interspecific horizontal transmission of Rickettsia between two globally invasive whitefly species, Bemisia tabaci MEAM1 and B. tabaci MED, via cotton plants. We found both scattered and confined distribution patterns of Rickettsia in these whiteflies. After entering cotton leaves, Rickettsia was restricted to the leaf phloem vessels and could be taken up by both species of the Rickettsia-free whitefly adults, but only the scattered pattern was observed in the recipient whiteflies. Both the relative quantity of Rickettsia and the efficiency of transmitting Rickettsia into cotton leaves were significantly higher in MEAM1 females than in MED females. The retention time of Rickettsia transmitted from MEAM1 into cotton leaves was at least 5 days longer than that of MED. Phylogenetic analysis based on 16S rRNA and gltA genes confirmed that the Rickettsia extracted from the donor MEAM1, the cotton leaves, the recipient MEAM1 and the recipient MED were all identical. We conclude that cotton plants can mediate horizontal transmission of Rickettsia between different insect species, and that the transmission dynamics of Rickettsia vary with different host whitefly species. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  1. A simple, rapid and inexpensive method for localization of Tomato yellow leaf curl virus and Potato leafroll virus in plant and insect vectors.

    PubMed

    Ghanim, Murad; Brumin, Marina; Popovski, Smadar

    2009-08-01

    A simple, rapid, inexpensive method for the localization of virus transcripts in plant and insect vector tissues is reported here. The method based on fluorescent in situ hybridization using short DNA oligonucleotides complementary to an RNA segment representing a virus transcript in the infected plant or insect vector. The DNA probe harbors a fluorescent molecule at its 5' or 3' ends. The protocol: simple fixation, hybridization, minimal washing and confocal microscopy, provides a highly specific signal. The reliability of the protocol was tested by localizing two phloem-limited plant virus transcripts in infected plants and insect tissues: Tomato yellow leaf curl virus (TYLCV) (Begomovirus: Geminiviridae), exclusively transmitted by the whitefly Bemisia tabaci (Gennadius) in a circulative non-propagative manner, and Potato leafroll virus (Polerovirus: Luteoviridae), similarly transmitted by the aphid Myzus persicae (Sulzer). Transcripts for both viruses were localized specifically to the phloem sieve elements of infected plants, while negative controls showed no signal. TYLCV transcripts were also localized to the digestive tract of B. tabaci, confirming TYLCV route of transmission. Compared to previous methods for localizing virus transcripts in plant and insect tissues that include complex steps for in-vitro probe preparation or antibody raising, tissue fixation, block preparation, sectioning and hybridization, the method described below provides very reliable, convincing, background-free results with much less time, effort and cost.

  2. Zoophytophagous mirids provide pest control by inducing direct defences, antixenosis and attraction to parasitoids in sweet pepper plants.

    PubMed

    Bouagga, Sarra; Urbaneja, Alberto; Rambla, José L; Flors, Víctor; Granell, Antonio; Jaques, Josep A; Pérez-Hedo, Meritxell

    2018-06-01

    In addition to their services as predators, mirid predators are able to induce plant defences by phytophagy. However, whether this induction occurs in sweet pepper and whether it could be an additional benefit to their role as a biological control agent in this crop remain unknown. Here, these questions were investigated in two model insects, the mirids Nesidiocoris tenuis and Macrolophus pygmaeus. Plant feeding behaviour was observed in both N. tenuis and M. pygmaeus on sweet pepper and occupied 33% and 14% of total time spent on the plant, respectively. The punctures caused by mirid plant feeding induced the release of a blend of volatile organic compounds (VOCs) which repelled the herbivore pests Frankliniella occidentalis and Bemisia tabaci and attracted the whitefly parasitoid Encarsia formosa. The repellent effect on B. tabaci was observed for at least 7 days after initial exposure of the plant to N. tenuis, and attraction of E. formosa remained functional for 14 days. Plant defences induced by the feeding of mirid predators, their subsequent effects on the behaviour of both pests and natural enemies, and the persistence of these observed effects open the door to new control strategies in the sweet pepper crop. Further application of this research is discussed, such as the vaccination of plants by zoophytophagous mirids in the nursery before transplantation. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  3. Structure of the mouthparts of Frankliniella bispinosa (Morgan) (Thysanoptera: Thripidae)

    Treesearch

    Carl C. Childers; Diann S. Achor

    1991-01-01

    Thrips are increasingly recognized as potentially serious pests in a number of different agricultural, ornamental and sylvan commodities worldwide as indicated by the papers presented at this conference. The small size of thrips, their large numbers, capacity for flight and wind dispersal, wide host ranges, poorly understood life histories and probable potential for...

  4. Inheritance of resistance to acrinathrin in Frankliniella occidentalis (Thysanoptera: Thripidae).

    PubMed

    Bielza, Pablo; Quinto, Vicente; Fernández, Esther; Grávalos, Carolina; Abellán, Jaime; Cifuentes, Dina

    2008-05-01

    The western flower thrips (WFT), Frankliniella occidentalis (Pergande), is an economically important pest. The genetic basis of acrinathrin resistance was investigated in WFT. The resistant strain, selected in the laboratory for acrinathrin resistance from a pool of thrips populations collected in Almeria (south-eastern Spain), showed a high resistance to acrinathrin (43-fold based on LC(50) values) compared with the laboratory susceptible strain. Mortality data from reciprocal crosses of resistant and susceptible thrips indicated that resistance was autosomal and not influenced by maternal effects. Analysis of probit lines from the parental strains and reciprocal crosses showed that resistance was expressed as a codominant trait. To determine the number of genes involved, a direct test of monogenic inheritance based on the backcrosses suggested that resistance to acrinathrin was probably controlled by one locus. Another approach, which was based on phenotypic variances, showed n(E), or the minimum number of freely segregating genetic factors for the resistant strain, to be 0.79. The results showed that acrinathrin resistance in WFT was autosomal and not influenced by maternal effects, and was expressed as a codominant trait, probably controlled by one locus. Copyright (c) 2008 Society of Chemical Industry.

  5. Development of Near-Isogenic Lines in a Parthenogenetically Reproduced Thrips Species, Frankliniella occidentalis

    PubMed Central

    Yuan, Guangdi; Wan, Yanran; Li, Xiaoyu; He, Bingqing; Zhang, Youjun; Xu, Baoyun; Wang, Shaoli; Xie, Wen; Zhou, Xuguo; Wu, Qingjun

    2017-01-01

    Although near-isogenic lines (NILs) can standardize genetic backgrounds among individuals, it has never been applied in parthenogenetically reproduced animals. Here, through multiple rounds of backcrossing and spinosad screening, we generated spinosad resistant NILs in the western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), with a haplo-diploid reproduction system. The resultant F. occidentalis NIL-R strain maintained a resistance ratio over 30,000-fold, which was comparable to its parental resistant strain, Spin-R. More importantly, F. occidentalis NIL-R shared 98.90% genetic similarity with its susceptible parental strain Ivf03. By developing this toolset, we are able to segregate individual resistance and facilitate the mechanistic study of insecticide resistances in phloem-feeding arthropods, a group of devastating pest species reproducing sexually as well as asexually. PMID:28348528

  6. Development of Near-Isogenic Lines in a Parthenogenetically Reproduced Thrips Species, Frankliniella occidentalis.

    PubMed

    Yuan, Guangdi; Wan, Yanran; Li, Xiaoyu; He, Bingqing; Zhang, Youjun; Xu, Baoyun; Wang, Shaoli; Xie, Wen; Zhou, Xuguo; Wu, Qingjun

    2017-01-01

    Although near-isogenic lines (NILs) can standardize genetic backgrounds among individuals, it has never been applied in parthenogenetically reproduced animals. Here, through multiple rounds of backcrossing and spinosad screening, we generated spinosad resistant NILs in the western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), with a haplo-diploid reproduction system. The resultant F. occidentalis NIL-R strain maintained a resistance ratio over 30,000-fold, which was comparable to its parental resistant strain, Spin-R. More importantly, F. occidentalis NIL-R shared 98.90% genetic similarity with its susceptible parental strain Ivf03. By developing this toolset, we are able to segregate individual resistance and facilitate the mechanistic study of insecticide resistances in phloem-feeding arthropods, a group of devastating pest species reproducing sexually as well as asexually.

  7. Decomposition

    USGS Publications Warehouse

    Middleton, Beth A.

    2014-01-01

    A cornerstone of ecosystem ecology, decomposition was recognized as a fundamental process driving the exchange of energy in ecosystems by early ecologists such as Lindeman 1942 and Odum 1960). In the history of ecology, studies of decomposition were incorporated into the International Biological Program in the 1960s to compare the nature of organic matter breakdown in various ecosystem types. Such studies still have an important role in ecological studies of today. More recent refinements have brought debates on the relative role microbes, invertebrates and environment in the breakdown and release of carbon into the atmosphere, as well as how nutrient cycling, production and other ecosystem processes regulated by decomposition may shift with climate change. Therefore, this bibliography examines the primary literature related to organic matter breakdown, but it also explores topics in which decomposition plays a key supporting role including vegetation composition, latitudinal gradients, altered ecosystems, anthropogenic impacts, carbon storage, and climate change models. Knowledge of these topics is relevant to both the study of ecosystem ecology as well projections of future conditions for human societies.

  8. Practice-based learning and improvement: a dream that can become a reality.

    PubMed

    Manning, Phil R

    2003-01-01

    Systematically enhancing learning from experience (practice-based learning) dominates the teachings of Sir William Osler and adult learning theorists such as Eduard Lindeman, Malcolm Knowles, and Cyril Houle. Because of time constraints, most physicians have not implemented methods that systematically facilitate learning from day-to-day work, but improvements in information technology offer the promise of making systematic practice-based learning practical. At least four ingredients need to be incorporated to significantly enhance learning from experience: a database that makes it possible to study individual practices; methods for supplying short, quick answers to questions while seeing patients; a reminder system to avoid errors of omission; and the opportunity to discuss practice data with colleagues. Great progress has been made, but significant barriers still must be overcome before a majority of physicians will participate. In particular, methods of data collection must be simplified, the delivery of point-of-care information and reminders must become more automatic, and physicians must develop skills to make the discussion of practice data acceptable, stimulating, and not unduly punitive.

  9. Diversity and localization of bacterial symbionts in three whitefly species (Hemiptera: Aleyrodidae) from the east coast of the Adriatic Sea.

    PubMed

    Skaljac, M; Zanić, K; Hrnčić, S; Radonjić, S; Perović, T; Ghanim, M

    2013-02-01

    Several whitefly species (Hemiptera: Aleyrodidae) are cosmopolitan phloem-feeders that cause serious damage in numerous agricultural crops. All whitefly species harbor a primary bacterial symbiont and a diverse array of secondary symbionts which may influence several aspects of the insect's biology. We surveyed infections by secondary symbionts in Bemisia tabaci (Gennadius), Trialeurodes vaporariorum (Westwood) and Siphoninus phillyreae (Haliday) from areas in the east cost of the Adriatic Sea. Both the Middle East-Asia Minor 1 (MEAM1) and Mediterranean (MED) B. tabaci genetic groups were detected in Montenegro, whereas only the MED was confirmed in Croatia. Trialeurodes vaporariorum and S. phillyreae were found in all areas surveyed. MEAM1 and MED exhibited similarity to previously reported infections, while populations of T. vaporariorum from Montenegro harbored Rickettsia, Wolbachia and Cardinium in addition to previously reported Hamiltonella and Arsenopnohus. Siphoninus phillyreae harbored Hamiltonella, Wolbachia, Cardinium and Arsenophonus, with the latter appearing in two alleles. Multiple infections of all symbionts were common in the three insect species tested, with some reaching near fixation. Florescent in situ hybridization showed new localization patterns for Hamiltonella in S. phillyreae, and the morphology of the bacteriosome differed from that observed in other whitefly species. Our results show new infections with bacterial symbionts in the whitefly species studied. Infections with the same symbionts in reproductively isolated whitefly species confirm complex relationships between whiteflies and bacterial symbionts, and suggest possible horizontal transfer of some of these bacteria.

  10. Prey preference of the predatory mite, Amblyseius swirskii between first instar western flower thrips Frankliniella occidentalis and nymphs of the twospotted spider mite Tetranychus urticae.

    PubMed

    Xu, Xuenong; Enkegaard, Annie

    2010-01-01

    The prey preference of polyphagous predators plays an important role in suppressing different species of pest insects. In this study the prey preference of the predatory mite, Amblyseius swirskii (Athias-Henriot) (Acari: Phytoseiidae) was examined between nymphs of the twospotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae) and first instar larvae of the western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), as well as between active and chrysalis spider mite protonymphs and active and chrysalis spider mite deutonymphs. The study was done in the laboratory on bean leaf discs at 25 ± 1° C and 70 ± 5% RH. Amblyseius swirskii had a clear preference for thrips compared to both spider mite protonymphs and deutonymphs. About twice as many thrips as spider mites were consumed. Amblyseius swirskii did not show a preference between active and chrysalis stages of spider mites.

  11. Effects of pine pollen supplementation in an onion diet on Frankliniella fusca reproduction.

    PubMed

    Angelella, G M; Riley, D G

    2010-04-01

    A micro-cage bioassay was developed to test the effect of slash pine pollen (Pinus elliottii Engelm.) supplementation to a whole onion plant (Allium cepa L. variety Pegasus) diet on thrips (Thysanoptera: Thripidae) reproductive parameters. Frankliniella fusca (Hinds) females were placed on two to three-leaf stage onion seedling under a treatment of either slash pine (Pinus elliottii Engelm.) pollen dusting (a pollen supplement) or no pollen treatment. Adult survival, net oviposition, and offspring produced over a series of ten 2-d intervals were recorded. From these values, l(x), l(x)m(x), and R(0) values were constructed. A trimodal distribution of oviposition was observed with the pollen supplement. Increased oviposition rates led to higher female offspring production per female and to a four-fold increase in F. fusca net reproduction on pollen-treated onions.

  12. The autophagy pathway participates in resistance to tomato yellow leaf curl virus infection in whiteflies.

    PubMed

    Wang, Lan-Lan; Wang, Xin-Ru; Wei, Xue-Mei; Huang, Huang; Wu, Jian-Xiang; Chen, Xue-Xin; Liu, Shu-Sheng; Wang, Xiao-Wei

    2016-09-01

    Macroautophagy/autophagy plays an important role against pathogen infection in mammals and plants. However, little has been known about the role of autophagy in the interactions of insect vectors with the plant viruses, which they transmit. Begomoviruses are a group of single-stranded DNA viruses and are exclusively transmitted by the whitefly Bemisia tabaci in a circulative manner. In this study, we found that the infection of a begomovirus, tomato yellow leaf curl virus (TYLCV) could activate the autophagy pathway in the Middle East Asia Minor 1 (MEAM1) species of the B. tabaci complex as evidenced by the formation of autophagosomes and ATG8-II. Interestingly, the activation of autophagy led to the subsequent degradation of TYLCV coat protein (CP) and genomic DNA. While feeding the whitefly with 2 autophagy inhibitors (3-methyladenine and bafilomycin A1) and silencing the expression of Atg3 and Atg9 increased the viral load; autophagy activation via feeding of rapamycin notably decreased the amount of viral CP and DNA in the whitefly. Furthermore, we found that activation of whitefly autophagy could inhibit the efficiency of virus transmission; whereas inhibiting autophagy facilitated virus transmission. Taken together, these results indicate that TYLCV infection can activate the whitefly autophagy pathway, which leads to the subsequent degradation of virus. Furthermore, our report proves that an insect vector uses autophagy as an intrinsic antiviral program to repress the infection of a circulative-transmitted plant virus. Our data also demonstrate that TYLCV may replicate and trigger complex interactions with the insect vector.

  13. Genome Evolution in the Primary Endosymbiont of Whiteflies Sheds Light on Their Divergence

    PubMed Central

    Santos-Garcia, Diego; Vargas-Chavez, Carlos; Moya, Andrés; Latorre, Amparo; Silva, Francisco J.

    2015-01-01

    Whiteflies are important agricultural insect pests, whose evolutionary success is related to a long-term association with a bacterial endosymbiont, Candidatus Portiera aleyrodidarum. To completely characterize this endosymbiont clade, we sequenced the genomes of three new Portiera strains covering the two extant whitefly subfamilies. Using endosymbiont and mitochondrial sequences we estimated the divergence dates in the clade and used these values to understand the molecular evolution of the endosymbiont coding sequences. Portiera genomes were maintained almost completely stable in gene order and gene content during more than 125 Myr of evolution, except in the Bemisia tabaci lineage. The ancestor had already lost the genetic information transfer autonomy but was able to participate in the synthesis of all essential amino acids and carotenoids. The time of divergence of the B. tabaci complex was much more recent than previous estimations. The recent divergence of biotypes B (MEAM1 species) and Q (MED species) suggests that they still could be considered strains of the same species. We have estimated the rates of evolution of Portiera genes, synonymous and nonsynonymous, and have detected significant differences among-lineages, with most Portiera lineages evolving very slowly. Although the nonsynonymous rates were much smaller than the synonymous, the genomic dN/dS ratios were similar, discarding selection as the driver of among-lineage variation. We suggest variation in mutation rate and generation time as the responsible factors. In conclusion, the slow evolutionary rates of Portiera may have contributed to its long-term association with whiteflies, avoiding its replacement by a novel and more efficient endosymbiont. PMID:25716826

  14. Fitness Trade-Off Associated With Spinosad Resistance in Frankliniella occidentalis (Thysanoptera: Thripidae).

    PubMed

    Li, Xiaoyu; Wan, Yanran; Yuan, Guangdi; Hussain, Sabir; Xu, Baoyun; Xie, Wen; Wang, Shaoli; Zhang, Youjun; Wu, Qingjun

    2017-08-01

    Frankliniella occidentalis (Pergande) is an economically important pest of agricultural crops. High resistance has been detected in field populations of F. occidentalis against the insecticide spinosad. In this study, we compared life history traits, body sizes, and feeding behaviors (recorded via an electrical penetration graph) of spinosad-susceptible (Ivf03) and spinosad-resistant (NIL-R) near-isogenic lines of F. occidentalis. Life table analysis showed that NIL-R had reduced female longevity and reduced fecundity. The relative fitness of NIL-R (0.43) was less than half that of Ivf03. NIL-R individuals were smaller than Ivf03 individuals, both in body length and body width at every stage. The number and duration of feeding activities were significantly reduced in NIL-R, with the exception of total duration of long-ingestion probes. These results suggest that there is a fitness trade-off associated with spinosad resistance in F. occidentalis, and that the development of resistance in this pest species may be reduced by rotating spinosad with other pesticides lacking cross-resistance. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  15. Proteomic Analysis Reveals Resistance Mechanism Against Chlorpyrifos in Frankliniella occidentalis (Thysanoptera: Thripidae).

    PubMed

    Yan, Dan-Kan; Hu, Min; Tang, Yun-Xia; Fan, Jia-Qin

    2015-08-01

    The western flower thrips is an economically important worldwide pest of many crops, and chlorpyrifos has been used to control western flower thrips for many years. To develop a better resistance-management strategy, a chlorpyrifos-resistant strain of western flower thrips (WFT-chl) was selected in the laboratory. More than 39-fold resistance was achieved after selected by chlorpyrifos for 19 generations in comparison with the susceptible strain (WFT-S). Proteome of western flower thrips (WFT-S and WFT-chl) was investigated using a quantitative proteomics approach with isobaric tag for relative and absolute quantification technique and liquid chromatography-tandem mass spectrometry technologies. According to the functional analysis, 773 proteins identified were grouped into 10 categories of molecular functions and 706 proteins were presented in 213 kinds of pathways. Comparing the proteome of WFT-chl with that of WFT-S, a total of eight proteins were found up-regulated and three down-regulated. The results from functional annotation and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses indicated that the differentially expressed protein functions in binding, catalyzing, transporting, and enzyme regulation were most important in resistance development. A list of proteins functioning in biological processes of metabolism, biological regulation, and response to stimulus was found in WFT-chl, suggesting that they are possibly the major components of the resistance mechanism to chlorpyrifos in western flower thrips. Notably, several novel potential resistance-related proteins were identified such as ribosomal protein, Vg (vitellogenin), and MACT (muscle actin), which can be used to improve our understanding of the resistance mechanisms in western flower thrips. This study provided the first comprehensive view of the complicated resistance mechanism employed by WFT-S and WFT-chl through the isobaric tag for relative and absolute quantification coupled with liquid chromatography-tandem mass spectrometry technologies. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. Cross-resistance and baseline susceptibility of spirotetramat in Frankliniella occidentalis (Thysanoptera: Thripidae).

    PubMed

    Guillén, Juan; Navarro, Miguel; Bielza, Pablo

    2014-06-01

    Western flower thrips, Frankliniella occidentalis (Pergande), is an economically important pest all over the world. New products against thrips are necessary, as there are few effective compounds exhibiting cross-resistance among them. Lethal effects, cross-resistance, and baseline susceptibility to spirotetramat were evaluated in this study. A new bioassay method for testing thrips against spirotetramat was developed. Spirotetramat showed a significant mortality effect on larvae after 7 d of exposure, but a low effect was observed on adults. Baseline results for larval instars showed LC50 values ranging from 11.59 to 49.81 mg AI/liter, with a low natural variability (3.2-fold). Cross-resistance studies showed overlapping confidence limits of the LC50 values for laboratory-selected (against acrinathrin, methiocarb, formetanate, and spinosad) resistant and susceptible strains, and low resistance factors, from 0.5 to 1.9, suggesting no cross-resistance to conventional insecticides previously used. A slight ovicidal effect (21-40% reduction) was also detected. Despite presenting low effects on adults, spirotetramat showed high but slow efficacy on F. occidentalis larvae. Field populations in southeast Spain showed a consistent susceptibility to spirotetramat. Given the scarcity of effective products and the lack of cross-resistance to other insecticides, spirotetramat can be considered as a good chemical tool to control F. occidentalis.

  17. Seasonal Population Dynamics of Thrips (Thysanoptera) in Wisconsin and Iowa Soybean Fields.

    PubMed

    Bloomingdale, Chris; Irizarry, Melissa D; Groves, Russell L; Mueller, Daren S; Smith, Damon L

    2017-02-01

    With the discovery of Neohydatothrips variabilis (Beach) as a vector of Soybean vein necrosis virus (Family Bunyaviridae Genus Tospovirus), a relatively new pathogen of soybean, a multiyear study was initiated in Wisconsin (2013 and 2014) and Iowa (2014 and 2015) to determine the phenology and species composition of thrips in soybean fields. Yellow sticky card traps were used to sample thrips at regular intervals in five counties within each state's primary soybean-growing region. The assemblage of species present in Wisconsin was determined in all site-years, revealing that N. variabilis and other known vectors of tospoviruses were a relatively small percentage of the total thrips captures in 2013 (1.6%) and 2014 (3.6%). A repeated measures analysis was conducted on cumulative proportion thrips capture data within each state's sampling year to investigate differences in phenology, and standardized cumulative insect days were analyzed between sampling years within each state to determine differences in the relative magnitude of populations. Distinct seasonal trends were not detected based on location, as originally hypothesized, and thrips populations varied significantly among locations and between years. These results suggest that thrips populations may be overwintering in northern climates instead of relying solely on migrations to colonize northern soybean fields. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  18. Space, time and thrips: biogeographic issues in the evolutionary ecology of Thysanoptera

    Treesearch

    John R. Grehan

    1991-01-01

    Most participants of this symposium will be concerned with understanding thrips ecology primarily in order to develop practical and effective control strategies. Questions dealing with historical aspects (evolution) may seem of only isolated "theoretical" interest with little significance for everyday pragmatic concerns. Evolutionary theory is widely...

  19. Remote sensing for detecting and mapping whitefly (Bemisia tabaci) infestations

    USDA-ARS?s Scientific Manuscript database

    Remote sensing technology has long been used for detecting insect infestations on agricultural crops. With recent advances in remote sensing sensors and other spatial information technologies such as Global Position Systems (GPS) and Geographic Information Systems (GIS), remote sensing is finding mo...

  20. Six New Record Species of Whiteflies (Hemiptera: Aleyrodidae) Infesting Morus alba in China

    PubMed Central

    Wang, Ji-Rui; Song, Zao-Qin; Du, Yu-Zhou

    2014-01-01

    Abstract To determine the species of whiteflies occurring on mulberry, Morus alba L. (Rosales: Moraceae) in China, we collected samples in more than 87 sites in 16 provinces of China from 2008 to 2011. In total, 10 species, representing seven genera of the subfamily Aleyrodinae, were identified. Of these, six species are newly recorded on mulberry in China, namely, Aleuroclava ficicola Takahashi, Aleuroclava gordoniae (Takahashi), Aleurotrachelus camelliae (Kuwana), Bemisia afer (Priesner & Hosny), Bemisia tabaci Gennadius, and Pealius machili Takahashi. Information on the taxonomy, distribution, and host plants of the whitefly species found on mulberry in China, along with a brief description and illustrations of each species are provided. PMID:25368095

  1. Elevated air temperature alters an old-field insect community in a multi-factor climate change experiment

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Villalpando, Sean; Williams, Ray; Norby, Richard J

    To address how multiple, interacting climate drivers may affect plant-insect community associations, we sampled the insect community from a constructed old-field plant community grown under simultaneous [CO2], temperature, and water manipulation. Insects were identified to morphospecies, assigned to feeding guilds and abundance, richness and evenness quantified. Warming significantly increased Order Thysanoptera abundance and reduced overall morphospecies richness and evenness. Non-metric multidimensional scaling clearly supported the effect of warming on insect community composition. Reductions in richness for herbivores and parasitoids suggest trophic-level effects within the insect community. Analysis of dominant insects demonstrated the effects of warming were limited to a relativelymore » small number of morphospecies. Reported reductions in whole-community foliar N at elevated [CO2] unexpectedly did not result in any effects on herbivores. These results demonstrate climatic warming may alter certain insect communities via effects on insect species most responsive to higher temperature, contributing to a change in community structure.« less

  2. Phylogenetic relationships of Hemiptera inferred from mitochondrial and nuclear genes.

    PubMed

    Song, Nan; Li, Hu; Cai, Wanzhi; Yan, Fengming; Wang, Jianyun; Song, Fan

    2016-11-01

    Here, we reconstructed the Hemiptera phylogeny based on the expanded mitochondrial protein-coding genes and the nuclear 18S rRNA gene, separately. The differential rates of change across lineages may associate with long-branch attraction (LBA) effect and result in conflicting estimates of phylogeny from different types of data. To reduce the potential effects of systematic biases on inferences of topology, various data coding schemes, site removal method, and different algorithms were utilized in phylogenetic reconstruction. We show that the outgroups Phthiraptera, Thysanoptera, and the ingroup Sternorrhyncha share similar base composition, and exhibit "long branches" relative to other hemipterans. Thus, the long-branch attraction between these groups is suspected to cause the failure of recovering Hemiptera under the homogeneous model. In contrast, a monophyletic Hemiptera is supported when heterogeneous model is utilized in the analysis. Although higher level phylogenetic relationships within Hemiptera remain to be answered, consensus between analyses is beginning to converge on a stable phylogeny.

  3. Real-time PCR assay for distinguishing Frankliniella occidentalis and Thrips palmi Arnika Przybylska, Żaneta Fiedler, Aleksandra Obrępalska-Stęplowska.

    PubMed

    Przybylska, Arnika; Fiedler, Żaneta; Frąckowiak, Patryk; Obrępalska-Stęplowska, Aleksandra

    2018-06-01

    Thrips palmi and Frankliniella occidentalis (order Thysanoptera) are thrips species that represent major plant pests. They are polyphagous insects capable of adversely affecting crop production. As such, in the European Union, these thrips species should be regulated as quarantine organisms. T. palmi and F. occidentalis can cause considerable damage to susceptible plants by feeding on them and transmitting several viruses responsible for serious plant diseases. Successful pest control strategies are based on an early, fast, and reliable diagnosis, which precedes the selection of appropriate steps to limit the effects of harmful organisms. We herein describe a novel diagnostic approach that enables the sensitive and species-specific detection (and differentiation) of these pests in a duplex polymerase chain reaction assay, which was adapted for both standard and real-time quantitative assays. Our method is based on the amplification of a 5.8S-internal transcribed spacer 2 ribosomal DNA fragment that is conserved between T. palmi and F. occidentalis.

  4. Leaf chemistry and foliage avoidance by the thrips Frankliniella occidentalis and Heliothrips haemorrhoidalis in glasshouse collections.

    PubMed

    Brown, Alison S Scott; Veitch, Nigel C; Simmonds, Monique S J

    2011-03-01

    Observational studies on foliage avoidance by the polyphagous thrips species Frankliniella occidentalis (Pergande) and Heliothrips haemorrhoidalis (Bouché) (Thysanoptera: Thripidae) identified six non-host species (Allagopappus dichotomus (Asteraceae), Gardenia posoquerioides (Rubiaceae), Plectranthus aff. barbatus, Plectranthus strigosus, Plectranthus zuluensis (Lamiaceae), and Sclerochiton harveyanus (Acanthaceae) among plants growing within a major glasshouse botanical collection. The effects of sequentially obtained acetone and aqueous methanol leaf extracts on mortality in first instar Frankliniella occidentalis were assessed. The acetone leaf extract of Sclerochiton harveyanus, which had the highest activity against the thrips, yielded four new iridoids, sclerochitonosides A-C, and sclerochitonoside B 4'-methyl ether. Mortality of F. occidentalis was increased on exposure to all four iridoids, and the most active iridoid was sclerochitonoside A (8-epiloganic acid 4'-hydroxyphenylethyl ester). Choice experiments demonstrated that this compound did not significantly deter H. haemorrhoidalis from treated leaf surfaces. The significance of iridoids in the defense mechanism of plants against thrips is discussed.

  5. Predatory mites double the economic injury level of Frankliniella occidentalis in strawberry.

    PubMed

    Sampson, Clare; Kirk, William D J

    2016-01-01

    The western flower thrips Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) causes bronzing to strawberry fruit. Management of insecticide-resistant strains relies on the integration of predators with carefully timed use of the few insecticides available. Effective management requires better understanding of economic injury levels (EILs) and the factors that affect them. The densities of F. occidentalis and the predatory mite Neoseiulus cucumeris (Oudemans) (Acari: Phytoseiidae) were manipulated in field experiments. All stages of flower and fruit were susceptible to thrips damage, but larvae caused nearly twice as much damage as adults per individual. The EIL was about four adult thrips per flower in the absence of predators, but increased to over eight at densities of N. cucumeris typical of good establishment in crops. The EIL could be increased by about 0.7 adult thrips per flower for every N. cucumeris per flower. The results were supported by measurements of EILs in commercial crops.

  6. Floral scent compounds of Amazonian Annonaceae species pollinated by small beetles and thrips.

    PubMed

    Jürgens, A; Webber, A C; Gottsberger, G

    2000-11-01

    Chemical analysis (GC-MS) yielded a total of 58 volatile compounds in the floral scents of six species of Annonaceae distributed in four genera (Xylopia, Anaxagorea, Duguetia, and Rollinia), Xylopia aromatica is pollinated principally by Thysanoptera and secondarily by small beetles (Nitidulidae and Staphylinidae), whereas the five other species were pollinated by Nitidulidae and Staphylinidae only. Although the six Annonaceae species attract a similar array of pollinator groups, the major constituents of their floral scents are of different biochemical origin. The fragrances of flowers of Anaxagorea brevipes and Anaxagorea dolichocarpa were dominated by esters of aliphatic acids (ethyl 2-methylbutanoate, ethyl 3-methylbutanoate), which were not detected in the other species. Monoterpenes (limonene, p-cymene, alpha-pinene) were the main scent compounds of Duguetia asterotricha, and naphthalene prevailed in the scent of Rollinia insignis flowers. The odors of X. aromatica and Xylopia benthamii flowers were dominated by high amounts of benzenoids (methylbenzoate, 2-phenylethyl alcohol).

  7. Transcriptomic Analysis of the Salivary Glands of an Invasive Whitefly

    PubMed Central

    Su, Yun-Lin; Li, Jun-Min; Li, Meng; Luan, Jun-Bo; Ye, Xiao-Dong; Wang, Xiao-Wei; Liu, Shu-Sheng

    2012-01-01

    Background Some species of the whitefly Bemisia tabaci complex cause tremendous losses to crops worldwide through feeding directly and virus transmission indirectly. The primary salivary glands of whiteflies are critical for their feeding and virus transmission. However, partly due to their tiny size, research on whitefly salivary glands is limited and our knowledge on these glands is scarce. Methodology/Principal Findings We sequenced the transcriptome of the primary salivary glands of the Mediterranean species of B. tabaci complex using an effective cDNA amplification method in combination with short read sequencing (Illumina). In a single run, we obtained 13,615 unigenes. The quantity of the unigenes obtained from the salivary glands of the whitefly is at least four folds of the salivary gland genes from other plant-sucking insects. To reveal the functions of the primary glands, sequence similarity search and comparisons with the whole transcriptome of the whitefly were performed. The results demonstrated that the genes related to metabolism and transport were significantly enriched in the primary salivary glands. Furthermore, we found that a number of highly expressed genes in the salivary glands might be involved in secretory protein processing, secretion and virus transmission. To identify potential proteins of whitefly saliva, the translated unigenes were put into secretory protein prediction. Finally, 295 genes were predicted to encode secretory proteins and some of them might play important roles in whitefly feeding. Conclusions/Significance: The combined method of cDNA amplification, Illumina sequencing and de novo assembly is suitable for transcriptomic analysis of tiny organs in insects. Through analysis of the transcriptome, genomic features of the primary salivary glands were dissected and biologically important proteins, especially secreted proteins, were predicted. Our findings provide substantial sequence information for the primary salivary glands

  8. Herbivore Damage and Prior Egg Deposition on Host Plants Influence the Oviposition of the Generalist Moth Trichoplusia ni (Lepidoptera: Noctuidae).

    PubMed

    Coapio, Guadalupe G; Cruz-López, Leopoldo; Guerenstein, Pablo; Malo, Edi A; Rojas, Julio C

    2016-12-01

    Female insects have the difficult task of locating host plants that maximize the survival and success of their offspring. In this study, the oviposition preferences of the cabbage looper moth, Trichoplusia ni (Hübner), for soybean plants, Glycine max (L.), under various treatments-undamaged, mechanically damaged, damaged by T. ni or Spodoptera frugiperda (Smith) larvae or by Bemisia tabaci (Gennadius) adults, egg-free plants, and plants previously oviposited by conspecific or heterospecific females (S. frugiperda)-were investigated using two-choice tests. Additionally, the volatile compounds emitted by the plants under the different treatments were identified by gas chromatography-mass spectrometry. Our results showed that females showed no preferences for undamaged or mechanically damaged plants. However, they oviposited more often on undamaged plants than on those previously damaged by T. ni, S. frugiperda, or B. tabaci. In contrast, females preferred to oviposit on plants previously oviposited by conspecific and heterospecific females than on egg-free plants. Plants damaged by conspecific or heterospecific larvae emitted methyl salicylate, indole, and octyl butyrate, compounds not released by undamaged or mechanically damaged plants. Whitefly damage induced the release of higher quantities of Z(3)-hexenyl acetate, (R)-(+)-limonene, and (E)-β-ocimene compared to plants damaged by larvae and suppressed the emission of linalool. Egg deposition by conspecific and heterospecific moths induced the emission of (R)-(+)-limonene, octyl butyrate, and geranyl acetone but suppressed the release of linalool. This study showed that a generalist moth species can discriminate between plants of different quality, and suggests that females use volatile compounds as cues during this process. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  9. Analysis of Whitefly Transcriptional Responses to Beauveria bassiana Infection Reveals New Insights into Insect-Fungus Interactions

    PubMed Central

    Zhang, Shan; Li, Fang-Fang; Feng, Ming-Guang; Wang, Xiao-Wei; Liu, Shu-Sheng

    2013-01-01

    Background The fungal pathogen, Beauveria bassiana, is an efficient biocontrol agent against a variety of agricultural pests. A thorough understanding of the basic principles of insect-fungus interactions may enable the genetic modification of Beauveria bassiana to enhance its virulence. However, the molecular mechanism of insect response to Beauveria bassiana infection is poorly understood, let alone the identification of fungal virulent factors involved in pathogenesis. Methodology/Principal Findings Here, next generation sequencing technology was applied to examine the expression of whitefly (Bemisia tabaci) genes in response to the infection of Beauveria bassiana. Results showed that, compared to control, 654 and 1,681genes were differentially expressed at 48 hours and 72 hours post-infected whiteflies, respectively. Functional and enrichment analyses indicated that the DNA damage stimulus response and drug metabolism were important anti-fungi strategies of the whitefly. Mitogen-activated protein kinase (MAPK) pathway was also likely involved in the whitefly defense responses. Furthermore, the notable suppression of general metabolism and ion transport genes observed in 72 hours post-infected B. tabaci might be manipulated by fungal secreted effectors. By mapping the sequencing tags to B. bassiana genome, we also identified a number of differentially expressed fungal genes between the early and late infection stages. These genes are generally associated with fungal cell wall synthesis and energy metabolism. The expression of fungal cell wall protein genes might play an important role in fungal pathogenesis and the dramatically up-regulated enzymes of carbon metabolism indicate the increasing usage of energy during the fungal infection. Conclusions/Significance To our knowledge, this is the first report on the molecular mechanism of fungus-whitefly interactions. Our results provide a road map for future investigations on insect-pathogen interactions and

  10. Analysis of whitefly transcriptional responses to Beauveria bassiana infection reveals new insights into insect-fungus interactions.

    PubMed

    Xia, Jun; Zhang, Chang-Rong; Zhang, Shan; Li, Fang-Fang; Feng, Ming-Guang; Wang, Xiao-Wei; Liu, Shu-Sheng

    2013-01-01

    The fungal pathogen, Beauveria bassiana, is an efficient biocontrol agent against a variety of agricultural pests. A thorough understanding of the basic principles of insect-fungus interactions may enable the genetic modification of Beauveria bassiana to enhance its virulence. However, the molecular mechanism of insect response to Beauveria bassiana infection is poorly understood, let alone the identification of fungal virulent factors involved in pathogenesis. Here, next generation sequencing technology was applied to examine the expression of whitefly (Bemisia tabaci) genes in response to the infection of Beauveria bassiana. Results showed that, compared to control, 654 and 1,681genes were differentially expressed at 48 hours and 72 hours post-infected whiteflies, respectively. Functional and enrichment analyses indicated that the DNA damage stimulus response and drug metabolism were important anti-fungi strategies of the whitefly. Mitogen-activated protein kinase (MAPK) pathway was also likely involved in the whitefly defense responses. Furthermore, the notable suppression of general metabolism and ion transport genes observed in 72 hours post-infected B. tabaci might be manipulated by fungal secreted effectors. By mapping the sequencing tags to B. bassiana genome, we also identified a number of differentially expressed fungal genes between the early and late infection stages. These genes are generally associated with fungal cell wall synthesis and energy metabolism. The expression of fungal cell wall protein genes might play an important role in fungal pathogenesis and the dramatically up-regulated enzymes of carbon metabolism indicate the increasing usage of energy during the fungal infection. To our knowledge, this is the first report on the molecular mechanism of fungus-whitefly interactions. Our results provide a road map for future investigations on insect-pathogen interactions and genetically modifying the fungus to enhance its efficiency in whitefly

  11. Epidemiology and genetic diversity of criniviruses associated with tomato yellows disease in Greece.

    PubMed

    Orfanidou, C G; Dimitriou, C; Papayiannis, L C; Maliogka, V I; Katis, N I

    2014-06-24

    Tomato chlorosis virus (ToCV) and Tomato infectious chlorosis virus (TICV) are two whitefly transmitted viruses which are classified in the genus Crinivirus of the family Closteroviridae. Both induce similar yellowing symptoms in tomato and are responsible for severe economic losses. ToCV is transmitted by Bemisia tabaci Gennadious, Trialeurodes vaporariorum Westwood and Trialeurodes abutilonea Haldeman, whereas TICV is transmitted only by T. vaporariorum. An extensive study was conducted during 2009-2012 in order to identify the virus species involved in tomato yellowing disease in Greece. Samples from tomato, other crops and weeds belonging to 44 species from 26 families were collected and analyzed using molecular methods. In addition, adult whiteflies were collected and analyzed using morphological characters and DNA markers. Results showed that TICV prevailed in tomato crops (62.5%), while ToCV incidence was lower (20.5%) and confined in southern Greece. ToCV was also detected in lettuce plants showing mild yellowing symptoms for the first time in Greece. Approximately 13% of the tested weeds were found to be infected, with TICV being the predominant virus with an incidence of 10.8%, whereas ToCV was detected only in 2.2% of the analyzed samples. These results indicate that the host range of TICV and ToCV in Greece is far more extensive than previously believed. T. vaporariorum was the most widespread whitefly species in Greece (80%), followed by B. tabaci (biotypes B and Q) (20%). Sequence analysis of the CP and CPm genes from Greek tomato and weed isolates of ToCV and TICV showed that even though both viruses have very wide host ranges their populations show very low molecular divergence. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Knock down of Whitefly Gut Gene Expression and Mortality by Orally Delivered Gut Gene-Specific dsRNAs.

    PubMed

    Vyas, Meenal; Raza, Amir; Ali, Muhammad Yousaf; Ashraf, Muhammad Aleem; Mansoor, Shahid; Shahid, Ahmad Ali; Brown, Judith K

    2017-01-01

    Control of the whitefly Bemisia tabaci (Genn.) agricultural pest and plant virus vector relies on the use of chemical insecticides. RNA-interference (RNAi) is a homology-dependent innate immune response in eukaryotes, including insects, which results in degradation of the corresponding transcript following its recognition by a double-stranded RNA (dsRNA) that shares 100% sequence homology. In this study, six whitefly 'gut' genes were selected from an in silico-annotated transcriptome library constructed from the whitefly alimentary canal or 'gut' of the B biotype of B. tabaci, and tested for knock down efficacy, post-ingestion of dsRNAs that share 100% sequence homology to each respective gene target. Candidate genes were: Acetylcholine receptor subunit α, Alpha glucosidase 1, Aquaporin 1, Heat shock protein 70, Trehalase1, and Trehalose transporter1. The efficacy of RNAi knock down was further tested in a gene-specific functional bioassay, and mortality was recorded in 24 hr intervals, six days, post-treatment. Based on qPCR analysis, all six genes tested showed significantly reduced gene expression. Moderate-to-high whitefly mortality was associated with the down-regulation of osmoregulation, sugar metabolism and sugar transport-associated genes, demonstrating that whitefly survivability was linked with RNAi results. Silenced Acetylcholine receptor subunit α and Heat shock protein 70 genes showed an initial low whitefly mortality, however, following insecticide or high temperature treatments, respectively, significantly increased knockdown efficacy and death was observed, indicating enhanced post-knockdown sensitivity perhaps related to systemic silencing. The oral delivery of gut-specific dsRNAs, when combined with qPCR analysis of gene expression and a corresponding gene-specific bioassay that relates knockdown and mortality, offers a viable approach for functional genomics analysis and the discovery of prospective dsRNA biopesticide targets. The approach can

  13. RNA interference tools for the western flower thrips, Frankliniella occidentalis.

    PubMed

    Badillo-Vargas, Ismael E; Rotenberg, Dorith; Schneweis, Brandi A; Whitfield, Anna E

    2015-05-01

    The insect order Thysanoptera is exclusively comprised of small insects commonly known as thrips. The western flower thrips, Frankliniella occidentalis, is an economically important pest amongst thysanopterans due to extensive feeding damage and tospovirus transmission to hundreds of plant species worldwide. Geographically-distinct populations of F. occidentalis have developed resistance against many types of traditional chemical insecticides, and as such, management of thrips and tospoviruses are a persistent challenge in agriculture. Molecular methods for defining the role(s) of specific genes in thrips-tospovirus interactions and for assessing their potential as gene targets in thrips management strategies is currently lacking. The goal of this work was to develop an RNA interference (RNAi) tool that enables functional genomic assays and to evaluate RNAi for its potential as a biologically-based approach for controlling F. occidentalis. Using a microinjection system, we delivered double-stranded RNA (dsRNA) directly to the hemocoel of female thrips to target the vacuolar ATP synthase subunit B (V-ATPase-B) gene of F. occidentalis. Gene expression analysis using real-time quantitative reverse transcriptase-PCR (qRT-PCR) revealed significant reductions of V-ATPase-B transcripts at 2 and 3 days post-injection (dpi) with dsRNA of V-ATPase-B compared to injection with dsRNA of GFP. Furthermore, the effect of knockdown of the V-ATPase-B gene in females at these two time points was mirrored by the decreased abundance of V-ATPase-B protein as determined by quantitative analysis of Western blots. Reduction in V-ATPase-B expression in thrips resulted in increased female mortality and reduced fertility, i.e., number of viable offspring produced. Survivorship decreased significantly by six dpi compared to the dsRNA-GFP control group, which continued decreasing significantly until the end of the bioassay. Surviving female thrips injected with dsRNA-V-ATPase-B produced

  14. Soil sampling and extraction methods with possible application to pear thrips (Thysanoptera: Thripidae)

    Treesearch

    John E. Bater

    1991-01-01

    Techniques are described for the sampling and extraction of microarthropods from soil and the potential of these methods to extract the larval stages of the pear thrips, Taeniothrips inconsequens (Uzel), from soil cores taken in sugar maple stands. Also described is a design for an emergence trap that could be used to estimate adult thrips...

  15. Repellency of Plant Extracts against the Legume Flower Thrips Megalurothrips sjostedti (Thysanoptera: Thripidae)

    PubMed Central

    Abtew, Andnet; Subramanian, Sevgan; Cheseto, Xavier; Kreiter, Serge; Tropea Garzia, Giovanna; Martin, Thibaud

    2015-01-01

    Megalurothrips sjostedti Trybom is an important pest of cowpea (Vigna unguiculata L.) in Africa. To propose an alternative to chemical control, the repellency of 24 plant extracts was evaluated against adult female thrips of M. sjostedti in the laboratory. Plant extracts in ethanol were separately applied on a filter paper disk in a still air visual cue olfactometer. The results showed highly significant differences in repellency among extract type, concentration and their interactions. We classified the level of repellency into four categories as strong, good, moderate and weak or non- repellent based on hierarchical ascendant classification. We identified Piper nigrum, Cinnamomum zeylanicum, Cinnamomum cassia as strong repellents. Five extracts were classified as good, eight as moderate and the remaining eight extracts were weak or non-repellent. Repellency of the extracts increased with the concentration suggesting that the behavioral response of M. sjostedti was dose-dependent. Mono- and sesquiterpene hydrocarbon compounds from seven highly repellent extracts were identified by gas chromatography-mass spectrometry (GC/MS). The use of repellent extracts could be useful in developing integrated pest management strategies for thrips on legume crops. In this regard, the specific modes of action of the identified compounds need to be investigated to incorporate them into the existing crop protection strategies. PMID:26463406

  16. Temporal and spatial distribution of an invasive thrips species Scirtothrips dorsalis (Thysanoptera: Thripidae)

    USDA-ARS?s Scientific Manuscript database

    Dispersion of a new invasive thrips species, chilli thrips Scirtothrips dorsalis Hood, was studied on three hosts, i.e., cotton (Gossypium hirsutum L.), peanut (Arachis hypogeal L.) and pepper (Capsicum annum L.) in the greenhouse and under field conditions in Homestead, Florida. The study of horizo...

  17. Attraction of thrips (Thysanoptera) to colored sticky traps in a Florida olive grove

    USDA-ARS?s Scientific Manuscript database

    A study was conducted in four plots within a newly established olive grove in Florida to compare efficacy of colored sticky traps for surveillance of pests and to compare with other direct sampling methods. Over 99% of thrips collected were Frankliniella bispinosa with occasional collections of pred...

  18. Temperature stress effects in Bemisia tabaci (Hemiptera: Aleyrodidae) type B whiteflies

    USDA-ARS?s Scientific Manuscript database

    Oxidative stress occurs in response to changes in the redox equilibiurm, which may be caused by increases in reactive oxygen species (ROS), a decrease in antioxidant protection or failure of cells to repair oxidative damage. ROS are either free radicals, reactive molecules containing oxygen atoms or...

  19. Diversity of insect galls associated with coastal shrub vegetation in Rio de Janeiro, Brazil.

    PubMed

    Carvalho-Fernandes, Sheila P; Ascendino, Sharlene; Maia, Valéria C; Couri, Márcia S

    2016-09-01

    Surveys in the coastal sandy plains (restingas) of Rio de Janeiro have shown a great richness of galls. We investigated the galling insects in two preserved restingas areas of Rio de Janeiro state: Parque Estadual da Costa do Sol and Reserva Particular do Patrimônio Natural Fazenda Caruara. The collections were done each two months, from June 2011 to May 2012. We investigated 38 points during 45 minutes each per collection. The galls were taken to the laboratory for rearing the insects. A total number of 151 insect galls were found in 82 plant species distributed into 34 botanic families. Most of the galls occurred on leaves and the plant families with the highest richness of galls were Myrtaceae and Fabaceae. All the six insect orders with galling species were found in this survey, where Cecidomyiidae (Diptera) was the main galler group. Hymenoptera and Thysanoptera were found as parasitoids and inquilines in 29 galls. The richness of galls in the surveyed areas reveals the importance of restinga for the composition and diversity of gall-inducing insect fauna.

  20. Susceptibility of Dalotia coriaria (Kraatz) (Coleoptera: Staphylinidae) to Entomopathogenic Nematodes (Rhabditida: Heterorhabditidae and Steinernematidae)

    PubMed Central

    Tourtois, Joseph; Grieshop, Matthew J.

    2015-01-01

    Dalotia coriaria (Kraatz) (Coleoptera: Staphylinidae) and entomopathogenic nematodes (Rhabditida: Heterorhabditidae and Steinernematidae) are two soil-dwelling biological control agents used to manage western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) and fungus gnats Bradysis spp. (Diptera: Sciaridae) in glasshouses. Growers often use multiple natural enemies to achieve economic control, but knowledge of interactions among natural enemies is lacking. We conducted a laboratory bioassay to test the pathogenicity of four commercially available nematode species—Heterorhabditis bacteriophora Poinar (Rhabditida: Heterorhbditidae), Steinernema carpocapsae (Weiser) (Rhabditida: Steinernematidae), S. feltiae (Filipjev), and S. riobrave Cabanillas et al.—to third instar and adult D. coriaria. Third instars were three times more susceptible than the adults to the entomopathogenic nematodes. Mortality for D. coriaria adults and third instars treated with S. feltiae and H. bacteriophora was lower than the mortality for D. coriaria adults and third instars treated with S. carpocapsae and S. riobrave. Neither infective juvenile foraging behavior nor size correlates with D. coriaria mortality. Dalotia coriaria appears to be most likely compatible with applications of S. feltiae and H. bacteriophora. PMID:26463077

  1. The fine structure of the rectal pads of Zorotypus caudelli Karny (Zoraptera, Insecta).

    PubMed

    Dallai, R; Mercati, D; Mashimo, Y; Machida, R; Beutel, R G

    2016-07-01

    The rectal pads of a species of the controversial polyneopteran order Zoraptera were examined using histological sections and TEM micrographs. Six pads are present along the thin rectal epithelium. Each pad consists of a few large principal cells surrounded by flattened junctional cells, which extend also beneath the principal cells. The cells are lined by a thin apical cuticle. No basal cells and no cavity have been observed beneath the pad. Principal cells have a regular layer of apical microvilli and are joined by intercellular septate junctions, which are interrupted by short dilatations of the intercellular space. At these levels the two adjacent plasma membranes are joined by short zonulae adhaerentes. In the cytoplasm, a rich system of strict associations between lateral plasma membranes and mitochondria forms scalariform junctions. Rectal pads share ultrastructural features with similar excretory organs of several neopteran groups, in particular with Blattodea (roaches and termites) and Thysanoptera, and are involved in fluid reabsorption and ion regulation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Frankliniella occidentalis (Pergande) integrated pest management programs for fruiting vegetables in Florida.

    PubMed

    Demirozer, Ozan; Tyler-Julian, Kara; Funderburk, Joe; Leppla, Norm; Reitz, Stuart

    2012-12-01

    The spread of the western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), resulted in the worldwide destabilization of established integrated pest management programs for many crops. Efforts to control the pest and the thrips-vectored tospoviruses with calendar applications of broad-spectrum insecticides have been unsuccessful. The result has been a classic '3-R' situation: resistance to numerous insecticides; resurgence of the western flower thrips populations as a result of natural predators and native competitor thrips being eliminated; replacement by various other pests. This paper reports on integrated pest management programs for fruiting vegetables that are effective, economical, ecologically sound and sustainable. The components include the following: define pest status (economic thresholds); increase biotic resistance (natural enemies and competition); integrate preventive and therapeutic tactics (scouting, ultraviolet-reflective technologies, biological control, compatible insecticides, companion plants and fertility); vertically integrate the programs with other pests; continually communicate latest science-based management tactics with end-users. These programs have been widely implemented in Florida and have significantly improved the management of western flower thrips and thrips-transmitted viruses. Copyright © 2012 Society of Chemical Industry.

  3. The Scirtothrips perseae species-group (Thysanoptera), with one new species from avocado, Persea americana.

    PubMed

    Mound, Laurence A; Hoddle, Mark S

    2016-02-12

    Following recent molecular studies on avocado thrips, a new species is described from Costa Rica, Ecuador, and Colombia from the young leaves of avocado, Persea americana. Scirtothrips hansoni sp.n. is closely related to the Californian pest, S. perseae, and also to S. astrictus from Costa Rica that remains known from a single female. An illustrated key to these three species is provided.

  4. Thrips (Thysanoptera: Thripidae) mitigation in seedling cotton using strip tillage and winter cover crops.

    PubMed

    Toews, Michael D; Tubbs, R Scott; Wann, Dylan Q; Sullivan, Dana

    2010-10-01

    Thrips are the most consistent insect pests of seedling cotton in the southeastern United States, where symptoms can range from leaf curling to stand loss. In a 2 year study, thrips adults and immatures were sampled at 14, 21 and 28 days after planting on cotton planted with a thiamethoxam seed treatment in concert with crimson clover, wheat or rye winter cover crops and conventional or strip tillage to investigate potential differences in thrips infestations. Densities of adult thrips, primarily Frankliniella fusca (Hinds), peaked on the first sampling date, whereas immature densities peaked on the second sampling date. Regardless of winter cover crop, plots that received strip tillage experienced significantly fewer thrips at each sampling interval. In addition, assessment of percentage ground cover 42 days after planting showed that there was more than twice as much ground cover in the strip-tilled plots compared with conventionally tilled plots. Correlation analyses showed that increased ground cover was inversely related to thrips densities that occurred on all three sampling dates in 2008 and the final sampling date in 2009. Growers who utilize strip tillage and a winter cover crop can utilize seed treatments for mitigation of early-season thrips infestation.

  5. Studies on Dendrothripinae (Thysanoptera, Thripidae) from Japan, with new records and one new species.

    PubMed

    Masumoto, Masami; Okajima, Shûji

    2017-12-05

    Pseudodendrothrips maculatus sp.n. is described from Morus leaves in Japan, and the following five species of Dendrothripinae are newly recorded from Japan: Leucothrips furcatus Hood, L. nigripennis Reuter, L. piercei (Morgan), Pseudodendrothrips darci (Girault) and P. lateralis Wang. Moreover, P. bhattii is newly recorded from Taiwan. An identification key to Pseudodendrothrips species from Japan and Taiwan is provided, and the metathoracic pleural area is compared between several Dendrothripinae genera.

  6. Baseline Susceptibilities of B- and Q-biotype Bemisia tabaci to anthranilic diamides

    USDA-ARS?s Scientific Manuscript database

    Development of pyriproxyfen and neonicotinoid resistance in the B biotype whitefly and recent introduction of the Q biotype are threatening the current whitefly management programs in Arizona. Whether the novel anthranilic diamides chlorantraniliprole and cyantraniliprole can be integrated into the ...

  7. Comparing the regional epidemiology of the cassava mosaic and cassava brown streak virus pandemics in Africa.

    PubMed

    Legg, J P; Jeremiah, S C; Obiero, H M; Maruthi, M N; Ndyetabula, I; Okao-Okuja, G; Bouwmeester, H; Bigirimana, S; Tata-Hangy, W; Gashaka, G; Mkamilo, G; Alicai, T; Lava Kumar, P

    2011-08-01

    The rapid geographical expansion of the cassava mosaic disease (CMD) pandemic, caused by cassava mosaic geminiviruses, has devastated cassava crops in 12 countries of East and Central Africa since the late 1980s. Region-level surveys have revealed a continuing pattern of annual spread westward and southward along a contiguous 'front'. More recently, outbreaks of cassava brown streak disease (CBSD) were reported from Uganda and other parts of East Africa that had been hitherto unaffected by the disease. Recent survey data reveal several significant contrasts between the regional epidemiology of these two pandemics: (i) severe CMD radiates out from an initial centre of origin, whilst CBSD seems to be spreading from independent 'hot-spots'; (ii) the severe CMD pandemic has arisen from recombination and synergy between virus species, whilst the CBSD pandemic seems to be a 'new encounter' situation between host and pathogen; (iii) CMD pandemic spread has been tightly linked with the appearance of super-abundant Bemisia tabaci whitefly vector populations, in contrast to CBSD, where outbreaks have occurred 3-12 years after whitefly population increases; (iv) the CMGs causing CMD are transmitted in a persistent manner, whilst the two cassava brown streak viruses appear to be semi-persistently transmitted; and (v) different patterns of symptom expression mean that phytosanitary measures could be implemented easily for CMD but have limited effectiveness, whereas similar measures are difficult to apply for CBSD but are potentially very effective. An important similarity between the pandemics is that the viruses occurring in pandemic-affected areas are also found elsewhere, indicating that contrary to earlier published conclusions, the viruses per se are unlikely to be the key factors driving the two pandemics. A diagrammatic representation illustrates the temporal relationship between B. tabaci abundance and changing incidences of both CMD and CBSD in the Great Lakes region

  8. The Effect of Organic Fertilizers and Flowering Plants on Sheet-Web and Wolf Spider Populations (Araneae: Lycosidae and Linyphiidae) and Its Importance for Pest Control

    PubMed Central

    El-Nabawy, El-Said M.; Tsuda, Katsuo; Sakamaki, Yositaka; Oda, Asahi; Ushijima, Yurie

    2016-01-01

    The main goal of this study was to identify the treatment that increases the populations of spiders, which are effective predators in agroecosystems. In 2013 and 2014 the experimental eggplant (Solanum melongena L.) field was two different treatments, organic fertilizers and chemical fertilizer treatment, and in 2014 we surrounded organic fertilizer plots with the flowering plants mealy cup sage (Salvia farinacea Benth.), spearmint (Mentha spicata L.), and basil (Ocimum basilicum L.). Analysis using repeated measures ANOVA revealed significant influences of fertilizer type on the numbers of linyphiid spiders and Collembola in 2013. In 2014, the numbers of Collembola, thrips, and lycosid and linyphiid spider were higher in organic fertilizer with flowering plants treatment comparing with the chemical fertilizer treatment. Moreover, the numbers of Henosepilachna vigintioctopunctata (F.) were significantly lower in the organic fertilizer with flowering plants treatment than in chemical fertilizers treatment. Finally, we expect that Thysanoptera and Collembola were important alternative prey for linyphiid and lycosid spiders and the use of organic fertilizer and flowering plants enhanced the density of these spiders, and may increase their effectiveness in suppressing the populations of H. vigintioctopunctata (F.). PMID:28076280

  9. A decade of a thrips invasion in China: lessons learned.

    PubMed

    Wu, Shengyong; Tang, Liangde; Zhang, Xingrui; Xing, Zhenlong; Lei, Zhongren; Gao, Yulin

    2017-10-11

    The Western flower thrips, Frankliniella occidentalis Pergande (Thysanoptera: Thripidae) is an invasive polyphagous pest with an expanding global range that damages a wide variety of crops. F. occidentalis was first reported in China from Yunnan province during 2000, and has rapidly expanded its range since then. It is currently distributed across at least 10 provinces in China and has become a particularly devastating pest, causing substantial damage and economic losses. At present, the still heavy reliance on frequent use of insecticides for control of F. occidentalis, has lead to a series of ecological problems stemming from insecticide resistance, interspecific displacement and non-target effects. Thus, integrated pest management (IPM) programmes, multiple complementary tactics, including preventive tactics, biological controls, and judicious use of insecticides will likely provide a viable IPM strategy for control of F. occidentalis in the near future. This review provides an overview for information gained during the 10+ years since the invasion of F. occidentalis into China, reviews lessons that have been learned enhancing our overall understanding of the biology and ecology of F. occidentalis and discusses IPM practices relative to this widespread invasive insect pest.

  10. Thrips advisor: exploiting thrips-induced defences to combat pests on crops.

    PubMed

    Steenbergen, Merel; Abd-El-Haliem, Ahmed; Bleeker, Petra; Dicke, Marcel; Escobar-Bravo, Rocio; Cheng, Gang; Haring, Michel A; Kant, Merijn R; Kappers, Iris; Klinkhamer, Peter G L; Leiss, Kirsten A; Legarrea, Saioa; Macel, Mirka; Mouden, Sanae; Pieterse, Corné M J; Sarde, Sandeep J; Schuurink, Robert C; De Vos, Martin; Van Wees, Saskia C M; Broekgaarden, Colette

    2018-04-09

    Plants have developed diverse defence mechanisms to ward off herbivorous pests. However, agriculture still faces estimated crop yield losses ranging from 25% to 40% annually. These losses arise not only because of direct feeding damage, but also because many pests serve as vectors of plant viruses. Herbivorous thrips (Thysanoptera) are important pests of vegetable and ornamental crops worldwide, and encompass virtually all general problems of pests: they are highly polyphagous, hard to control because of their complex lifestyle, and they are vectors of destructive viruses. Currently, control management of thrips mainly relies on the use of chemical pesticides. However, thrips rapidly develop resistance to these pesticides. With the rising demand for more sustainable, safer, and healthier food production systems, we urgently need to pinpoint the gaps in knowledge of plant defences against thrips to enable the future development of novel control methods. In this review, we summarize the current, rather scarce, knowledge of thrips-induced plant responses and the role of phytohormonal signalling and chemical defences in these responses. We describe concrete opportunities for breeding resistance against pests such as thrips as a prototype approach for next-generation resistance breeding.

  11. The Green Lacewing, Chrysoperla carnea: Preference between Lettuce Aphids, Nasonovia ribisnigri, and Western Flower Thrips, Frankliniella occidentalis

    PubMed Central

    Shrestha, Govinda; Enkegaard, Annie

    2013-01-01

    This study investigated the prey preference of 3rd instar green lacewing, Chrysoperla carnea Stephens (Neuroptera: Chrysopidae), between western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), and lettuce aphids, Nasonovia ribisnigri (Mosley) (Hemiptera: Aphididae) in laboratory experiments at 25 ± 1° C and 70 ± 5% RH with five prey ratios (10 aphids:80 thrips, 25 aphids:65 thrips, 45 aphids:45 thrips, 65 aphids:25 thrips, and 80 aphids:10 thrips). Third instar C. carnea larvae readily preyed upon both thrips and aphids, with thrips mortality varying between 40 and 90%, and aphid mortality between 52 and 98%. Chrysoperla carnea had a significant preference for N. ribisnigri at two ratios (10 aphids:80 thrips, 65 aphids:25 thrips), but no preference for either prey at the other ratios. There was no significant linear relationship between preference index and prey ratio, but a significant intercept of the linear regression indicated an overall preference of C. carnea for aphids with a value of 0.651 ± 0.054. The possible implications of these findings for control of N. ribisnigri and F. occidentalis by C. carnea are discussed. PMID:24205864

  12. The green lacewing, Chrysoperla carnea: preference between lettuce aphids, Nasonovia ribisnigri, and Western flower thrips, Frankliniella occidentalis.

    PubMed

    Shrestha, Govinda; Enkegaard, Annie

    2013-01-01

    This study investigated the prey preference of 3(rd) instar green lacewing, Chrysoperla carnea Stephens (Neuroptera: Chrysopidae), between western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), and lettuce aphids, Nasonovia ribisnigri (Mosley) (Hemiptera: Aphididae) in laboratory experiments at 25 ± 1° C and 70 ± 5% RH with five prey ratios (10 aphids:80 thrips, 25 aphids:65 thrips, 45 aphids:45 thrips, 65 aphids:25 thrips, and 80 aphids:10 thrips). Third instar C. carnea larvae readily preyed upon both thrips and aphids, with thrips mortality varying between 40 and 90%, and aphid mortality between 52 and 98%. Chrysoperla carnea had a significant preference for N. ribisnigri at two ratios (10 aphids:80 thrips, 65 aphids:25 thrips), but no preference for either prey at the other ratios. There was no significant linear relationship between preference index and prey ratio, but a significant intercept of the linear regression indicated an overall preference of C. carnea for aphids with a value of 0.651 ± 0.054. The possible implications of these findings for control of N. ribisnigri and F. occidentalis by C. carnea are discussed.

  13. Behavioural responses of Frankliniella occidentalis Pergande larvae to methyl jasmonate and cis-jasmone.

    PubMed

    Egger, Barbara; Koschier, Elisabeth H

    2014-01-01

    The larval stages of Frankliniella occidentalis Pergande (Thysanoptera: Thripidae) cause more direct feeding damage to plants than the adults. We, therefore, investigated the behaviour-modifying effects on second instar larvae of two jasmonic acid derivatives. The artificial application of methyl jasmonate and cis -jasmone, both at 1 % concentration, deterred the larvae from settling in a dual choice bean leaf disc assay. We observed a dose-dependent feeding deterrence of both jasmonates and calculated the concentration required to reduce the feeding damage by 50 % relative to the control treatment (FDC 50 ) for each jasmonate. The feeding damage was reduced by the application of cis -jasmone at 1 % concentration, but not by the jasmonates at the respective FDC 50 in no-choice leaf disc bioassays. However, significantly more larvae left jasmonate-treated whole potted bean plants by migrating to the soil compared with control plants. Our results may be exploited extending behavioural manipulation by using plant compounds in thrips control programmes to the full lifecycle of the pest. Plant compounds could be used in integrated and biological pest management strategies against F. occidentalis in combination with the application of various above and below ground control measures.

  14. Insects galls of Pantanal areas in the State of Mato Grosso do Sul, Brazil: characterization and occurrence.

    PubMed

    Ascendino, Sharlene; Maia, Valéria C

    2018-01-01

    Two Pantanal areas were investigated in Corumbá, Mato Grosso do Sul. The field works were carried out in five trails, in August and December/2011 and April/2012. Seventy-six gall morphotypes were found in 52 host plants, 22 of them were identified at species level and 30 at genus. Fabaceae, Myrtaceae and Sapindaceae were the plant families with the greatest richness of gall. Leaves were the plant organ with the greatest gall richness. Six gall shapes were found - globoid, lenticular, fusiform, cylindrical, conical, and marginal roll. The three first were the most common. Five colors were observed - green, brown, red, yellow, and black. Green and brown predominated. Most were glabrous and one-chambered. These features have been indicated in several Brazilian biomes. Diptera (Cecidomyiidae) were the most frequent gallers. The associated fauna comprised parasitoids (Eulophidae, Braconidae, Eupelmidae, Eurytomidae, Platygastridae, and Pteromalidae), inquilines (Cecidomyiidae: Trotteria Kieffer, 1902, Hymenoptera: Tanaostigmoides Ashmead, 1896, Hemiptera, Lepidoptera and Thysanoptera) and predators (Pseudoscorpionida: Olpiolum medium Beier, 1931, Cecidomyiidae: Lestodiplosini and Hymenoptera: Formicidae). Parasitoids were the most frequent. Multiparatism was observed. Our data represent the first contribution to the knowledge of the associated fauna in the Pantanal.

  15. Two new species of Scirtothrips genus-group (Thripidae) of Northern Peninsular Malaysia.

    PubMed

    Ng, Y F; Mound, L A

    2016-03-07

    The survey of Thysanoptera in peninsular Malaysia has been concentrated largely in areas growing crops and flowers around Kuala Lumpur, and the Cameron Highlands, and there are few records of these insects from native forests particularly in the northern part of the country. The two species described here were collected during a recent visit to Belum-Temengor Forest Complex, in Perak State, part of the second largest forested area on the peninsular, and connected to the Bang Lang National Park, in Yala Province, Thailand. This forest has been well known as home to a number of endangered animals, including Malayan tigers and Asian elephants, as well as remarkable plant species such as Rafflesia with the world's largest flowers (Abdullah et al. 2011). Despite this, forest areas are facing a major challenge from the insatiable demand for timber, palm oil and minerals, with an 80% increase in deforestation rate in Malaysia between 1990 and 2005 (FAO 2010). Forested land in peninsular Malaysia has been estimated at 5.88 million-ha or 44% of total area, but the coverage of reserved virgin forest is about 0.40 % or 23,002-ha (Dahlan 2008).

  16. Minute pollinators: The role of thrips (Thysanoptera) as pollinators of pointleaf manzanita, Arctostaphylos pungens (Ericaceae)

    PubMed Central

    Eliyahu, Dorit; McCall, Andrew C.; Lauck, Marina; Trakhtenbrot, Ana; Bronstein, Judith L.

    2015-01-01

    The feeding habits of thrips on plant tissue, and their ability to transmit viral diseases to their host plants, have usually placed these insects in the general category of pests. However, the characteristics that make them economically important, their high abundance and short- and long-distance movement capability, may also make them effective pollinators. We investigated this lesser-known role of thrips in pointleaf manzanita (Arctostaphylos pungens), a Southwestern US shrub. We measured the abundance of three species of thrips (Orothrips kelloggii, Oligothrips oreios, and Frankliniella occidentalis), examined their pollen-carrying capability, and conducted an exclusion experiment in order to determine whether thrips are able to pollinate this species, and if they do, whether they actually contribute to the reproductive success of the plant. Our data suggest that indeed thrips pollinate and do contribute significantly to reproductive success. Flowers exposed to thrips only produced significantly more fruit than did flowers from which all visitors were excluded. The roles of thrips as antagonists/mutualists are examined in the context of the numerous other floral visitors to the plant. PMID:26207155

  17. Development of sampling methods for the slash pine flower thrips Gnophothrips fuscus (Morgan), (Thysanoptera: Phlaeothripidae)

    Treesearch

    Carl W. Fatzinger; Wayne N. Dixen

    1991-01-01

    Slash pine flower thrips typically destroy about 24% of the flowers (cones) present in slash pine seed orchards. The seasonal distribution and abundance of slash pine flower thrips are being investigated and methods for sampling field populations of the insect are being evaluated for potential use in integrated pest management strategies. The efficacies of several...

  18. Minute pollinators: The role of thrips (Thysanoptera) as pollinators of pointleaf manzanita, Arctostaphylos pungens (Ericaceae).

    PubMed

    Eliyahu, Dorit; McCall, Andrew C; Lauck, Marina; Trakhtenbrot, Ana; Bronstein, Judith L

    The feeding habits of thrips on plant tissue, and their ability to transmit viral diseases to their host plants, have usually placed these insects in the general category of pests. However, the characteristics that make them economically important, their high abundance and short- and long-distance movement capability, may also make them effective pollinators. We investigated this lesser-known role of thrips in pointleaf manzanita ( Arctostaphylos pungens ), a Southwestern US shrub. We measured the abundance of three species of thrips ( Orothrips kelloggii, Oligothrips oreios , and Frankliniella occidentalis ), examined their pollen-carrying capability, and conducted an exclusion experiment in order to determine whether thrips are able to pollinate this species, and if they do, whether they actually contribute to the reproductive success of the plant. Our data suggest that indeed thrips pollinate and do contribute significantly to reproductive success. Flowers exposed to thrips only produced significantly more fruit than did flowers from which all visitors were excluded. The roles of thrips as antagonists/mutualists are examined in the context of the numerous other floral visitors to the plant.

  19. Comparison of life history parameters of two Frankliniella occidentalis (Thysanoptera: Thripidae) strains in New Zealand.

    PubMed

    Nielsen, M-C; Teulon, D A J; Chapman, R B; Butler, R C; Drayton, G M; Philipsen, H

    2010-04-01

    Two strains of western flower thrips, Frankliniella occidentalis (Pergande), are reputedly found in New Zealand. One strain was recorded in 1934, and it is most common in flowers of Lupinus arboreus outdoors (lupin strain); the other strain was first recorded in New Zealand in 1992 and is found mostly indoors on greenhouse crops (greenhouse strain). Laboratory studies were conducted to compare the life history parameters of these two strains. Thrips from each strain were fed sucrose solution and capsicum or lupin pollen and reared at 25 degrees C, >60% RH, and 16 L:8 D photoperiod. Significant differences in life history parameters were found. Preoviposition time was significantly shorter, and oviposition rate and fecundity were markedly higher (four-fold) for the greenhouse than for the lupin strain. The lupin strain performed significantly better on the capsicum pollen, laying more than twice as many eggs than on the lupin pollen over a 14-d period. The greenhouse strain development time from larvae to adult was marginally faster (0.7-1.1 d less) than the lupin strain because of a shorter prepupal and a marginally shorter pupal development time. Females of the greenhouse strain lived on average 69% longer than females from the lupin strain. Large differences in the intrinsic growth rate (r(m)) were found, with r(m) being 1.4-1.8 times higher for the greenhouse strain than the lupin strain, depending on pollen source. The results are discussed in relation to different ecological requirements and pest status of the two strains.

  20. Compatibility of spinosad with predaceous mites (Acari) used to control Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae).

    PubMed

    Rahman, Touhidur; Spafford, Helen; Broughton, Sonya

    2011-08-01

    Spinosad is a biopesticide widely used for control of Frankliniella occidentalis (Pergande). It is reported to be non-toxic to several predatory mite species used for the biological control of thrips. Predatory mites Typhlodromips montdorensis (Schicha), Neoseiulus cucumeris (Oudemans) and Hypoaspis miles (Berlese) have been used for control of F. occidentalis. This study investigated the impact of direct and residual toxicity of spinosad on F. occidentalis and predatory mites. The repellency of spinosad residues to these predatory mites was also investigated. Direct contact to spinosad effectively reduced the number of F. occidentalis adults and larvae, causing > 96% mortality. Spinosad residues aged 2-96 h were also toxic to F. occidentalis. Direct exposure to spinosad resulted in > 90% mortality of all three mite species. Thresholds for the residual toxicity (contact) of spinosad (LT25 ) were estimated as 4.2, 3.2 and 5.8 days for T. montdorensis, N. cucumeris and H. miles respectively. When mites were simultaneously exposed to spinosad residues and fed spinosad-intoxicated thrips larvae, toxicity increased. Residual thresholds were re-estimated as 5.4, 3.9 and 6.1 days for T. montdorensis, N. cucumeris and H. miles respectively. Residues aged 2-48 h repelled T. montdorensis and H. miles, and residues aged 2-24 h repelled N. cucumeris. Predatory mites can be safely released 6 days after spinosad is applied for the management of F. occidentalis. Copyright © 2011 Society of Chemical Industry.

  1. Fungus-feeding Thysanoptera: Phlaeothripinae of the Idiothrips genus-group in Australia, with nine new species.

    PubMed

    Mound, Laurence A; Tree, Desley J

    2015-10-29

    In a group of fungus-feeding Phlaeothripinae characterized by complex body sculpture, identification keys are provided to three genera and 15 species from Australia, including nine new species. In the genus Azaleothrips one new species is described, and one Asian species is newly recorded from Australia. The genus Stictothrips is recorded from Australia for the first time, with two new species. Within the genus Strepterothrips considerable structural diversity is recorded including three new species in which antennal segment III is greatly reduced and bears no sense cones. Some species in this genus exhibit the unusual condition of having several setae on the pelta, the first abdominal tergite. Problems in the production of generic diagnoses within the Phlaeothripinae are discussed.

  2. The Role of Bacterial Chaperones in the Circulative Transmission of Plant Viruses by Insect Vectors

    PubMed Central

    Kliot, Adi; Ghanim, Murad

    2013-01-01

    Persistent circulative transmission of plant viruses involves complex interactions between the transmitted virus and its insect vector. Several studies have shown that insect vector proteins are involved in the passage and the transmission of the virus. Interestingly, proteins expressed by bacterial endosymbionts that reside in the insect vector, were also shown to influence the transmission of these viruses. Thus far, the transmission of two plant viruses that belong to different virus genera was shown to be facilitated by a bacterial chaperone protein called GroEL. This protein was shown to be implicated in the transmission of Potato leafroll virus (PLRV) by the green peach aphid Myzus persicae, and the transmission of Tomato yellow leaf curl virus (TYLCV) by the sweetpotato whitefly Bemisia tabaci. These tri-trophic levels of interactions and their possible evolutionary implications are reviewed. PMID:23783810

  3. Evaluation of mustard plants and other products to control sweetpotato whitefly, Bemisia tabaci

    USDA-ARS?s Scientific Manuscript database

    A major insect pest of vegetables and horticultural crops in the southeast US is the sweetpotato whitefly.Scientists at the USDA-Agriculture Research Service, Center for Veterinary Entomology, Gainesaville, Florida, evaluated the effect of giant red mustard plants and commercial products to control ...

  4. Investigating the Q invasion of Bemisia tabaci in Florida: Current status and update

    USDA-ARS?s Scientific Manuscript database

    Three separate Q haplotypes within Florida were discovered that could be used to associate populations known to be related by grower and plant type thereby tracking distribution routes. We determined that biotype Q entered Florida through at least two separate introductions. In-depth analysis of ins...

  5. Quantifying conservation biological control for management of Bemisia tabaci (Hemiptera: Aleyrodidae) in cotton

    USDA-ARS?s Scientific Manuscript database

    Conservation biological control can be an effective tactic for minimizing insect-induced damage to agricultural production. The most effective manner of applying CBC is through an Integrated Pest Management (IPM) strategy, combining many tactics including cultural controls, pest sampling, the use of...

  6. Gene-for-gene disease resistance: bridging insect pest and pathogen defense.

    PubMed

    Kaloshian, Isgouhi

    2004-12-01

    Active plant defense, also known as gene-for-gene resistance, is triggered when a plant resistance (R) gene recognizes the intrusion of a specific insect pest or pathogen. Activation of plant defense includes an array of physiological and transcriptional reprogramming. During the past decade, a large number of plant R genes that confer resistance to diverse group of pathogens have been cloned from a number of plant species. Based on predicted protein structures, these genes are classified into a small number of groups, indicating that structurally related R genes recognize phylogenetically distinct pathogens. An extreme example is the tomato Mi-1 gene, which confers resistance to potato aphid (Macrosiphum euphorbiae), whitefly (Bemisia tabaci), and root-knot nematodes (Meloidogyne spp.). While Mi-1 remains the only cloned insect R gene, there is evidence that gene-for-gene type of plant defense against piercing-sucking insects exists in a number of plant species.

  7. Pest and disease resistance enhanced by heterologous suppression of a Nicotiana plumbaginifolia cytochrome P450 gene CYP72A2.

    PubMed

    Smigocki, Ann C; Wilson, Dennis

    2004-12-01

    The functional role of the Nicotiana plumbaginifolia cytochrome P450 gene CYP72A2 was investigated in transgenic plants. N. tabacum plants transformed with a sense or antisense CYP72A2 construct exhibited diminished heights, branched stems, smaller leaves and deformed flowers. Western blot analysis revealed reduced levels of a 58 kDa protein corresponding to CYP72A2, suggesting that the CYP72A2 homolog was suppressed in the sense and antisense plants. Transgenic plants had increased resistance to Manduca sexta larvae that consumed about 35 to 90 less of transgenic versus control leaves. A virulent strain of Pseudomonas syringae pv. tabaci induced a disease-limiting response followed by a delayed and decreased development of disease symptoms in the transgenics. CYP72A2 gene mediated resistance suggests that the plant-pest or -pathogen interactions may have been modified by changes in bioactive metabolite pools.

  8. The anatomy of the thrips Heliothrips haemorrhoidalis (Thysanoptera, Thripidae) and its specific features caused by miniaturization.

    PubMed

    Polilov, Alexey A; Shmakov, Alexey S

    2016-09-01

    A new set of data on the internal and external structure of the adult and larva of the thrips Heliothrips haemorrhoidalis (Bouché, 1833) is presented. The structure of the internal systems of this thrips was revealed using modern methods of 3D computer modelling. The changes in shape and relative size are discussed as an outcome of miniaturization in comparison to the supposed ancestor of this species. The layout of the internal systems of thrips is compared to those of other insects similar in size: beetles of the families Ptiliidae and Corylophidae and wasps of the families Mymaridae and Trichogrammatidae. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Evaluation of yellow sticky traps for monitoring the population of thrips (Thysanoptera) in a mango orchard.

    PubMed

    Aliakbarpour, Hamaseh; Rawi, Che Salmah Md

    2011-08-01

    Populations of several thrips species were estimated using yellow sticky traps in an orchard planted with mango, Mangifera indica L. during the dry and wet seasons beginning in late 2008-2009 on Penang Island, Malaysia. To determine the efficacy of using sticky traps to monitor thrips populations, we compared weekly population estimates on yellow sticky traps with thrips population sizes that were determined (using a CO(2) method) directly from mango panicles. Dispersal distance and direction of thrips movement out of the orchard also were studied using yellow sticky traps placed at three distances from the edge of the orchard in four cardinal directions facing into the orchard. The number of thrips associated with the mango panicles was found to be correlated with the number of thrips collected using the sticky trap method. The number of thrips captured by the traps decreased with increasing distance from the mango orchard in all directions. Density of thrips leaving the orchard was related to the surrounding vegetation. Our results demonstrate that sticky traps have the potential to satisfactorily estimate thrips populations in mango orchards and thus they can be effectively employed as a useful tactic for sampling thrips.

  10. Biology, behavior and management of chilli thrips, and other invasive thrips (Thysanoptera: Thripidae) in south Florida

    USDA-ARS?s Scientific Manuscript database

    The rich vegetation and Neotropical climate of Florida make the state suitable for the invasion and establishment of exotic flora and fauna. In the past two decades, there are multiple thrips species which have invaded Florida and are considered serious pests owing to the economic or aesthetic damag...

  11. Life History Characteristics of Frankliniella occidentalis and Frankliniella intonsa (Thysanoptera: Thripidae) in Constant and Fluctuating Temperatures.

    PubMed

    Ullah, Mohammad Shaef; Lim, Un Taek

    2015-06-01

    Frankliniella occidentalis (Pergande) and Frankliniella intonsa (Trybom) are sympatric pests of many greenhouse and field crops in Korea. We compared the influence of constant (27.3°C) and fluctuating temperatures (23.8-31.5°C, with an average of 27.3°C) on the life table characteristics of F. occidentalis and F. intonsa held at a photoperiod of 16:8 (L:D) h and 45±5% relative humidity. The development times of both F. occidentalis and F. intonsa were significantly affected by temperature fluctuation, species, and sex. The development time from egg to adult of F. intonsa was shorter than that for F. occidentalis at both constant and fluctuating temperatures. Survival of immature life stages was higher under fluctuating than constant temperature for both thrips species. The total and daily production of first instars was higher in F. intonsa (90.4 and 4.2 at constant temperature, and 95.7 and 3.9 at fluctuating temperatures) than that of F. occidentalis (58.7 and 3.3 at constant temperature, and 60.5 and 3.1 at fluctuating temperatures) under both constant and fluctuating temperatures. The percentage of female offspring was greater in F. intonsa (72.1-75.7%) than in F. occidentalis (57.4-58.7%) under both temperature regimes. The intrinsic rate of natural increase (rm) was higher at constant temperature than at fluctuating temperature for both thrips species. F. intonsa had a higher rm value (0.2146 and 0.2004) than did F. occidentalis (0.1808 and 0.1733), under both constant and fluctuating temperatures, respectively. The biological response of F. occidentalis and F. intonsa to constant and fluctuating temperature was found to be interspecifically different, and F. intonsa may have higher pest potential than F. occidentalis based on the life table parameters we are reporting first here. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  12. Population abundance of Frankliniella occidentalis (Thysanoptera: Thripidae) and natural enemies on plant hosts in central Chile.

    PubMed

    Ripa, Renato; Funderburk, Joe; Rodriguez, Fernando; Espinoza, Fernanda; Mound, Laurence

    2009-04-01

    Populations of the invasive Frankliniella occidentalis (Pergande) are serious pests of agricultural crops in the Aconcagua Valley of central Chile. An extensive survey was conducted of 55 plant species in 24 families to identify plant hosts of F. occidentalis and to determine its relative abundance on each host during each season. A more intensive study was conducted on selected plant species serving as reproductive hosts to determine the population dynamics of F. occidentalis and to evaluate the potential importance of Orius species and other natural enemies for controlling F. occidentalis. Adults of F. occidentalis were active during each season of the year inhabiting the flowers of 91% of the sampled plant species in 22 families, and 86% of these plant species in 19 families served as reproductive hosts. The number of host plant species used was greatest in the spring and least in the winter. All of the hosts except Medicago sativa L. were used only when flowering. Populations of F. occidentalis were significantly aggregated in M. sativa in the terminal buds over the leaves when the host was not flowering, and in the flowers, followed by the terminal buds, followed by the leaves when the host was flowering. Larvae were 1.3-2.3 times more abundant on dates when M. sativa was flowering. There were no identifiable patterns in plant hosts based on endemicity or plant family. Most of the plant species used by F. occidentalis were inferior quality hosts where populations either declined or were stable. Populations of F. occidentalis on low-quality hosts generally escaped predation by Orius species and competition by other species of thrips. Only 25% of the food hosts and 28% of the reproductive hosts for F. occidentalis in the extensive survey, respectively, were host plants for Orius. Parasitoids and other predators were not found to be important in suppressing thrips on any of the plant hosts. Populations of F. occidentalis increased on only a few hosts, including M. sativa and Sisymbrium officinale L. Scop. These apparently are major sources of F. occidentalis adults invading crops. We conclude that F. occidentalis is established in central Chile and that it has replaced and possibly displaced the native Frankliniella australis (Morgan) as the most common thrips species.

  13. Biotic resistance limits the invasiveness of the western flower thrips, Frankliniella occidentalis (Thysanoptera: Thripidae), in Florida.

    PubMed

    Funderburk, Joe; Frantz, Galen; Mellinger, Charles; Tyler-Julian, Kara; Srivastava, Mrittunjai

    2016-04-01

    The spread of the western flower thrips, Frankliniella occidentalis (Pergande), has resulted in the world-wide destabilization of established integrated pest management programs for many crops. It is hypothesized that frequent exposure to insecticides in intensive agriculture selected for resistant populations, which allowed invasive populations in the eastern USA to overcome biotic resistance from the native community of species. Research conducted in Florida to understand the role of biotic factors in limiting the abundance of the western flower thrips is reviewed. Orius spp. (Hemiptera: Anthocoridae) are effective predators that suppress populations of thrips on crop and non-crop hosts in southern and northern Florida. Orius are more effective predators of the western flower thrips than the native flower thrips, F. tritici (Fitch) and F. bispinosa (Morgan). The native species are competitors of the western flower thrips. Excessive fertilization and the use of broad-spectrum insecticides in crop fields further enhances populations of the western flower thrips. Interactions with native species clearly limit the abundance of western flower thrips in Florida, but populations are abundant in fertilized crop fields where application of insecticides excludes predators and competitor species. © 2015 Institute of Zoology, Chinese Academy of Sciences.

  14. Evaluation and Validation of Reference Genes for qRT-PCR Normalization in Frankliniella occidentalis (Thysanoptera:Thripidae)

    PubMed Central

    Zheng, Yu-Tao; Li, Hong-Bo; Lu, Ming-Xing; Du, Yu-Zhou

    2014-01-01

    Quantitative real time PCR (qRT-PCR) has emerged as a reliable and reproducible technique for studying gene expression analysis. For accurate results, the normalization of data with reference genes is particularly essential. Once the transcriptome sequencing of Frankliniella occidentalis was completed, numerous unigenes were identified and annotated. Unfortunately, there are no studies on the stability of reference genes used in F. occidentalis. In this work, seven candidate reference genes, including actin, 18S rRNA, H3, tubulin, GAPDH, EF-1 and RPL32, were evaluated for their suitability as normalization genes under different experimental conditions using the statistical software programs BestKeeper, geNorm, Normfinder and the comparative ΔCt method. Because the rankings of the reference genes provided by each of the four programs were different, we chose a user-friendly web-based comprehensive tool RefFinder to get the final ranking. The result demonstrated that EF-1 and RPL32 displayed the most stable expression in different developmental stages; RPL32 and GAPDH showed the most stable expression at high temperatures, while 18S and EF-1 exhibited the most stable expression at low temperatures. In this study, we validated the suitable reference genes in F. occidentalis for gene expression profiling under different experimental conditions. The choice of internal standard is very important in the normalization of the target gene expression levels, thus validating and selecting the best genes will help improve the quality of gene expression data of F. occidentalis. What is more, these validated reference genes could serve as the basis for the selection of candidate reference genes in other insects. PMID:25356721

  15. Evaluation and validation of reference genes for qRT-PCR normalization in Frankliniella occidentalis (Thysanoptera: Thripidae).

    PubMed

    Zheng, Yu-Tao; Li, Hong-Bo; Lu, Ming-Xing; Du, Yu-Zhou

    2014-01-01

    Quantitative real time PCR (qRT-PCR) has emerged as a reliable and reproducible technique for studying gene expression analysis. For accurate results, the normalization of data with reference genes is particularly essential. Once the transcriptome sequencing of Frankliniella occidentalis was completed, numerous unigenes were identified and annotated. Unfortunately, there are no studies on the stability of reference genes used in F. occidentalis. In this work, seven candidate reference genes, including actin, 18S rRNA, H3, tubulin, GAPDH, EF-1 and RPL32, were evaluated for their suitability as normalization genes under different experimental conditions using the statistical software programs BestKeeper, geNorm, Normfinder and the comparative ΔCt method. Because the rankings of the reference genes provided by each of the four programs were different, we chose a user-friendly web-based comprehensive tool RefFinder to get the final ranking. The result demonstrated that EF-1 and RPL32 displayed the most stable expression in different developmental stages; RPL32 and GAPDH showed the most stable expression at high temperatures, while 18S and EF-1 exhibited the most stable expression at low temperatures. In this study, we validated the suitable reference genes in F. occidentalis for gene expression profiling under different experimental conditions. The choice of internal standard is very important in the normalization of the target gene expression levels, thus validating and selecting the best genes will help improve the quality of gene expression data of F. occidentalis. What is more, these validated reference genes could serve as the basis for the selection of candidate reference genes in other insects.

  16. New generic synonyms in the Palaeotropical genus Urothrips (Thysanoptera: Phlaeothripinae) with one new species from Seychelles.

    PubMed

    Ulitzka, Manfred R; Mound, Laurence A

    2014-01-28

    Urothrips kobroi sp. n. is described from Seychelles, and reasons are given for considering Biconothrips Stannard and Coxothrips Bournier as new synonyms of Urothrips Bagnall. This genus now includes nine species, distributed between Africa and Australia, and a key to these species is provided.

  17. The Effect of Organic Fertilizers and Flowering Plants on Sheet-Web and Wolf Spider Populations (Araneae: Lycosidae and Linyphiidae) and Its Importance for Pest Control.

    PubMed

    El-Nabawy, El-Said M; Tsuda, Katsuo; Sakamaki, Yositaka; Oda, Asahi; Ushijima, Yurie

    2016-01-01

    The main goal of this study was to identify the treatment that increases the populations of spiders, which are effective predators in agroecosystems. In 2013 and 2014 the experimental eggplant (Solanum melongena L.) field was two different treatments, organic fertilizers and chemical fertilizer treatment, and in 2014 we surrounded organic fertilizer plots with the flowering plants mealy cup sage (Salvia farinacea Benth.), spearmint (Mentha spicata L.), and basil (Ocimum basilicum L.). Analysis using repeated measures ANOVA revealed significant influences of fertilizer type on the numbers of linyphiid spiders and Collembola in 2013. In 2014, the numbers of Collembola, thrips, and lycosid and linyphiid spider were higher in organic fertilizer with flowering plants treatment comparing with the chemical fertilizer treatment. Moreover, the numbers of Henosepilachna vigintioctopunctata (F.) were significantly lower in the organic fertilizer with flowering plants treatment than in chemical fertilizers treatment. Finally, we expect that Thysanoptera and Collembola were important alternative prey for linyphiid and lycosid spiders and the use of organic fertilizer and flowering plants enhanced the density of these spiders, and may increase their effectiveness in suppressing the populations of H. vigintioctopunctata (F.). © The Author 2016. Published by Oxford University Press on behalf of the Entomological Society of America.

  18. Occurrence of Entomopathogenic Fungi from Agricultural and Natural Ecosystems in Saltillo, México, and their Virulence Towards Thrips and Whiteflies

    PubMed Central

    Sánchez-Peña, Sergio R.; Lara, Jorge San-Juan; Medina, Raúl F.

    2011-01-01

    Entomopathogenic fungi were collected from soil in four adjacent habitats (oak forest, agricultural soil, pine reforestation and chaparral habitat) in Saltillo, México using the insect bait method with Tenebrio molitor (L.) (Coleoptera: Tenebrionidae) larvae as bait. Overall, of the larvae exposed to soil, 171 (20%) hosted Beauveria bassiana (Balsamo) Vuillemin (Hypocreales: Cordycipitaceae), 25 (3%) hosted Metarhizium anisopliae (Metschnikoff) Sorokin (Hypocreales: Clavicipitaceae) and 1 (0.1%) hosted lsaria (=Paecilomyces) sp. (Hypocreales: Cordycipitaceae). B. bassiana was significantly more frequent on larvae exposed to oak forest soil. M. anisopliae was significantly more frequent on larvae exposed to agricultural soil. From the infected bait insects, 93 isolates of B. bassiana and 24 isolates of M. anisopliae were obtained. Strains were tested for their infectivity against Cuban laurel thrips, Gynaikothrips uzeli Zimmerman (Thysanoptera: Phlaeothripidae) and the greenhouse whitefly, Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae). B. bassiana isolates caused the highest mortality on thrips (some causing 88% mortality after 6 days); both fungal species caused similarly high mortality levels against whiteflies (75%) after 6 days. Large amounts of germplasm of entomopathogenic fungi, fundamentally B. bassiana and M. anisopliae, exist in the habitats sampled; pathogenicity varied among strains, and some strains possessed significant virulence. Soils in these habitats are reservoirs of diverse strains with potential for use in biocontrol. PMID:21521145

  19. Influences of extreme weather, climate and pesticide use on invertebrates in cereal fields over 42 years.

    PubMed

    Ewald, Julie A; Wheatley, Christopher J; Aebischer, Nicholas J; Moreby, Stephen J; Duffield, Simon J; Crick, Humphrey Q P; Morecroft, Michael B

    2015-11-01

    Cereal fields are central to balancing food production and environmental health in the face of climate change. Within them, invertebrates provide key ecosystem services. Using 42 years of monitoring data collected in southern England, we investigated the sensitivity and resilience of invertebrates in cereal fields to extreme weather events and examined the effect of long-term changes in temperature, rainfall and pesticide use on invertebrate abundance. Of the 26 invertebrate groups examined, eleven proved sensitive to extreme weather events. Average abundance increased in hot/dry years and decreased in cold/wet years for Araneae, Cicadellidae, adult Heteroptera, Thysanoptera, Braconidae, Enicmus and Lathridiidae. The average abundance of Delphacidae, Cryptophagidae and Mycetophilidae increased in both hot/dry and cold/wet years relative to other years. The abundance of all 10 groups usually returned to their long-term trend within a year after the extreme event. For five of them, sensitivity to cold/wet events was lowest (translating into higher abundances) at locations with a westerly aspect. Some long-term trends in invertebrate abundance correlated with temperature and rainfall, indicating that climate change may affect them. However, pesticide use was more important in explaining the trends, suggesting that reduced pesticide use would mitigate the effects of climate change. © 2015 John Wiley & Sons Ltd.

  20. Stable Reference Gene Selection for RT-qPCR Analysis in Nonviruliferous and Viruliferous Frankliniella occidentalis

    PubMed Central

    Pan, Huipeng; Ma, Yabin; Zhang, Deyong; Liu, Yong; Zhang, Zhanhong; Zheng, Changying; Chu, Dong

    2015-01-01

    Reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR) is a reliable technique for measuring and evaluating gene expression during variable biological processes. To facilitate gene expression studies, normalization of genes of interest relative to stable reference genes is crucial. The western flower thrips Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), the main vector of tomato spotted wilt virus (TSWV), is a destructive invasive species. In this study, the expression profiles of 11 candidate reference genes from nonviruliferous and viruliferous F. occidentalis were investigated. Five distinct algorithms, geNorm, NormFinder, BestKeeper, the ΔC t method, and RefFinder, were used to determine the performance of these genes. geNorm, NormFinder, BestKeeper, and RefFinder identified heat shock protein 70 (HSP70), heat shock protein 60 (HSP60), elongation factor 1 α, and ribosomal protein l32 (RPL32) as the most stable reference genes, and the ΔC t method identified HSP60, HSP70, RPL32, and heat shock protein 90 as the most stable reference genes. Additionally, two reference genes were sufficient for reliable normalization in nonviruliferous and viruliferous F. occidentalis. This work provides a foundation for investigating the molecular mechanisms of TSWV and F. occidentalis interactions. PMID:26244556

  1. Stable Reference Gene Selection for RT-qPCR Analysis in Nonviruliferous and Viruliferous Frankliniella occidentalis.

    PubMed

    Yang, Chunxiao; Li, Hui; Pan, Huipeng; Ma, Yabin; Zhang, Deyong; Liu, Yong; Zhang, Zhanhong; Zheng, Changying; Chu, Dong

    2015-01-01

    Reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR) is a reliable technique for measuring and evaluating gene expression during variable biological processes. To facilitate gene expression studies, normalization of genes of interest relative to stable reference genes is crucial. The western flower thrips Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), the main vector of tomato spotted wilt virus (TSWV), is a destructive invasive species. In this study, the expression profiles of 11 candidate reference genes from nonviruliferous and viruliferous F. occidentalis were investigated. Five distinct algorithms, geNorm, NormFinder, BestKeeper, the ΔCt method, and RefFinder, were used to determine the performance of these genes. geNorm, NormFinder, BestKeeper, and RefFinder identified heat shock protein 70 (HSP70), heat shock protein 60 (HSP60), elongation factor 1 α, and ribosomal protein l32 (RPL32) as the most stable reference genes, and the ΔCt method identified HSP60, HSP70, RPL32, and heat shock protein 90 as the most stable reference genes. Additionally, two reference genes were sufficient for reliable normalization in nonviruliferous and viruliferous F. occidentalis. This work provides a foundation for investigating the molecular mechanisms of TSWV and F. occidentalis interactions.

  2. Effect of new and old pesticides on Orius armatus (Gross) - an Australian predator of western flower thrips, Frankliniella occidentalis (Pergande).

    PubMed

    Broughton, Sonya; Harrison, Jessica; Rahman, Touhidur

    2014-03-01

    Orius armatus (Gross) is an important predator of western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) in Australian glasshouse grown sweet pepper. The failure of O. armatus to establish in some glasshouses has been attributed to the use of newer, more non-selective pesticides, some of which are regarded to be compatible with integrated pest management. The residual toxicity (via direct and indirect contact) of several older and newer chemistry pesticides were evaluated. In addition, the effect of several systemic insecticides through insecticide-treated food-chain uptake was tested. Older chemistry pesticides (methamidophos, dimethoate) were toxic to Orius armatus, except pirimicarb which was non-toxic. Newer chemistry pesticides differed in their suitability. Abamectin was toxic to adults and nymphs. Chlorantraniliprole, imidacloprid and spirotetramat were non-toxic. Spinosad and spinetoram were moderately toxic to O. armatus. Spinosad also reduced fecundity by 20% compared to the untreated control. Pymetrozine was non-toxic, but females exposed to treated beans produced 30% fewer eggs and 20% fewer nymphs hatched compared to the untreated control. The selective pesticides do not necessarily facilitate the conservation of beneficials, and further assessment of the various developmental stages and other sub-lethal effects of chlorantraniliprole, imidacloprid, pymetrozine, spinetoram, and spirotetramat is recommended. © 2013 Society of Chemical Industry.

  3. Habituation in Frankliniella occidentalis to deterrent plant compounds and their blends.

    PubMed

    Egger, Barbara; Spangl, Bernhard; Koschier, Elisabeth Helene

    2014-06-01

    Feeding and oviposition deterrence of three secondary plant compounds and their 1:1 blends to adult female Frankliniella occidentalis Pergande (Thysanoptera: Thripidae) and the potential for habituation of the thrips to the pure compounds and the 1:1 blends at various concentrations were investigated. In choice assays, we tested dose-dependent feeding and oviposition deterrence of the two fatty acid derivatives methyl jasmonate and cis -jasmone, the phenylpropanoid allylanisole, and their blends when directly applied to bean leaf discs. The concentration required to reduce the feeding damage by 50% relative to the control treatment (FDC 50 ) was lowest for cis -jasmone and highest for allylanisole. The feeding deterrent effect of both jasmonates was increased when blended with allylanisole. Feeding deterrence and oviposition deterrence were strongly correlated. In no-choice assays conducted over four consecutive days, we discovered that dilutions at low concentrations (FDC 15 ) applied to bean leaves resulted in habituation to the deterrents, whereas no habituation occurred at higher concentrations (FDC 50 ). We observed a tendency that the 1:1 blends reduce the probability that thrips habituate to the deterrent compounds. Our results may be useful in the development of integrated crop protection strategies with the implementation of allelochemicals as pest behaviour-modifying agents.

  4. Market-based Instruments for optimal control of Invasive Insect Species: B. tabaci in Arizona.

    USDA-ARS?s Scientific Manuscript database

    Invasive insect species represent a significant economic risk to both the financial viability of agricultural producers and to the sustainability of U.S. agriculture more generally. With the rapid growth of international trade in agricultural commodities of all types, agricultural systems in the U.S...

  5. Temperature stress, anti-oxidative enzyme activity and virus acquisition in Bemisia tabaci (Hemiptera: Aleyrodidae)

    USDA-ARS?s Scientific Manuscript database

    In most eukaryotic systems, antioxidants provide protection when cells are exposed to stressful environmental conditions. Antioxidants, such as superoxide dismutase (SOD), glutathione peroxidase (GPX) and catalase, function in a stepwise series with SOD initially preventing oxidative damage by conve...

  6. Cytoplastic Glyceraldehyde-3-Phosphate Dehydrogenases Interact with ATG3 to Negatively Regulate Autophagy and Immunity in Nicotiana benthamiana

    PubMed Central

    Han, Shaojie; Wang, Yan; Zheng, Xiyin; Jia, Qi; Zhao, Jinping; Bai, Fan; Hong, Yiguo; Liu, Yule

    2015-01-01

    Autophagy as a conserved catabolic pathway can respond to reactive oxygen species (ROS) and plays an important role in degrading oxidized proteins in plants under various stress conditions. However, how ROS regulates autophagy in response to oxidative stresses is largely unknown. Here, we show that autophagy-related protein 3 (ATG3) interacts with the cytosolic glyceraldehyde-3-phosphate dehydrogenases (GAPCs) to regulate autophagy in Nicotiana benthamiana plants. We found that oxidative stress inhibits the interaction of ATG3 with GAPCs. Silencing of GAPCs significantly activates ATG3-dependent autophagy, while overexpression of GAPCs suppresses autophagy in N. benthamiana plants. Moreover, silencing of GAPCs enhances N gene-mediated cell death and plant resistance against both incompatible pathogens Tobacco mosaic virus and Pseudomonas syringae pv tomato DC3000, as well as compatible pathogen P. syringae pv tabaci. These results indicate that GAPCs have multiple functions in the regulation of autophagy, hypersensitive response, and plant innate immunity. PMID:25829441

  7. Feeding by whiteflies suppresses downstream jasmonic acid signaling by eliciting salicylic acid signaling.

    PubMed

    Zhang, Peng-Jun; Li, Wei-Di; Huang, Fang; Zhang, Jin-Ming; Xu, Fang-Cheng; Lu, Yao-Bin

    2013-05-01

    Phloem-feeding whiteflies in the species complex Bemisia tabaci cause extensive crop damage worldwide. One of the reasons for their "success" is their ability to suppress the effectual jasmonic acid (JA) defenses of the host plant. However, little is understood about the mechanisms underlying whitefly suppression of JA-regulated defenses. Here, we showed that the expression of salicylic acid (SA)-responsive genes (EDS1 and PR1) in Arabidopsis thaliana was significantly enhanced during feeding by whitefly nymphs. Whereas upstream JA-responsive genes (LOX2 and OPR3) also were induced, the downstream JA-responsive gene (VSP1) was repressed, i.e., whiteflies only suppressed downstream JA signaling. Gene-expression analyses with various Arabidopsis mutants, including NahG, npr-1, ein2-1, and dde2-2, revealed that SA signaling plays a key role in the suppression of downstream JA defenses by whitefly feeding. Assays confirmed that SA activation enhanced whitefly performance by suppressing downstream JA defenses.

  8. A multiplex PCR method discriminating between the TYLCV and TYLCV-Mld clades of tomato yellow leaf curl virus.

    PubMed

    Lefeuvre, P; Hoareau, M; Delatte, H; Reynaud, B; Lett, J-M

    2007-09-01

    Tomato yellow leaf curl virus (TYLCV) is one of the causal agents of tomato yellow leaf curl disease (TYLCD) and can cause up to 100% yield losses in tomato fields. As TYLCV continues to spread, many isolates have been described in different parts of the world. Recently two closely related but distinct TYLCV clades, called TYLCV and TYLCV-Mld, have been identified. Isolates from those two clades differ mainly in the nucleotide sequences of their replication associated protein genes but do not display significantly different symptomatology. In order to improve monitoring of the rapidly expanding worldwide TYLCD epidemic, a multiplex polymerase chain reaction assay (mPCR) was developed. A set of three primers were designed to detect and characterize the TYLCV and TYLCV-Mld clade isolates. The specificity and sensitivity of the mPCR were validated on TYLCV infected tomato plants and Bemisia tabaci whiteflies. Being cheap, fast and highly sensitive this new diagnostic tool should greatly simplify efforts to trace the global spread of TYLCV.

  9. Evaluation of insecticides for curative, preventative and rotational use on Scirtothrips dorsalis South Asia 1 (Thysanoptera: Thripidae)

    USDA-ARS?s Scientific Manuscript database

    The chilli thrips, Scirtothrips dorsalis Hood is a cryptic species complex of at least nine different species, two (South Asia 1 and East Asia 1) of which exists in the United States. In order to integrate chemical and biological insecticides in the preventive and therapeutic tactics used for Scirto...

  10. Imidacloprid effects on probing and settling behavior of Frankliniella fusca and Frankliniella occidentalis (Thysanoptera: Thripidae) in tomato.

    PubMed

    Joost, P Houston; Riley, David G

    2005-10-01

    The effects of tomato, Lycopersicum spp., leaves treated with imidacloprid on probing and settling behavior of Frankliniella fusca (Hinds) and Frankliniella occidentalis (Pergrande) were examined using an electrical penetration graph technique and an intact leaf bioassay. For each experiment, thrips were subjected to nontreated plants and plants treated with either of two rates of imidacloprid: 7.81 and 41.55 microg [(AI)] per plant. F. fusca probed less frequently on plants treated with the high rate of imidacloprid compared with the nontreated plants. The duration of F. fusca noningestion probing waveforms and ingestion was shorter on plants treated with the high rate of imidacloprid compared with that on nontreated plants. In contrast, F. occidentalis probed longer and more frequently on plants treated with either the low or high imidacloprid rates compared with nontreated plants. They also ingested more frequently and for longer durations on plants treated with the high rate compared with nontreated plants. The duration and frequency of noningesting probing waveforms were greater on the imidacloprid-treated plants compared with the nontreated plants. F. occidentalis probed and ingested more frequently and for a longer duration than F. fusca on plants treated with the high rate of imidacloprid. F. fusca ingested more frequently and the duration of ingestion was longer than F. occidentalis in untreated plants. F. fusca and F. occidentalis settling behavior differed within the first 30 min in a choice bioassay. F. fusca preferred settling on leaves of nontreated plants, whereas F. occidentalis showed no preference in an intact leaf choice bioassay.

  11. Ultralow oxygen treatment for control of western flower thrips, frankliniella occidentalis (thysanoptera: thripidae), on harvested table grapes

    USDA-ARS?s Scientific Manuscript database

    Western flower thrips, Frankliniella occidentalis (Pergande), is a common pest on grapes and other fresh commodities in the United States, but a quarantined pest in Taiwan. Methyl bromide fumigation has been used to control the thrips on U.S. exported fresh commodities, including organic table grap...

  12. Host plant, temperature, and photoperiod effects on ovipositional preference of Frankliniella occidentalis and Frankliniella fusca (Thysanoptera: Thripidae).

    PubMed

    Chaisuekul, C; Riley, D G

    2005-12-01

    Host plant effects of tomato, Lycopersicon esculentum Mill., and chickweed, Stellaria media (L.) Vill., foliage infected and uninfected with Tomato spotted wilt virus (family Bunyaviridae, genus Tospovirus, TSWV) on the ovipositional preferences of western flower thrips, Frankliniella occidentalis (Pergande), and tobacco thrips, Frankliniella fusca (Hinds), were investigated for whole plants in the greenhouse. In addition, the preference for leaf disks from the same host plants was investigated under a range of temperatures, 15-30 degrees C at a photoperiod of 12:12 (L:D) h, and at three photoperiods, 6:18, 12:12, and 18:6, at 20 degrees C in no-choice and choice studies conducted in growth chambers. In a choice test, F. fusca oviposited significantly more eggs per whole plant foliage over a 7-d period than F. occidentalis by an average ratio of 3:1 over both tomato and chickweed. The optimum temperature for oviposition of F. occidentalis and F. fusca was 24.5 and 24.9 degrees C, respectively. Both species laid significantly more eggs under the longest daylight hours tested, 18:6, in the choice study. Temperature and photoperiod did not significantly interact in terms of thrips ovipositional preference. Ovipositional preference for chickweed or tomato foliage was different for each thrips species in the choice and no-choice tests. However, both thrips species laid significantly more eggs per square centimeter of leaf area in chickweed than in tomato in the whole plant choice test.

  13. Evaluation of Dicyphus hersperus (Heteroptera: Miridae) for biological control of Frankliniella occidentalis (Thysanoptera: Thripidae) on greenhouse tomato.

    PubMed

    Shipp, J L; Wang, K

    2006-04-01

    The effectiveness of inoculative releases of the mirid predator Dicyphus hesperus Knight for control of Frankliniella occidentalis (Pergande) on greenhouse tomatoes was evaluated in terms of suppression of the population densities of F. occidentalis and associated fruit damage in the presence of the predator over two seasonal trials. An inoculative release of one D. hesperus per plant (approximately 0.1:10 predator:prey ratio) at a high F. occidentalis population density (140 thrips per plant) suppressed the thrips population density to a significantly lower level, compared with the nonrelease greenhouse, but not below a thrips level that caused economic fruit damage. As the predator:prey ratio increased to approximately 0.5:10 D. hesperus:F. occidentalis, the mean percentage of the thrips-damaged fruit in the D. hesperus release greenhouse decreased to 1.6%. However, the amount of fruit feeding by D. hesperus was highly correlated to the availability of prey (or predator:prey ratio) under greenhouse conditions. D. hesperus-induced fruit damage occurred when the predator:prey ratio was >1:10 D. hesperus:F. occidentalis. Considering the potential risk of fruit damage by D. hesperus and the need for effective control of F. occidentalis, a 0.5-1:10 D. hesperus:F. occidentalis ratio is recommended when the thrips population density is in the range of 60-150 thrips per plant.

  14. Species of the Poaceae-associated genus Bamboosiella (Thysanoptera, Phlaeothripidae) from China, with three new species.

    PubMed

    Dang, Li-Hong; Qiao, Ge-Xia

    2016-11-07

    In the Poaceae-associated genus Bamboosiella Ananthakrishnan, eleven species are here recognized from China, including antennatus sp.n. and longisetis sp.n. from Yunnan, and magnus sp.n. from Hainan. Four species are newly recorded from China, bicoloripes Ananthakrishnan, fasciata Okajima, flavescens Okajima and semiflava Okajima. One species from Zhejiang, Bamboosiella brevibristla Sha, Guo, Feng & Duan is placed as a new synonym of B. exastis (Ananthakrishnan & Kudo). An illustrated identification key is provided to the eleven Bamboosiella species now recognised from China.

  15. The invasive MED/Q Bemisia tabaci genome: a tale of gene loss and gene gain

    USDA-ARS?s Scientific Manuscript database

    Whiteflies are a group of invasive crop pests that impact global agriculture. An analysis was conducted to compare draft genomes of two whitefly strains, which demonstrated the relative conserved gene order, but a number of genes were either novel (added) or omitted (deleted) between genomes. This...

  16. Effect of foliar application of pyrifluquinazon on Bemisia tabaci (MED whitefly) and Amblyseius swirskii, 2016

    USDA-ARS?s Scientific Manuscript database

    With the overall goal to integrate the predatory mite Amblyseius swirskii in the management program of MED whitefly, the specific objective of this study was to evaluate pyrifluquinazon, a pyridine insecticide for whitefly control, and assess its compatibility with swirskii mite, and assess its comp...

  17. Evolution and homoplasy at the bem6 microsatellite locus in three Bemisia tabaci cryptic species

    USDA-ARS?s Scientific Manuscript database

    The evolution of individual microsatellite loci is often complex and homoplasy is common but often goes undetected. Sequencing alleles at a microsatellite locus can provide a more complete picture of the common evolutionary mechanisms occurring at that locus and can reveal cases of homoplasy. Within...

  18. Evaluation of potential new sources of melon host plant resistance to the whitefly, Bemisia tabaci

    USDA-ARS?s Scientific Manuscript database

    Melon (Cucumis melo L.) genotypes that support fewer numbers of whitefly could reduce the frequency or the amount of insecticide applications required to keep the insects in check, as was the case with cotton where measurable resistance to whitefly in some genotypes reduced the number of sprays, thu...

  19. Active aggregation among sexes in bean flower thrips (Megalurothrips sjostedti) on cowpea (Vigna unguiculata)

    PubMed Central

    Niassy, Saliou; Ekesi, Sunday; Maniania, Nguya K; Orindi, Benedict; Moritz, Gerald B; de Kogel, Willem J; Subramanian, Sevgan

    2016-01-01

    Male sexual aggregations are a common territorial, mating-related or resource-based, behaviour observed in diverse organisms, including insects such as thrips. The influence of factors such as plant substrate, time of day, and geographic location on aggregation of thrips is uncertain, therefore we monitored the dispersion of male and female bean flower thrips (BFT), Megalurothrips sjostedti (Trybom) (Thysanoptera: Thripidae), on cowpea, Vigna unguiculata (L.) Walp. (Fabaceae), over three cowpea growth stages and across three cowpea-growing areas of Kenya. Our results indicated that for all the crop growth stages, the density of BFTs varied over the time of day, with higher densities at 10:00, 13:00, and 16:00 hours than at 07:00 hours. Thrips densities did not differ among blocks at the budding stage, but they did at peak flowering and podding stages. Dispersion indices suggested that both male and female BFTs were aggregated. Active male aggregation occurred only on green plant parts and it varied across blocks, crop stages, and locations. Similarly, active female aggregation was observed in peak flowering and podding stages. Such active aggregation indicates a semiochemical or behaviour-mediated aggregation. Identification of such a semiochemical may offer new opportunities for refining monitoring and management strategies for BFT on cowpea, the most important grain legume in sub-Saharan Africa. PMID:26726262

  20. Colored Sticky Traps to Selectively Survey Thrips in Cowpea Ecosystem.

    PubMed

    Tang, L D; Zhao, H Y; Fu, B L; Han, Y; Liu, K; Wu, J H

    2016-02-01

    The bean flower thrips, Megalurothrips usitatus (Bagrall) (Thysanoptera: Thripidae), is an important pest of legume crops in South China. Yellow, blue, or white sticky traps are currently recommended for monitoring and controlling thrips, but it is not known whether one is more efficient than the other or if selectivity could be optimized by trap color. We investigated the response of thrips and beneficial insects to different-colored sticky traps on cowpea, Vigna unguiculata. More thrips were caught on blue, light blue, white, and purple traps than on yellow, green, pink, gray, red, or black traps. There was a weak correlation on the number of thrips caught on yellow traps and survey from flowers (r = 0.139), whereas a strong correlation was found for blue traps and thrips' survey on flowers (r = 0.929). On commercially available sticky traps (Jiaduo®), two and five times more thrips were caught on blue traps than on white and yellow traps, respectively. Otherwise, capture of beneficial insects was 1.7 times higher on yellow than on blue traps. The major natural enemies were the predatory ladybird beetles (63%) and pirate bugs Orius spp. (29%), followed by a number of less representative predators and parasitoids (8%). We conclude the blue sticky trap was the best to monitor thrips on cowpea in South China.

  1. Active aggregation among sexes in bean flower thrips (Megalurothrips sjostedti) on cowpea (Vigna unguiculata).

    PubMed

    Niassy, Saliou; Ekesi, Sunday; Maniania, Nguya K; Orindi, Benedict; Moritz, Gerald B; de Kogel, Willem J; Subramanian, Sevgan

    2016-01-01

    Male sexual aggregations are a common territorial, mating-related or resource-based, behaviour observed in diverse organisms, including insects such as thrips. The influence of factors such as plant substrate, time of day, and geographic location on aggregation of thrips is uncertain, therefore we monitored the dispersion of male and female bean flower thrips (BFT), Megalurothrips sjostedti (Trybom) (Thysanoptera: Thripidae), on cowpea, Vigna unguiculata (L.) Walp. (Fabaceae), over three cowpea growth stages and across three cowpea-growing areas of Kenya. Our results indicated that for all the crop growth stages, the density of BFTs varied over the time of day, with higher densities at 10:00, 13:00, and 16:00 hours than at 07:00 hours. Thrips densities did not differ among blocks at the budding stage, but they did at peak flowering and podding stages. Dispersion indices suggested that both male and female BFTs were aggregated. Active male aggregation occurred only on green plant parts and it varied across blocks, crop stages, and locations. Similarly, active female aggregation was observed in peak flowering and podding stages. Such active aggregation indicates a semiochemical or behaviour-mediated aggregation. Identification of such a semiochemical may offer new opportunities for refining monitoring and management strategies for BFT on cowpea, the most important grain legume in sub-Saharan Africa.

  2. The effect of latitudinal gradient on the species diversity of Chinese litter-dwelling thrips

    PubMed Central

    Wang, Jun; Tong, Xiaoli; Wu, Donghui

    2014-01-01

    Abstract To understand the global distribution patterns of litter-dwelling thrips, a total 150 leaf litter samples were collected from 6 natural reserves located in three climatic regions, temperate, subtropical and tropical. The results showed the relative abundance of Thysanoptera was over 3.0% in 4 natural reserves from subtropical and tropical zone, and reached 5.9% in one tropical reserve, only less than Acarina and Collembola. In contrast it was only 0.3% in the warm temperate natural reserves, and no thrips were collected in a mid temperate reserve. The order on the average species numbers per plot of litter thrips was tropic > subtropics > temperate (n=25, p<0.05). Mean density of litter thrips per plots in the tropics and subtropics was significantly higher than that in the temperate region (n=25, p<0.05), but the average density was not significantly different between tropical and subtropical zones (n=25, p>0.05). The diversity of litter thrips in the tropics and subtropics was much higher than that in the temperate area based on comparsions of Shannon-Wiener diversity index (H’), Pielou eveness index (J), and Simpson dominance index (D). All of these results indicated that litter-dwelling thrips lived mainly in tropical and subtropical regions; meanwhile, species number and relative abundance increased with decreasing latitude. PMID:25061351

  3. Development and Characterization of 18 Novel EST-SSRs from the Western Flower Thrips, Frankliniella occidentalis (Pergande)

    PubMed Central

    Yang, Xian-Ming; Sun, Jing-Tao; Xue, Xiao-Feng; Zhu, Wen-Chao; Hong, Xiao-Yue

    2012-01-01

    The western flower thrips, Frankliniella occidentalis (Pergande), is an invasive species and the most economically important pest within the insect order Thysanoptera. For a better understanding of the genetic makeup and migration patterns of F. occidentalis throughout the world, we characterized 18 novel polymorphic EST-derived microsatellites. The mutational mechanism of these EST-SSRs was also investigated to facilitate the selection of appropriate combinations of markers for population genetic studies. Genetic diversity of these novel markers was assessed in 96 individuals from three populations in China (Harbin, Dali, and Guiyang). The results showed that all these 18 loci were highly polymorphic; the number of alleles ranged from 2 to 15, with an average of 5.50 alleles per locus. The observed (HO) and expected (HE) heterozygosities ranged from 0.072 to 0.707 and 0.089 to 0.851, respectively. Furthermore, only two locus/population combinations (WFT144 in Dali and WFT50 in Guiyang) significantly deviated from Hardy–Weinberg equilibrium (HWE). Pairwise FST analysis showed a low but significant differentiation (0.026 < FST < 0.032) among all three pairwise population comparisons. Sequence analysis of alleles per locus revealed a complex mutational pattern of these EST-SSRs. Thus, these EST-SSRs are useful markers but greater attention should be paid to the mutational characteristics of these microsatellites when they are used in population genetic studies. PMID:22489130

  4. Continuous exposure to the deterrents cis-jasmone and methyl jasmonate does not alter the behavioural responses of Frankliniella occidentalis.

    PubMed

    Egger, Barbara; Spangl, Bernhard; Koschier, Elisabeth Helene

    2016-01-01

    Behavioural responses of Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), a generalist, cell sap-feeding insect species with piercing-sucking mouthparts, after continuous exposure to two deterrent secondary plant compounds are investigated. We compared in choice assays on bean leaf discs, the settling, feeding, and oviposition preferences of F. occidentalis females that had no experience with the two fatty acid derivatives methyl jasmonate and cis -jasmone before testing (naïve thrips) vs. females that had been exposed to the deterrent compounds before testing (experienced thrips). The thrips were exposed to the deterrents at low or high concentrations for varied time periods and subsequently tested on bean leaf discs treated with the respective deterrent at either a low or a high concentration. Frankliniella occidentalis females avoided settling on the deterrent-treated bean leaf discs for an observation period of 6 h, independent of their previous experience. Our results demonstrate that feeding and oviposition deterrence of the jasmonates to the thrips were not altered by continuous exposure of the thrips to the jasmonates. Habituation was not induced, neither by exposure to the low concentration of the deterrents nor by exposure to the high concentration. These results indicate that the risk of habituation to two volatile deterrent compounds after repeated exposure is not evident in F. occidentalis . This makes the two compounds potential candidates to be integrated in pest management strategies.

  5. Development and characterization of 18 novel EST-SSRs from the western flower Thrips, Frankliniella occidentalis (Pergande).

    PubMed

    Yang, Xian-Ming; Sun, Jing-Tao; Xue, Xiao-Feng; Zhu, Wen-Chao; Hong, Xiao-Yue

    2012-01-01

    The western flower thrips, Frankliniella occidentalis (Pergande), is an invasive species and the most economically important pest within the insect order Thysanoptera. For a better understanding of the genetic makeup and migration patterns of F. occidentalis throughout the world, we characterized 18 novel polymorphic EST-derived microsatellites. The mutational mechanism of these EST-SSRs was also investigated to facilitate the selection of appropriate combinations of markers for population genetic studies. Genetic diversity of these novel markers was assessed in 96 individuals from three populations in China (Harbin, Dali, and Guiyang). The results showed that all these 18 loci were highly polymorphic; the number of alleles ranged from 2 to 15, with an average of 5.50 alleles per locus. The observed (H(O)) and expected (H(E)) heterozygosities ranged from 0.072 to 0.707 and 0.089 to 0.851, respectively. Furthermore, only two locus/population combinations (WFT144 in Dali and WFT50 in Guiyang) significantly deviated from Hardy-Weinberg equilibrium (HWE). Pairwise F(ST) analysis showed a low but significant differentiation (0.026 < F(ST) < 0.032) among all three pairwise population comparisons. Sequence analysis of alleles per locus revealed a complex mutational pattern of these EST-SSRs. Thus, these EST-SSRs are useful markers but greater attention should be paid to the mutational characteristics of these microsatellites when they are used in population genetic studies.

  6. Perception of solar UVB radiation by phytophagous insects: Behavioral responses and ecosystem implications

    PubMed Central

    Mazza, Carlos A.; Zavala, Jorge; Scopel, Ana L.; Ballaré, Carlos L.

    1999-01-01

    Most of our present knowledge about the impacts of solar UVB radiation on terrestrial ecosystems comes from studies with plants. Recently, the effects of UVB on the growth and survival of consumer species have begun to receive attention, but very little is known about UVB impacts on animal behavior. Here we report that manipulations of the flux of solar UVB received by field-grown soybean crops had large and consistent effects on the density of the thrips (Caliothrips phaseoli, Thysanoptera: Thripidae) populations that invaded the canopies, as well as on the amount of leaf damage caused by the insects. Solar UVB strongly reduced thrips herbivory. Thrips not only preferred leaves from plants that were not exposed to solar UVB over leaves from UVB-exposed plants in laboratory and field choice experiments, but they also appeared to directly sense and avoid exposure to solar UVB. Additional choice experiments showed that soybean leaf consumption by the late-season soybean worm Anticarsia gemmatalis (Lepidoptera: Noctuidae) was much less intense in leaves with even slight symptoms of an early thrips attack than in undamaged leaves. These experiments suggest that phytophagous insects can present direct and indirect behavioral responses to solar UVB. The indirect responses are mediated by changes in the plant host that are induced by UVB and, possibly, by other insects whose behavior is affected by UVB. PMID:9927679

  7. New tropical fruit hosts of Scirtothrips dorsalis (Thysanoptera: Thripidae) and its relative abundance on them in South Florida

    USDA-ARS?s Scientific Manuscript database

    Chilli thrips, Scritothrips dorsalis Hood, recently established in the southeast region of the United States, poses an economic threat to a wide-range of ornamental and vegetable plants. During scouting and sampling various hosts at different commercial nursery locations in Florida (Miami-Dade Count...

  8. Field-evolved resistance to insecticides in the invasive western flower thrips Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) in China.

    PubMed

    Wang, Ze-Hua; Gong, Ya-Jun; Jin, Gui-Hua; Li, Bing-Yan; Chen, Jin-Cui; Kang, Zong-Jiang; Zhu, Liang; Gao, Yu-Lin; Reitz, Stuart; Wei, Shu-Jun

    2016-07-01

    To understand the current status of insecticide resistance of the invasive western flower thrips, Frankliniella occidentalis, in China, the responses of six field populations to six commonly used insecticides, i.e. spinosad, spinetoram, cyantraniliprole, imidacloprid, acetamiprid and pyriproxyfen, were evaluated in comparison with a susceptible laboratory strain. Field populations tended to be less susceptible than the laboratory strain. The population from Shouguang, Shandong Province, showed the lowest levels of susceptibility. A 15.64-fold and 17.29-fold resistance to spinosad and spinetoram was detected in the Shouguang population. A 11.74-fold and 13.64-fold resistance to cyantraniliprole was detected in populations from Daxing in the Beijing area and Shouguang. All populations showed a low level of resistance to imidacloprid, acetamiprid and pyriproxyfen, except for the Shouguang population, which was 127.58-fold more resistant to pyriproxyfen. Variations in resistance to the tested insecticides were observed among the sampled population. Spinosad and spinetoram were the most efficient insecticides and are recommended for use in an integrated management programme. Resistance management strategies should be implemented to reduce the potential for resistance evolving. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  9. Molecular cloning and characterization of an Hsp90/70 organizing protein gene from Frankliniella occidentalis (Insecta: Thysanoptera, Thripidae).

    PubMed

    Li, Hong-Bo; Du, Yu-Zhou

    2013-05-15

    The heat shock 90/70 organizing protein (Hop), also known as Sti-1 (stress-induced protein-1), is a co-chaperone that usually mediates the interaction of Hsp90 and Hsp70 and has been extensively characterized in mammals and plants. However, its role in insects remains unknown. In the present study, we isolated and characterized a Hop homologue gene from Frankliniella occidentalis (Fohop). The Fohop contains a 1659bp ORF encoding a protein of 552 amino acids with a caculated molecular mass of approximately 62.25kDa, which displays a reasonable degree of identity with the known Hops and shares several canonical motifs, including three tetratricopeptide repeated motif domains (TPR1, TPR2A and TPR2B) and two aspartic acid-proline (DP) repeat motifs (DP1 and DP2). As in other hops, Fohop contains introns, but the number and the position are quite variable. The mRNA expression patterns indicated that Fohop was constitutively expressed throughout the developmental stages, but was obviously upregulated by heat stress both in larvae and adults. Our studies imply that Hop, as in other Hsps, may play an important role in heat shock response of F. occidentalis. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. Complete nucleotide sequences of a new bipartite begomovirus from Malvastrum sp. plants with bright yellow mosaic symptoms in South Texas.

    PubMed

    Alabi, Olufemi J; Villegas, Cecilia; Gregg, Lori; Murray, K Daniel

    2016-06-01

    Two isolates of a novel bipartite begomovirus, tentatively named malvastrum bright yellow mosaic virus (MaBYMV), were molecularly characterized from naturally infected plants of the genus Malvastrum showing bright yellow mosaic disease symptoms in South Texas. Six complete DNA-A and five DNA-B genome sequences of MaBYMV obtained from the isolates ranged in length from 2,608 to 2,609 nucleotides (nt) and 2,578 to 2,605 nt, respectively. Both genome segments shared a 178- to 180-nt common region. In pairwise comparisons, the complete DNA-A and DNA-B sequences of MaBYMV were most similar (87-88 % and 79-81 % identity, respectively) and phylogenetically related to the corresponding sequences of sida mosaic Sinaloa virus-[MX-Gua-06]. Further analysis revealed that MaBYMV is a putative recombinant virus, thus supporting the notion that malvaceous hosts may be influencing the evolution of several begomoviruses. The design of new diagnostic primers enabled the detection of MaBYMV in cohorts of Bemisia tabaci collected from symptomatic Malvastrum sp. plants, thus implicating whiteflies as potential vectors of the virus.

  11. A molecular insight into papaya leaf curl-a severe viral disease.

    PubMed

    Varun, Priyanka; Ranade, S A; Saxena, Sangeeta

    2017-11-01

    Papaya leaf curl disease (PaLCuD) caused by papaya leaf curl virus (PaLCuV) not only affects yield but also plant growth and fruit size and quality of papaya and is one of the most damaging and economically important disease. Management of PaLCuV is a challenging task due to diversity of viral strains, the alternate hosts, and the genomic complexities of the viruses. Several management strategies currently used by plant virologists to broadly control or eliminate the viruses have been discussed. In the absence of such strategies in the case of PaLCuV at present, the few available options to control the disease include methods like removal of affected plants from the field, insecticide treatments against the insect vector (Bemisia tabaci), and gene-specific control through transgenic constructs. This review presents the current understanding of papaya leaf curl disease, genomic components including satellite DNA associated with the virus, wide host and vector range, and management of the disease and suggests possible generic resistance strategies.

  12. A transgenic approach to control hemipteran insects by expressing insecticidal genes under phloem-specific promoters.

    PubMed

    Javaid, Shaista; Amin, Imran; Jander, Georg; Mukhtar, Zahid; Saeed, Nasir A; Mansoor, Shahid

    2016-10-06

    The first generation transgenic crops used strong constitutive promoters for transgene expression. However, tissue-specific expression is desirable for more precise targeting of transgenes. Moreover, piercing/sucking insects, which are generally resistant to insecticidal Bacillus thuringiensis (Bt) proteins, have emerged as a major pests since the introduction of transgenic crops expressing these toxins. Phloem-specific promoters isolated from Banana bunchy top virus (BBTV) were used for the expression of two insecticidal proteins, Hadronyche versuta (Blue Mountains funnel-web spider) neurotoxin (Hvt) and onion leaf lectin, in tobacco (Nicotiana tabacum). Here we demonstrate that transgenic plants expressing Hvt alone or in combination with onion leaf lectin are resistant to Phenacoccus solenopsis (cotton mealybug), Myzus persicae (green peach aphids) and Bemisia tabaci (silver leaf whitefly). The expression of both proteins under different phloem-specific promoters resulted in close to 100% mortality and provided more rapid protection than Hvt alone. Our results suggest the employment of the Hvt and onion leaf lectin transgenic constructs at the commercial level will reduce the use of chemical pesticides for control of hemipteran insect pests.

  13. New developments in insecticide resistance in the glasshouse whitefly (Trialeurodes vaporariorum) and the two-spotted spider mite (Tetranychus urticae) in the UK.

    PubMed

    Gorman, Kevin; Hewitt, Fiona; Denholm, Ian; Devine, Gregor J

    2002-02-01

    A recent survey of insecticide resistance in two of the most problematic pests in UK glasshouses revealed some new developments. At least some individuals in all UK samples of Trialeurodes vaporariorum that were tested resisted the insect growth regulator (IGR) buprofezin. The most strongly resistant strains were unaffected by the field application rate of this compound, and even samples from populations that had never been exposed to buprofezin contained individuals that survived the highest concentration applied (10,000 mg litre-1). The field rate of buprofezin was shown to select for resistance through vapour action alone. The benzophenylurea teflubenzuron, an unrelated IGR, was cross-resisted by buprofezin-resistant individuals. There was no evidence of resistance to imidacloprid, but all T vaporariorum strains tested, regardless of origin, exhibited a high innate tolerance to nicotine, when compared with another whitefly species, Bemisia tabaci. Marked resistance to fenbutatin oxide and tebufenpyrad was found in single glasshouse populations of Tetranychus urticae, but these compounds and abamectin appeared to remain highly effective against all other strains collected.

  14. A Tomato necrotic dwarf virus isolate from Datura with poor transmissibility by the whitefly, Bemisia tabaci

    USDA-ARS?s Scientific Manuscript database

    Tomato necrotic dwarf virus (ToNDV); genus Torradovirus, is a whitefly-transmitted virus that caused significant losses for tomato production in the Imperial Valley of California during the 1980s. The virus causes severe stunting, dwarfing of leaves, foliar and fruit necrosis, and greatly reduced f...

  15. Comparing an ecosystem approach to single-species stock assessment: The case of Gazi Bay, Kenya

    NASA Astrophysics Data System (ADS)

    Tuda, Paul M.; Wolff, Matthias

    2018-08-01

    Gazi Bay located on the Kenyan South Coast is a semi-enclosed shallow tropical coastal ecosystem supporting an economically important multi-species and multi-gear artisanal fishery. In this study, we integrated the available scientific information of the system to develop a preliminary trophic mass-balance model to characterize the ecosystem structure and functioning, evaluate the ecological impacts of fishing on the ecosystem, and compare the results of the ecosystem assessment to those of previous single-species stock assessments. The model includes 23 functional groups aggregated into linear food chains, which resulted in nine discrete trophic levels sensu Lindeman (1942). Results from the mixed trophic impacts showed a bottom-up control in the system where herbivory dominated the energy flow to higher trophic levels but with a significant export of detritus out of the system. With a mean transfer efficiency of 12.6%, Finn cycling index 7.3%, path length 2.7, system omnivory index 0.19, and system ascendency and overhead 27 and 73%, respectively, it would appear that Gazi Bay is immature and perturbed likely due to fishery-induced exploitation. Overall, the fishery is operating at a level of primary consumers with a mean trophic level of the catch of 2.38. Fishing mortality is by far the leading cause of total mortality with the computed exploitation rates suggesting heavy exploitation of the key commercial species (F/Z > 0.5). A comparison of the results of the percentage of primary production required to sustain fisheries and the average trophic level of catch (%PPR-TLc) with those from similar tropical coastal systems shows that Gazi Bay is comparable to some of the most intensively exploited coastal ecosystems. This implies the impacts of the fishery are evident both at the species and ecosystem level, and there may be a need for precautionary measures for fisheries management.

  16. Reptilia: Testudines: Emydidae Graptemys gibbonsi - Pascagoula Map Turtle

    USGS Publications Warehouse

    Lovich, Jeffrey E.; Ennen, Joshua R.

    2014-01-01

    The Pascagoula Map Turtle, Graptemys gibbonsi, is a large riverine species that exhibits pronounced sexual dimorphism, where females attain a maximum carapace length (CL) of 295 mm and males a maximum of 141 mm (Lovich et al. 2009). Mean adult female CL (248 mm) can be well over twice the mean CL of adult males (104 mm; Gibbons and Lovich 1990, Lovich et al. 2009). In addition, females have conspicuously enlarged heads (37.9 mm, SD = 14.0 mm) with broad alveolar surfaces (12.1 mm, SD = 4.9) compared to males (head width – 16.4 mm, SD = 1.1 mm; alveolar width – 4.3 mm, SD = 0.40 mm; Lindeman, unpublished data). Males have longer tails with the vent posterior to the edge of the carapace. Both sexes have relatively flat plastrons. Similar to other species within the pulchra clade, Graptemys gibbonsi possess a high-domed shell with a median keel. The median carapace keel is composed of prominent spines on the posterior portions of the second and third vertebrals. A broken black stripe, most pronounced anteriorly, marks the median keel of the vertebrals, and pleural scutes 1– 3 have a network of intersecting yellow lines or circular yellow markings on the distal parts. The plastron is pale yellow with dark pigment on some seams. Ground color of the head and limbs is brown to olive with light yellow or yellowish-green stripes and blotches. The yellow pigment on the upper marginal scutes is wide in comparison to other members of the pulchra clade.Hatchling pigmentation patterns resemble those of adults, but with more conspicuous patterns on the pleural scutes. Similarly, the plastron of hatchlings commonly has more dark pigmentation along the seams than adults. The shell is highly serrated along the edge of the carapace and the vertebral keel is more pronounced than in adults.

  17. A hybrid constructed wetland for organic-material and nutrient removal from sewage: Process performance and multi-kinetic models.

    PubMed

    Nguyen, X Cuong; Chang, S Woong; Nguyen, Thi Loan; Ngo, H Hao; Kumar, Gopalakrishnan; Banu, J Rajesh; Vu, M Cuong; Le, H Sinh; Nguyen, D Duc

    2018-09-15

    A pilot-scale hybrid constructed wetland with vertical flow and horizontal flow in series was constructed and used to investigate organic material and nutrient removal rate constants for wastewater treatment and establish a practical predictive model for use. For this purpose, the performance of multiple parameters was statistically evaluated during the process and predictive models were suggested. The measurement of the kinetic rate constant was based on the use of the first-order derivation and Monod kinetic derivation (Monod) paired with a plug flow reactor (PFR) and a continuously stirred tank reactor (CSTR). Both the Lindeman, Merenda, and Gold (LMG) analysis and Bayesian model averaging (BMA) method were employed for identifying the relative importance of variables and their optimal multiple regression (MR). The results showed that the first-order-PFR (M 2 ) model did not fit the data (P > 0.05, and R 2  < 0.5), whereas the first-order-CSTR (M 1 ) model for the chemical oxygen demand (COD Cr ) and Monod-CSTR (M 3 ) model for the COD Cr and ammonium nitrogen (NH 4 -N) showed a high correlation with the experimental data (R 2  > 0.5). The pollutant removal rates in the case of M 1 were 0.19 m/d (COD Cr ) and those for M 3 were 25.2 g/m 2 ∙d for COD Cr and 2.63 g/m 2 ∙d for NH 4 -N. By applying a multi-variable linear regression method, the optimal empirical models were established for predicting the final effluent concentration of five days' biochemical oxygen demand (BOD 5 ) and NH 4 -N. In general, the hydraulic loading rate was considered an important variable having a high value of relative importance, which appeared in all the optimal predictive models. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. Antimicrobial strength increases with group size: implications for social evolution.

    PubMed

    Turnbull, Christine; Hoggard, Stephen; Gillings, Michael; Palmer, Chris; Stow, Adam; Beattie, Doug; Briscoe, David; Smith, Shannon; Wilson, Peter; Beattie, Andrew

    2011-04-23

    We hypothesize that aggregations of animals are likely to attract pathogenic micro-organisms and that this is especially the case for semisocial and eusocial insects where selection ultimately led to group sizes in the thousands or even millions, attracting the epithet 'superorganism'. Here, we analyse antimicrobial strength, per individual, in eight thrips species (Insecta: Thysanoptera) that present increasing innate group sizes and show that species with the largest group size (100-700) had the strongest antimicrobials, those with smaller groups (10-80) had lower antimicrobial activity, while solitary species showed none. Species with large innate group sizes showed strong antimicrobial activity while the semisocial species showed no activity until group size increased sufficiently to make activity detectable. The eusocial species behaved in a similar way, with detectable activity appearing once group size exceeded 120. These analyses show that antimicrobial strength is determined by innate group size. This suggests that the evolution of sociality that, by definition, increases group size, may have had particular requirements for defences against microbial pathogens. Thus, increase in group size, accompanied by increased antibiotic strength, may have been a critical factor determining the 'point of no return', early in the evolution of social insects, beyond which the evolution of social anatomical and morphological traits was irreversible. Our data suggest that traits that increase group size in general are accompanied by increased antimicrobial strength and that this was critical for transitions from solitary to social and eusocial organization.

  19. Continuous exposure to the deterrents cis-jasmone and methyl jasmonate does not alter the behavioural responses of Frankliniella occidentalis

    PubMed Central

    Egger, Barbara; Spangl, Bernhard; Koschier, Elisabeth Helene

    2016-01-01

    Behavioural responses of Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), a generalist, cell sap-feeding insect species with piercing-sucking mouthparts, after continuous exposure to two deterrent secondary plant compounds are investigated. We compared in choice assays on bean leaf discs, the settling, feeding, and oviposition preferences of F. occidentalis females that had no experience with the two fatty acid derivatives methyl jasmonate and cis-jasmone before testing (naïve thrips) vs. females that had been exposed to the deterrent compounds before testing (experienced thrips). The thrips were exposed to the deterrents at low or high concentrations for varied time periods and subsequently tested on bean leaf discs treated with the respective deterrent at either a low or a high concentration. Frankliniella occidentalis females avoided settling on the deterrent-treated bean leaf discs for an observation period of 6 h, independent of their previous experience. Our results demonstrate that feeding and oviposition deterrence of the jasmonates to the thrips were not altered by continuous exposure of the thrips to the jasmonates. Habituation was not induced, neither by exposure to the low concentration of the deterrents nor by exposure to the high concentration. These results indicate that the risk of habituation to two volatile deterrent compounds after repeated exposure is not evident in F. occidentalis. This makes the two compounds potential candidates to be integrated in pest management strategies. PMID:26726263

  20. An Ecoinformatics Approach to Field-Scale Evaluation of Insecticide Effects in California Citrus: Are Citrus Thrips and Citrus Red Mite Induced Pests?

    PubMed

    Livingston, George; Hack, Lindsey; Steinmann, Kimberly P; Grafton-Cardwell, Elizabeth E; Rosenheim, Jay A

    2018-05-28

    Experimental approaches to studying the consequences of pesticide use, including impacts on beneficial insects, are vital; however, they can be limited in scale and realism. We show that an ecoinformatics approach that leverages existing data on pesticides, pests, and beneficials across multiple fields can provide complementary insights. We do this using a multi-year dataset (2002-2013) on pesticide applications and density estimates of two pests, citrus thrips (Scirtothrips citri (Moulton [Thysanoptera: Thripidae])) and citrus red mites (Panonychus citri McGregor [Acari: Tetranychidae]), and a natural enemy (Euseius spp. predatory mites) collected from citrus groves in the San Joaquin Valley of California. Using correlative analyses, we investigated the long-term consequences of pesticide use on S. citri and P. citri population densities to evaluate the hypothesis that the pest status of these species is largely due to the disruption of natural biological control-i.e., these are induced pests. We also evaluated short-term pesticide efficacy (suppression of citrus thrips and citrus red mite populations immediately post-application) and asked if it was correlated with the suppression of Euseius predator populations. Although the short-term efficacy of different pesticides varied significantly, our dataset does not suggest that the use of citrus pesticides suppressed Euseius densities or worsened pest problems. We also find that there is no general trade-off between pesticide efficacy and pesticide risk to Eusieus, such that highly effective and minimally disruptive compounds were available to citrus growers during the studied time period.

  1. Analysis of expressed sequence tags for Frankliniella occidentalis, the western flower thrips.

    PubMed

    Rotenberg, D; Whitfield, A E

    2010-08-01

    Thrips are members of the insect order Thysanoptera and Frankliniella occidentalis (the western flower thrips) is the most economically important pest within this order. F. occidentalis is both a direct pest of crops and an efficient vector of plant viruses, including Tomato spotted wilt virus (TSWV). Despite the world-wide importance of thrips in agriculture, there is little knowledge of the F. occidentalis genome or gene functions at this time. A normalized cDNA library was constructed from first instar thrips and 13 839 expressed sequence tags (ESTs) were obtained. Our EST data assembled into 894 contigs and 11 806 singletons (12 700 nonredundant sequences). We found that 31% of these sequences had significant similarity (E< or = 10(-10)) to protein sequences in the National Center for Biotechnology Information nonredundant (nr) protein database, and 25% were functionally annotated using Blast 2GO. We identified 74 sequences with putative homology to proteins associated with insect innate immunity. Sixteen sequences had significant similarity to proteins associated with small RNA-mediated gene silencing pathways (RNA interference; RNAi), including the antiviral pathway (short interfering RNA-mediated pathway). Our EST collection provides new sequence resources for characterizing gene functions in F. occidentalis and other thrips species with regards to vital biological processes, studying the mechanism of interactions with the viruses harboured and transmitted by the vector, and identifying new insect gene-centred targets for plant disease and insect control.

  2. Characterization of bacterial symbionts in Frankliniella occidentalis (Pergande), Western flower thrips.

    PubMed

    Chanbusarakum, Lisa; Ullman, Diane

    2008-11-01

    Many insects have associations with bacteria, although it is often difficult to determine the intricacies of the relationships. In one such case, facultative bacteria have been discovered in a major crop pest and virus vector, the Western flower thrips (WFT), Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). Several bacterial isolates have been studied in Netherlands greenhouse thrips populations, with molecular data indicating that these bacteria were similar to Escherichia coli, although biochemical properties suggested these microbes might actually be most similar to plant pathogenic bacteria in the genus Erwinia. We focused on the bacterial flora of the Hawaiian Islands thrips population where these gut bacteria were first reported in 1989. We also analyzed a German population and a 1965 California population preserved in ethanol. Culture and culture-independent techniques revealed a consistent microflora that was similar to the Netherlands isolates studied. The similarity among thrips microbes from multiple populations and environments suggested these bacteria and their hosts share a widespread association. Molecular phylogeny based on the 16S rRNA gene and biochemical analysis of thrips bacteria suggested two distinctive groups of microbes are present in thrips. Phylogenetic analysis also revealed support for one thrips bacterial group having a shared ancestry with Erwinia, whereas the second group of thrips bacteria fell out with E. coli, but without support. Although species-specific relationships were indeterminable due to the conservative nature of 16S, there is strong indication that thrips symbionts belong to two different genera and originated from environmental microbes.

  3. The mitochondrial genome of Frankliniella intonsa: insights into the evolution of mitochondrial genomes at lower taxonomic levels in Thysanoptera.

    PubMed

    Yan, Dankan; Tang, Yunxia; Hu, Min; Liu, Fengquan; Zhang, Dongfang; Fan, Jiaqin

    2014-10-01

    Thrips is an ideal group for studying the evolution of mitochondrial (mt) genomes in the genus and family due to independent rearrangements within this order. The complete sequence of the mitochondrial DNA (mtDNA) of the flower thrips Frankliniella intonsa has been completed and annotated in this study. The circular genome is 15,215bp in length with an A+T content of 75.9% and contains the typical 37 genes and it has triplicate putative control regions. Nucleotide composition is A+T biased, and the majority of the protein-coding genes present opposite CG skew which is reflected by the nucleotide composition, codon and amino acid usage. Although the known thrips have massive gene rearrangements, it showed no reversal of strand asymmetry. Gene rearrangements have been found in the lower taxonomic levels of thrips. Three tRNA genes were translocated in the genus Frankliniella and eight tRNA genes in the family Thripidae. Although the gene arrangements of mt genomes of all three thrips species differ massively from the ancestral insect, they are all very similar to each other, indicating that there was a large rearrangement somewhere before the most recent common ancestor of these three species and very little genomic evolution or rearrangements after then. The extremely similar sequences among the CRs suggest that they are ongoing concerted evolution. Analyses of the up and downstream sequence of CRs reveal that the CR2 is actually the ancestral CR. The three CRs are in the same spot in each of the three thrips mt genomes which have the identical inverted genes. These characteristics might be obtained from the most recent common ancestor of this three thrips. Above observations suggest that the mt genomes of the three thrips keep a single massive rearrangement from the common ancestor and have low evolutionary rates among them. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Insecticide Rotation Programs with Entomopathogenic Organisms for Suppression of Western Flower Thrips (Thysanoptera: Thripidae) Adult Populations under Greenhouse Conditions.

    PubMed

    Kivett, Jessica M; Cloyd, Raymond A; Bello, Nora M

    2015-08-01

    Western flower thrips, Frankliniella occidentalis (Pergande), is one of the most destructive insect pests of greenhouse production systems with the ability to develop resistance to a wide variety of insecticides. A common resistance management strategy is rotating insecticides with different modes of action. By incorporating entomopathogenic organisms (fungi and bacteria), which have discrete modes of action compared to standard insecticides, greenhouse producers may preserve the effectiveness of insecticides used for suppression of western flower thrips populations. The objective of this study was to determine how different rotation programs that include entomopathogenic organisms (Beauveria bassiana, Isaria fumosoroseus, Metarhizium anisopliae, and Chromobacterium subtsugae) and commonly used standard insecticides (spinosad, chlorfenapyr, abamectin, and pyridalyl) may impact the population dynamics of western flower thrips adult populations by means of suppression. Eight-week rotation programs were applied to chrysanthemum, Dendranthema x morifolium plants and weekly counts of western flower thrips adults captured on yellow sticky cards were recorded as a means to evaluate the impact of the rotation programs. A final quality assessment of damage caused by western flower thrips feeding on foliage and flowers was also recorded. Furthermore, a cost comparison of each rotation program was conducted. Overall, insecticide rotation programs that incorporated entomopathogenic organisms were not significantly different than the standard insecticide rotation programs without entomopathogenic organisms in suppressing western flower thrips adult populations. However, there were no significant differences among any of the rotation programs compared to the water control. Moreover, there was no differential effect of the rotation programs on foliage and flower quality. Cost savings of up to 34% (in US dollars) are possible when including entomopathogenic organisms in the rotation program. Therefore, by incorporating entomopathogenic organisms into insecticide rotation programs, greenhouse producers can decrease costs without affecting suppression, as well as diminish selection pressure on western flower thrips adult populations, which may avoid or delay resistance development. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  5. Semi-commercial ultralow oxygen treatment for control of western flower thrips, frankliniella occidentalis (thysanoptera: thripidae), on harvested iceberg lettuce.

    USDA-ARS?s Scientific Manuscript database

    Pallet scale two day ultralow oxygen (ULO) treatment with 30 ppm oxygen at 10°C ambient temperature was conducted on seven cultivars of vacuum cooled iceberg lettuce which had been stored for 1, 3, 4, and 6 days to develop a safe and effective treatment for control of western flower thrips, Franklin...

  6. The Influence of Elevated CO2 Concentration on the Fitness Traits of Frankliniella occidentalis and Frankliniella intonsa (Thysanoptera: Thripidae).

    PubMed

    ShuQi, He; Ying, Lin; Lei, Qian; ZhiHua, Li; Chao, Xi; Lu, Yang; FuRong, Gui

    2017-06-01

    Development and fecundity were investigated in an invasive alien thrips species, Frankliniella occidentalis (Pergande), and a related native species, Frankliniella intonsa (Trybom), under high CO2 concentration. Results show that the two thrips species reacted differently toward elevated CO2 concentration. Developmental duration decreased significantly (11.93%) in F. occidentalis at the CO2 concentration of 800 µl/liter; survival rate of all stages also significantly increased (e.g., survival rate of first instar increased 17.80%), adult longevity of both female and male extended (e.g., female increased 2.02 d on average), and both fecundity and daily eggs laid per female were higher at a CO2 concentration of 800 µl/liter than at 400 µl/liter. Developmental duration of F. intonsa decreased, insignificantly, at a CO2 concentration of 800 µl/liter. Unlike F. occidentalis, survival rate of F. intonsa declined considerably at higher CO2 concentration level (e.g., survival rate of first instar decreased 19.70%), adult longevity of both female and male curtailed (e.g., female reduced 3.82 d on average), and both fecundity and daily eggs laid per female were reduced to 24.86 and 0.83, respectively, indicating that there exist significant differences between the two CO2 levels. Results suggest that the population fitness of invasive thrips species might be enhanced with increase in CO2 concentration, and accordingly change the local thrips population composition with their invasion. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  7. [Thermal requirements and estimate of the annual number of generations of Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) on strawberry crop].

    PubMed

    Nondillo, Aline; Redaelli, Luiza R; Botton, Marcos; Pinent, Silvia M J; Gitz, Rogério

    2008-01-01

    Frankliniella occidentalis (Pergande) is one of the major strawberry pests in southern Brazil. The insect causes russeting and wither in flowers and fruits reducing commercial value. In this work, the thermal requirements of the eggs, larvae and pupae of F. occidentalis were estimated. Thrips development was studied in folioles of strawberry plants at six constant temperatures (16, 19, 22, 25, 28 and 31 degrees C) in controlled conditions (70 +/- 10% R.H. and 12:12 L:D). The number of annual generations of F. occidentalis was estimated for six strawberry production regions of Rio Grande do Sul State based on its thermal requirements. Developmental time of each F. occidentalis stages was proportional to the temperature increase. The best development rate was obtained when insects were reared at 25 masculineC and 28 masculineC. The lower threshold and the thermal requirements for the egg to adult stage were 9.9 masculineC and 211.9 degree-days, respectively. Considering the thermal requirements of F. occidentalis, 10.7, 12.6, 13.1, 13.6, 16.5 and 17.9 generations/year were estimated, respectively, for Vacaria, Caxias do Sul, Farroupilha, Pelotas, Porto Alegre and Taquari producing regions located in Rio Grande do Sul State, Brazil.

  8. Starvation period and age affect the response of female Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) to odor and visual cues.

    PubMed

    Davidson, Melanie M; Butler, Ruth C; Teulon, David A J

    2006-07-01

    The effects of starvation or age on the walking or flying response of female Frankliniella occidentalis to visual and/or odor cues in two types of olfactometer were examined in the laboratory. The response of walking thrips starved for 0, 1, 4, or 24h to an odor cue (1microl of 10% p-anisaldehyde) was examined in a Y-tube olfactometer. The take-off and landing response of thrips (unknown age) starved for 0, 1, 4, 24, 48 or 72h, or of thrips of different ages (2-3 days or 10-13 days post-adult emergence) starved for 24h, to a visual cue (98 cm(2) yellow sticky trap) and/or an odor cue (0.5 or 1.0 ml p-anisaldehyde) was examined in a wind tunnel. More thrips walked up the odor-laden arm in the Y-tube when starved for at least 4h (76%) than satiated thrips (58.7%) or those starved for 1h (62.7%, P<0.05). In the wind tunnel experiments the percentage of thrips to fly or land on the sticky trap increased between satiated thrips (7.3% to fly, 3.3% on trap) and those starved for 4h (81.2% to fly, 29% on trap) and decreased between thrips starved for 48 (74.5% to fly, 23% on trap) and 72 h (56.5% to fly, 15.5% on trap, P<0.05). Fewer younger thrips (38.8%) landed on a sticky trap containing a yellow visual cue of, those that flew, than older thrips (70.4%, P<0.05), although a similar percentage of thrips flew regardless of age or type of cue present in the wind tunnel (average 44%, P>0.05).

  9. Identification of an antibacterial compound, benzylideneacetone, from Xenorhabdus nematophila against major plant-pathogenic bacteria.

    PubMed

    Ji, Dongjin; Yi, Youngkeun; Kang, Ga-Hwa; Choi, Yong-Hwa; Kim, Pankyung; Baek, Nam-In; Kim, Yonggyun

    2004-10-15

    An entomopathogenic bacterium, Xenorhabdus nematophila, is known to have potent antibiotic activities to maintain monoxenic condition in its insect host for effective pathogenesis and ultimately for optimal development of its nematode symbiont, Steinernema carpocapsae. In this study we assess its antibacterial activity against plant-pathogenic bacteria and identify its unknown antibiotics. The bacterial culture broth had significant antibacterial activity that increased with development of the bacteria and reached its maximum at the stationary growth phase. The antibiotic activities were significant against five plant-pathogenic bacterial strains: Agrobacterium vitis, Pectobacterium carotovorum subsp. atrosepticum, P. carotovorum subsp. carotovorum, Pseudomonas syringae pv. tabaci, and Ralstonia solanacearum. The antibacterial factors were extracted with butanol and fractionated using column chromatography with the eluents of different hydrophobic intensities. Two active antibacterial subfractions were purified, and the higher active fraction was further fractionated and identified as a single compound of benzylideneacetone (trans-4-phenyl-3-buten-2-one). With heat stability, the synthetic compound showed equivalent antibiotic activity and spectrum to the purified compound. This study reports a new antibiotic compound synthesized by X. nematophila, which is a monoterpenoid compound and active against some Gram-negative bacteria.

  10. The Facultative Symbiont Rickettsia Protects an Invasive Whitefly against Entomopathogenic Pseudomonas syringae Strains

    PubMed Central

    Hunter, Martha S.; Baltrus, David A.

    2014-01-01

    Facultative endosymbionts can benefit insect hosts in a variety of ways, including context-dependent roles, such as providing defense against pathogens. The role of some symbionts in defense may be overlooked, however, when pathogen infection is transient, sporadic, or asymptomatic. The facultative endosymbiont Rickettsia increases the fitness of the sweet potato whitefly (Bemisia tabaci) in some populations through mechanisms that are not yet understood. In this study, we investigated the role of Rickettsia in mediating the interaction between the sweet potato whitefly and Pseudomonas syringae, a common environmental bacterium, some strains of which are pathogenic to aphids. Our results show that P. syringae multiplies within whiteflies, leading to host death, and that whiteflies infected with Rickettsia show a decreased rate of death due to P. syringae. Experiments using plants coated with P. syringae confirmed that whiteflies can acquire the bacteria at a low rate while feeding, leading to increased mortality, particularly when the whiteflies are not infected with Rickettsia. These results suggest that P. syringae may affect whitefly populations in nature and that Rickettsia can ameliorate this effect. This study highlights the possible importance of interactions among opportunistic environmental pathogens and endosymbionts of insects. PMID:25217020

  11. Recessive Resistance Derived from Tomato cv. Tyking-Limits Drastically the Spread of Tomato Yellow Leaf Curl Virus

    PubMed Central

    Pereira-Carvalho, Rita C.; Díaz-Pendón, Juan A.; Fonseca, Maria Esther N.; Boiteux, Leonardo S.; Fernández-Muñoz, Rafael; Moriones, Enrique; Resende, Renato O.

    2015-01-01

    The tomato yellow leaf curl disease (TYLCD) causes severe damage to tomato (Solanum lycopersicum L.) crops throughout tropical and subtropical regions of the world. TYLCD is associated with a complex of single-stranded circular DNA plant viruses of the genus Begomovirus (family Geminiviridae) transmitted by the whitefy Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae). The tomato inbred line TX 468-RG is a source of monogenic recessive resistance to begomoviruses derived from the hybrid cv. Tyking F1. A detailed analysis of this germplasm source against tomato yellow leaf curl virus-Israel (TYLCV-IL), a widespread TYLCD-associated virus, showed a significant restriction to systemic virus accumulation even under continuous virus supply. The resistance was effective in limiting the onset of TYLCV-IL in tomato, as significantly lower primary spread of the virus occurred in resistant plants. Also, even if a limited number of resistant plants could result infected, they were less efficient virus sources for secondary spread owing to the impaired TYLCV-IL accumulation. Therefore, the incorporation of this resistance into breeding programs might help TYLCD management by drastically limiting TYLCV-IL spread. PMID:26008699

  12. Emamectin, a novel insecticide for controlling field crop pests.

    PubMed

    Ishaaya, Isaac; Kontsedalov, Svetlana; Horowitz, A Rami

    2002-11-01

    Emamectin is a macrocyclic lactone insecticide with low toxicity to non-target organisms and the environment, and is considered an important component in pest-management programmes for controlling field crop pests. It is a powerful compound for controlling the cotton bollworm Helicoverpa armigera (Hübner). A spray concentration of 25 mg AI litre-1 in a cotton field resulted in over 90% suppression of H armigera larvae up to day 28 after treatment, while similar mortality of the Egyptian cotton leafworm Spodoptera littoralis Boisduval, under the same conditions, was maintained for 3 days only. Emamectin is a potent compound for controlling the western flower thrips Frankliniella occidentalis (Pergande) under both laboratory and field conditions and its activity on adults was over 10-fold greater than that of abamectin. Spray concentrations of 10 and 50 mg AI litre-1 in Ageratum houstonianum Mill flowers resulted in total suppression of adults up to day 11 and of larvae up to day 20 after treatment. Under standard laboratory conditions, emamectin exhibits a considerable activity on the whitefly Bemisia tabaci (Gennadius) and the leafminer Liriomyza huidobrensis (Blanchard). Further studies are required to evaluate its potential activity on the latter pests under field conditions.

  13. Function of Oxidative Cross-Linking of Cell Wall Structural Proteins in Plant Disease Resistance.

    PubMed

    Brisson, L. F.; Tenhaken, R.; Lamb, C.

    1994-12-01

    Elicitation of soybean cells causes a rapid insolubilization of two cell wall structural proteins, p33 and p100. Likewise, a short elicitation of 30 min rendered cell walls more refractory to enzyme digestion as assayed by the yield of protoplasts released. This effect could be ascribed to protein cross-linking because of its insensitivity to inhibitors of transcription (actinomycin D) and translation (cycloheximide) and its induction by exogenous H2O2. Moreover, the induced loss of protoplasts could be prevented by preincubation with DTT, which also blocks peroxidase-mediated oxidative cross-linking. The operation of protein insolubilization in plant defense was also demonstrated by its occurrence in the incompatible interaction but not in the compatible interaction between soybean and Pseudomonas syringae pv glycinea. Likewise, protein insolubilization was observed in bean during non-host hypersensitive resistance to the tobacco pathogen P. s. pv tabaci mediated by the hypersensitive resistance and pathogenicity (Hrp) gene cluster. Our data strongly suggest that rapid protein insolubilization leads to a strengthened cell wall, and this mechanism functions as a rapid defense in the initial stages of the hypersensitive response prior to deployment of transcription-dependent defenses.

  14. Virulence Factors of Geminivirus Interact with MYC2 to Subvert Plant Resistance and Promote Vector Performance[C][W

    PubMed Central

    Li, Ran; Weldegergis, Berhane T.; Li, Jie; Jung, Choonkyun; Qu, Jing; Sun, Yanwei; Qian, Hongmei; Tee, ChuanSia; van Loon, Joop J.A.; Dicke, Marcel; Chua, Nam-Hai; Liu, Shu-Sheng

    2014-01-01

    A pathogen may cause infected plants to promote the performance of its transmitting vector, which accelerates the spread of the pathogen. This positive effect of a pathogen on its vector via their shared host plant is termed indirect mutualism. For example, terpene biosynthesis is suppressed in begomovirus-infected plants, leading to reduced plant resistance and enhanced performance of the whiteflies (Bemisia tabaci) that transmit these viruses. Although begomovirus-whitefly mutualism has been known, the underlying mechanism is still elusive. Here, we identified βC1 of Tomato yellow leaf curl China virus, a monopartite begomovirus, as the viral genetic factor that suppresses plant terpene biosynthesis. βC1 directly interacts with the basic helix-loop-helix transcription factor MYC2 to compromise the activation of MYC2-regulated terpene synthase genes, thereby reducing whitefly resistance. MYC2 associates with the bipartite begomoviral protein BV1, suggesting that MYC2 is an evolutionarily conserved target of begomoviruses for the suppression of terpene-based resistance and the promotion of vector performance. Our findings describe how this viral pathogen regulates host plant metabolism to establish mutualism with its insect vector. PMID:25490915

  15. Synthesis and biological activity of a new class of insecticides: the N-(5-aryl-1,3,4-thiadiazol-2-yl)amides.

    PubMed

    Eckelbarger, Joseph D; Parker, Marshall H; Yap, Maurice Ch; Buysse, Ann M; Babcock, Jonathan M; Hunter, Ricky; Adelfinskaya, Yelena; Samaritoni, Jack G; Garizi, Negar; Trullinger, Tony K

    2017-04-01

    Optimization studies on a high-throughput screening (HTS) hit led to the discovery of a series of N-(6-arylpyridazin-3-yl)amides with insecticidal activity. It was hypothesized that the isosteric replacement of the pyridazine ring with a 1,3,4-thiadiazole ring could lead to more potent biological activity and/or a broader sap-feeding pest spectrum. The resulting N-(5-aryl-1,3,4-thiadiazol-2-yl)amides were explored as a new class of insecticides. Several methods for 2-amino-1,3,4-thiadiazole synthesis were used for the preparation of key synthetic intermediates. Subsequent coupling to variously substituted carboxylic acid building blocks furnished the final targets, which were tested for insecticidal activity against susceptible strains of Aphis gossypii (Glover) (cotton aphid), Myzus persicae (Sulzer) (green peach aphid) and Bemisia tabaci (Gennadius) (sweetpotato whitefly). Structure-activity relationship (SAR) studies on both the amide tail and the aryl A-ring of novel N-(5-aryl-1,3,4-thiadiazol-2-yl)amides led to a new class of insecticidal molecules active against sap-feeding insect pests. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  16. Insect stings to change gear for healthy plant: Improving maize drought tolerance by whitefly infestation.

    PubMed

    Park, Yong-Soon; Ryu, Choong-Min

    2016-05-03

    Since plants first appeared about 1.1 billion years ago, they have been faced with biotic and abiotic stresses in their environment. To overcome these stresses, plants developed defense strategies. Accumulating evidence suggests that the whitefly [Bemisia tabaci (Genn.)] affects the regulation of plant defenses and physiology. A recent study demonstrates that aboveground whitefly infestation positively modulates root biomass and anthocyanin pigmentation on brace roots of maize plants (Zea mays L.). In agreement with these observations, indole-3-acetic acid (IAA) and jasmonic acid (JA) contents and the expression of IAA- and JA-related genes are higher in whitefly-infested maize plants than in non-infected control plants. Interestingly, the fresh weight of whitefly-infested maize plants is approximately 20% higher than in non-infected control plants under water stress conditions. Further investigation has revealed that hydrogen peroxide (H2O2) accumulates in whitefly-infested maize plants after water stoppage. Taken together, these results suggest that activation of phytohormones- (i.e., IAA and JA) and H2O2-mediated maize signaling pathways triggered by aboveground whitefly infestation promotes drought resistance. They also provide an insight into how inter-kingdom interactions can improve drought tolerance in plants.

  17. Transgenic plants expressing the AaIT/GNA fusion protein show increased resistance and toxicity to both chewing and sucking pests.

    PubMed

    Liu, Shu-Min; Li, Jie; Zhu, Jin-Qi; Wang, Xiao-Wei; Wang, Cheng-Shu; Liu, Shu-Sheng; Chen, Xue-Xin; Li, Sheng

    2016-04-01

    The adoption of pest-resistant transgenic plants to reduce yield losses and decrease pesticide use has been successful. To achieve the goal of controlling both chewing and sucking pests in a given transgenic plant, we generated transgenic tobacco, Arabidopsis, and rice plants expressing the fusion protein, AaIT/GNA, in which an insecticidal scorpion venom neurotoxin (Androctonus australis toxin, AaIT) is fused to snowdrop lectin (Galanthus nivalis agglutinin, GNA). Compared with transgenic tobacco and Arabidopsis plants expressing AaIT or GNA, transgenic plants expressing AaIT/GNA exhibited increased resistance and toxicity to one chewing pest, the cotton bollworm, Helicoverpa armigera. Transgenic tobacco and rice plants expressing AaIT/GNA showed increased resistance and toxicity to two sucking pests, the whitefly, Bemisia tabaci, and the rice brown planthopper, Nilaparvata lugens, respectively. Moreover, in the field, transgenic rice plants expressing AaIT/GNA exhibited a significant improvement in grain yield when infested with N. lugens. This study shows that expressing the AaIT/GNA fusion protein in transgenic plants can be a useful approach for controlling pests, particularly sucking pests which are not susceptible to the toxin in Bt crops. © 2015 Institute of Zoology, Chinese Academy of Sciences.

  18. Fungal mitochondrial DNases: effectors with the potential to activate plant defenses in nonhost resistance.

    PubMed

    Hadwiger, Lee A; Polashock, James

    2013-01-01

    Previous reports on the model nonhost resistance interaction between Fusarium solani f. sp. phaseoli and pea endocarp tissue have described the disease resistance-signaling role of a fungal DNase1-like protein. The response resulted in no further growth beyond spore germination. This F. solani f. sp. phaseoli DNase gene, constructed with a pathogenesis-related (PR) gene promoter, when transferred to tobacco, generated resistance against Pseudomonas syringe pv. tabaci. The current analytical/theoretical article proposes similar roles for the additional nuclear and mitochondrial nucleases, the coding regions for which are identified in newly available fungal genome sequences. The amino acid sequence homologies within functional domains are conserved within a wide array of fungi. The potato pathogen Verticillium dahliae nuclease was divergent from that of the saprophyte, yeast; however, the purified DNase from yeast also elicited nonhost defense responses in pea, including pisatin accumulation, PR gene induction, and resistance against a true pea pathogen. The yeast mitochondrial DNase gene (open reading frame) predictably codes for a signal peptide providing the mechanism for secretion. Mitochondrial DNase genes appear to provide an unlimited source of components for developing transgenic resistance in all transformable plants.

  19. Climate Change: Life history adaptation by a global whitefly, Bemisia tabaci, with rising temperature and carbon dioxide

    USDA-ARS?s Scientific Manuscript database

    Introduction: Climate change can have direct and indirect impacts on living organisms. A rise in ambient temperature and elevated carbon dioxide (CO2) concentrations due to global warming may have assorted impacts on arthropods such as altered life cycles, altered reproductive patterns, and change...

  20. Evolution and homoplasy at the Bem6 microsatellite locus in three sweetpotato whitefly (Bemisia tabaci) cryptic species

    USDA-ARS?s Scientific Manuscript database

    The evolution of individual microsatellite loci is often complex and homoplasy is common but often goes undetected. Sequencing alleles at a microsatellite locus can provide a more complete picture of the common evolutionary mechanisms occurring at that locus and can reveal cases of homoplasy. Within...

  1. First report of Bemisia tabaci biotype Q in Costa Rica and detection of viruliferous whiteflies in greenhouses

    USDA-ARS?s Scientific Manuscript database

    Whiteflies are a complex that comprises multiple species and biotypes or races which are capable of affecting crops by phloem feeding, virus transmission and promotion of fungal colonization. The distribution of these pests is worldwide. In Costa Rica, a country located in the tropics, the most prob...

  2. X-ray Irradiation Control of Frankliniella occidentalis and Frankliniella intonsa (Thysanoptera: Thripidae) in the Exportation of Freshly Cut Lily Flowers.

    PubMed

    Koo, Hyun-Na; Yun, Seung-Hwan; Kim, Hyun-Ju; Kim, Hyun Kyung; Kim, Gil-Hah

    2017-04-01

    Lily (Lilium longiflorum Thunb.) is the most representative bulb flower, and it is the third most important flower in the flower industry of South Korea after rose and chrysanthemum. To determine the efficacy of X-ray irradiation for use in quarantine processing, two species of flower thrips (Frankliniella intonsa (Trybom) and Frankliniella occidentalis (Pergande)) were placed in the top, middle, and bottom locations of lily boxes and irradiated with different X-ray doses. After irradiation with an X-ray dose of 150 Gy, the egg hatching of the two flower thrips was completely inhibited at every location in the lily boxes, and the irradiated F. intonsa and F. occidentalis nymphs failed to emerge as adult in every location of the lily boxes. When the adults were irradiated at 150 Gy, the fecundity of the two flower thrips was markedly lower than that of the untreated control groups. The F1 generation failed to hatch at the top and middle locations, whereas the F1 generation of both F. intonsa and F. occidentalis was not suppressed at the bottom locations, even at 200 Gy. However, hatching was perfectly inhibited at 300 Gy of X-ray irradiation. Also, X-rays did not affect the postharvest physiology of cut lilies. Therefore, a minimum dose of 300 Gy is recommended for the control of F. intonsa and F. occidentalis for the exportation of lily. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  3. Tomato plant and leaf age effects on the probing and settling behavior of Frankliniella fusca and Frankliniella occidentalis (Thysanoptera: Thripidae).

    PubMed

    Joost, P Houston; Riley, David G

    2008-02-01

    The effect of tomato, Solanum lycopersicum L., plant and leaf age on the probing and settling behavior of Frankliniella fusca (Hinds) and F. occidentalis (Pergande) was studied using electrical penetration graph technique and whole plant bioassays. Male and female F. fusca probed and ingested more and for longer periods of time on 3- and 4-wk-old plants compared with 6- and 8-wk-old plants. Female F. fusca probed and ingested more frequently than males in the plant age experiment, but not in the leaf age experiment. F. fusca probed and ingested more frequently on 2- and 4-wk-old leaves compared with 1-wk-old leaves. Plant age did not affect the probing frequency or duration of F. occidentalis; however, males probed and ingested longer than females in the plant age experiment and on the oldest leaf in the leaf age experiment. Both thrips species preferred to settle on 3-wk-old plants. F. fusca preferred to settle on 4-wk-old leaves after settling randomly for an hour. F. occidentalis showed no settling preference relative to leaf age. The preference of F. fusca for young plants suggests that this species could attack tomato plants at a very early stage, which is important for understanding its role as a vector in the transmission of Tospovirus in the field.

  4. Natural vegetation cover in the landscape and edge effects: differential responses of insect orders in a fragmented forest.

    PubMed

    González, Ezequiel; Salvo, Adriana; Valladares, Graciela

    2017-10-01

    Human activities have led to global simplification of ecosystems, among which Neotropical dry forests are some of the most threatened. Habitat loss as well as edge effects may affect insect communities. Here, we analyzed insects sampled with pan traps in 9 landscapes (at 5 scales, in 100-500 m diameter circles) comprising cultivated fields and Chaco Serrano forests, at overall community and taxonomic order level. In total 7043 specimens and 456 species of hexapods were captured, with abundance and richness being directly related to forest cover at 500 m and higher at edges in comparison with forest interior. Community composition also varied with forest cover and edge/interior location. Different responses were detected among the 8 dominant orders. Collembola, Hemiptera, and Orthoptera richness and/or abundance were positively related to forest cover at the larger scale, while Thysanoptera abundance increased with forest cover only at the edge. Hymenoptera abundance and richness were negatively related to forest cover at 100 m. Coleoptera, Diptera, and Hymenoptera were more diverse and abundant at the forest edge. The generally negative influence of forest loss on insect communities could have functional consequences for both natural and cultivated systems, and highlights the relevance of forest conservation. Higher diversity at the edges could result from the simultaneous presence of forest and matrix species, although "resource mapping" might be involved for orders that were richer and more abundant at edges. Adjacent crops could benefit from forest proximity since natural enemies and pollinators are well represented in the orders showing positive edge effects. © 2016 Institute of Zoology, Chinese Academy of Sciences.

  5. Can Mass Trapping Reduce Thrips Damage and Is It Economically Viable? Management of the Western Flower Thrips in Strawberry

    PubMed Central

    Sampson, Clare; Kirk, William D. J.

    2013-01-01

    The western flower thrips Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) is a cosmopolitan, polyphagous insect pest that causes bronzing to fruit of strawberry (Fragaria x ananassa). The main aim of this study was to test whether mass trapping could reduce damage and to predict whether this approach would be economically viable. In semi-protected strawberry crops, mass trapping of F. occidentalis using blue sticky roller traps reduced adult thrips numbers per flower by 61% and fruit bronzing by 55%. The addition of the F. occidentalis aggregation pheromone, neryl (S)-2-methylbutanoate, to the traps doubled the trap catch, reduced adult thrips numbers per flower by 73% and fruit bronzing by 68%. The factors affecting trapping efficiency through the season are discussed. Damage that would result in downgrading of fruit to a cheaper price occurred when bronzing affected about 10% of the red fruit surface. Cost-benefit analysis using this threshold showed that mass trapping of thrips using blue sticky roller traps can be cost-effective in high-value crops. The addition of blue sticky roller traps to an integrated pest management programme maintained thrips numbers below the damage threshold and increased grower returns by a conservative estimate of £2.2k per hectare. Further work is required to develop the F. occidentalis aggregation pheromone for mass trapping and to determine the best timing for trap deployment. Mass trapping of thrips is likely to be cost-effective in other countries and other high-value crops affected by F. occidentalis damage, such as cucumber and cut flowers. PMID:24282554

  6. Estimating the Effectiveness of Imidacloprid When Used to Suppress Transmission of Tomato spotted wilt orthotospovirus in Commercial Agriculture.

    PubMed

    Chappell, Thomas M; Kennedy, George G

    2018-06-21

    Imidacloprid is widely used to manage tomato spotted wilt disease (TSW) in tobacco, tomato, and pepper, caused by Tomato spotted wilt orthotospovirus (TSWV) and spread by the tobacco thrips, Frankliniella fusca Hinds (Thysanoptera: Thripidae). Imidacloprid suppresses transmission of TSWV by reducing probing and feeding by adult thrips on treated plants, thereby reducing the probability of transmission by infectious thrips. Because imidacloprid does not reduce probing and feeding on treated plants to zero, the reduction in transmission probability per viruliferous thrips can be offset by an increase in the number of viruliferous thrips challenging treated plants. A composite of these effects which we call 'pathogen pressure' experienced by plants is a function of thrips population size, the proportion of those thrips that are viruliferous, and the probability that viruliferous thrips successfully inoculate plants. To better understand the relationship between imidacloprid's effect on virus transmission, pathogen pressure, and TSW incidence in tobacco, we modeled TSW incidence as a function of the two most important variables affecting components of pathogen pressure, temperature, and precipitation, and the dependence of imidacloprid's effect on pathogen pressure. A model incorporating imidacloprid's effect as a reduction in pathogen pressure was found to be more descriptive than models incorporating the effect as a reduction in TSW incidence. Results reveal maximum proportional reduction in TSW incidence resulting from imidacloprid use is associated with minimal potential TSW incidence. As pathogen pressure increases, potential TSW incidence approaches 100%, and the benefits of imidacloprid use are highest at intermediate levels of pathogen pressure.

  7. Ontogenetic shifts in intraguild predation on thrips by phytoseiid mites: the relevance of body size and diet specialization.

    PubMed

    Walzer, A; Paulus, H F; Schausberger, P

    2004-12-01

    In greenhouse agroecosystems, a guild of spider mite predators may consist of the oligophagous predatory mite Phytoseiulus persimilis Athias-Henriot, the polyphagous predatory mite Neoseiulus californicus McGregor (both Acari: Phytoseiidae) and the primarily herbivorous but facultatively predatory western flower thrips Frankliniella occidentalis Pergande (Thysanoptera: Thripidae). Diet-specialization and the predator body size relative to prey are crucial factors in predation on F. occidentalis by P. persimilis and N. californicus. Here, it was tested whether the relevance of these factors changes during predator ontogeny. First, the predator (protonymphs and adult females of P. persimilis and N. californicus): prey (F. occidentalis first instars) body size ratios were measured. Second, the aggressiveness of P. persimilis and N. californicus towards F. occidentalis was assessed. Third, survival, development and oviposition of P. persimilis and N. californicus with F. occidentalis prey was determined. The body size ranking was P. persimilis females > N. californicus females > P. persimilis protonymphs > N. californicus protonymphs. Neoseiulus californicus females were the most aggressive predators, followed by highly aggressive N. californicus protonymphs and moderately aggressive P. persimilis protonymphs. Phytoseiulus persimilis females did not attack thrips. Frankliniella occidentalis larvae are an alternative prey for juvenile N. californicus and P. persimilis, enabling them to reach adulthood. Females of N. californicus but not P. persimilis sustained egg production with thrips prey. Within the guild studied here, N. californicus females are the most harmful predators for F. occidentalis larvae, followed by N. californicus and P. persimilis juveniles. Phytoseiulus persimilis females are harmless to F. occidentalis.

  8. Horizontal transmission of the insect symbiont Rickettsia is plant-mediated

    PubMed Central

    Caspi-Fluger, Ayelet; Inbar, Moshe; Mozes-Daube, Netta; Katzir, Nurit; Portnoy, Vitaly; Belausov, Eduard; Hunter, Martha S.; Zchori-Fein, Einat

    2012-01-01

    Bacteria in the genus Rickettsia, best known as vertebrate pathogens vectored by blood-feeding arthropods, can also be found in phytophagous insects. The presence of closely related bacterial symbionts in evolutionarily distant arthropod hosts presupposes a means of horizontal transmission, but no mechanism for this transmission has been described. Using a combination of experiments with live insects, molecular analyses and microscopy, we found that Rickettsia were transferred from an insect host (the whitefly Bemisia tabaci) to a plant, moved inside the phloem, and could be acquired by other whiteflies. In one experiment, Rickettsia was transferred from the whitefly host to leaves of cotton, basil and black nightshade, where the bacteria were restricted to the phloem cells of the plant. In another experiment, Rickettsia-free adult whiteflies, physically segregated but sharing a cotton leaf with Rickettsia-plus individuals, acquired the Rickettsia at a high rate. Plants can serve as a reservoir for horizontal transmission of Rickettsia, a mechanism which may explain the occurrence of phylogenetically similar symbionts among unrelated phytophagous insect species. This plant-mediated transmission route may also exist in other insect–symbiont systems and, since symbionts may play a critical role in the ecology and evolution of their hosts, serve as an immediate and powerful tool for accelerated evolution. PMID:22113034

  9. Molecular cloning of a defense-response-related cytochrome P450 gene from tobacco.

    PubMed

    Takemoto, D; Hayashi, M; Doke, N; Nishimura, M; Kawakita, K

    1999-12-01

    Plant defenses against pathogen attack involve a series of inducible responses that contribute to resistance. Tobacco leaves injected with HWC (hyphal wall components prepared from Phytophthora infestans) elicitor showed typical defense responses, including the induction of localized necrosis and the accumulation of pathogenesis-related proteins. In order to elucidate the molecular mechanisms by which plant defense systems are activated, we screened tobacco plants for genes differentially expressed in response to HWC. We performed differential screening by RT-PCR with random primers and obtained PCR products specific to HWC-treated leaf RNA. Northern hybridization using the PCR products as probes confirmed that one transcript was actually induced by HWC treatment. As the deduced amino acid sequence of this clone showed the highest degree of similarity to elicitor-induced soybean cytochrome P450 CYP82A4, it was designated CYP82E1. The expression of CYP82E1 was strongly induced in tobacco by the soybean pathogen Pseudomonas syringae pv. glycinea (nonpathogenic on tobacco), but it was activated only slightly and in a delayed fashion by the tobacco pathogen P. syringae pv. tabaci (pathogenic on tobacco), implying that the product of CYP82E1 may be involved in disease resistance in tobacco.

  10. Arabidopsis Heterotrimeric G-Proteins Play a Critical Role in Host and Nonhost Resistance against Pseudomonas syringae Pathogens

    PubMed Central

    Lee, Seonghee; Rojas, Clemencia M.; Ishiga, Yasuhiro; Pandey, Sona; Mysore, Kirankumar S.

    2013-01-01

    Heterotrimeric G-proteins have been proposed to be involved in many aspects of plant disease resistance but their precise role in mediating nonhost disease resistance is not well understood. We evaluated the roles of specific subunits of heterotrimeric G-proteins using knock-out mutants of Arabidopsis Gα, Gβ and Gγ subunits in response to host and nonhost Pseudomonas pathogens. Plants lacking functional Gα, Gβ and Gγ1Gγ2 proteins displayed enhanced bacterial growth and disease susceptibility in response to host and nonhost pathogens. Mutations of single Gγ subunits Gγ1, Gγ2 and Gγ3 did not alter bacterial disease resistance. Some specificity of subunit usage was observed when comparing host pathogen versus nonhost pathogen. Overexpression of both Gα and Gβ led to reduced bacterial multiplication of nonhost pathogen P. syringae pv. tabaci whereas overexpression of Gβ, but not of Gα, resulted in reduced bacterial growth of host pathogen P. syringae pv. maculicola, compared to wild-type Col-0. Moreover, the regulation of stomatal aperture by bacterial pathogens was altered in Gα and Gβ mutants but not in any of the single or double Gγ mutants. Taken together, these data substantiate the critical role of heterotrimeric G-proteins in plant innate immunity and stomatal modulation in response to P. syringae. PMID:24349286

  11. Transient Expression and Cellular Localization of Recombinant Proteins in Cultured Insect Cells.

    PubMed

    Fabrick, Jeffrey A; Hull, J Joe

    2017-04-20

    Heterologous protein expression systems are used for the production of recombinant proteins, the interpretation of cellular trafficking/localization, and the determination of the biochemical function of proteins at the sub-organismal level. Although baculovirus expression systems are increasingly used for protein production in numerous biotechnological, pharmaceutical, and industrial applications, nonlytic systems that do not involve viral infection have clear benefits but are often overlooked and underutilized. Here, we describe a method for generating nonlytic expression vectors and transient recombinant protein expression. This protocol allows for the efficient cellular localization of recombinant proteins and can be used to rapidly discern protein trafficking within the cell. We show the expression of four recombinant proteins in a commercially available insect cell line, including two aquaporin proteins from the insect Bemisia tabaci, as well as subcellular marker proteins specific for the cell plasma membrane and for intracellular lysosomes. All recombinant proteins were produced as chimeras with fluorescent protein markers at their carboxyl termini, which allows for the direct detection of the recombinant proteins. The double transfection of cells with plasmids harboring constructs for the genes of interest and a known subcellular marker allows for live cell imaging and improved validation of cellular protein localization.

  12. Differential profiles of direct and indirect modification of vector feeding behaviour by a plant virus.

    PubMed

    He, Wen-Bo; Li, Jie; Liu, Shu-Sheng

    2015-01-08

    Plant viruses interact with their insect vectors directly and indirectly via host plants, and this tripartite interaction may produce fitness benefits to both the vectors and the viruses. Our previous studies show that the Middle East-Asia Minor 1 (MEAM1) species of the whitefly Bemisia tabaci complex improved its performance on tobacco plants infected by the Tomato yellow leaf curl China virus (TYLCCNV), which it transmits, although virus infection of the whitefly per se reduced its performance. Here, we use electrical penetration graph recording to investigate the direct and indirect effects of TYLCCNV on the feeding behaviour of MEAM1. When feeding on either cotton, a non-host of TYLCCNV, or uninfected tobacco, a host of TYLCCNV, virus-infection of the whiteflies impeded their feeding. Interestingly, when viruliferous whiteflies fed on virus-infected tobacco, their feeding activities were no longer negatively affected; instead, the virus promoted whitefly behaviour related to rapid and effective sap ingestion. Our findings show differential profiles of direct and indirect modification of vector feeding behaviour by a plant virus, and help to unravel the behavioural mechanisms underlying a mutualistic relationship between an insect vector and a plant virus that also has features reminiscent of an insect pathogen.

  13. Natal Host Plants Can Alter Herbivore Competition.

    PubMed

    Pan, Huipeng; Preisser, Evan L; Su, Qi; Jiao, Xiaoguo; Xie, Wen; Wang, Shaoli; Wu, Qingjun; Zhang, Youjun

    2016-01-01

    Interspecific competition between herbivores is widely recognized as an important determinant of community structure. Although researchers have identified a number of factors capable of altering competitive interactions, few studies have addressed the influence of neighboring plant species. If adaptation to/ epigenetic effects of an herbivore's natal host plant alter its performance on other host plants, then interspecific herbivore interactions may play out differently in heterogeneous and homogenous plant communities. We tested wether the natal host plant of a whitefly population affected interactions between the Middle-east Asia Minor 1 (MEAM1) and Mediterranean (MED) cryptic species of the whitefly Bemisia tabaci by rearing the offspring of a cabbage-derived MEAM1 population and a poinsettia-derived MED population together on three different host plants: cotton, poinsettia, and cabbage. We found that MED dominated on poinsettia and that MEAM1 dominated on cabbage, results consistent with previous research. MED also dominated when reared with MEAM1 on cotton, however, a result at odds with multiple otherwise-similar studies that reared both species on the same natal plant. Our work provides evidence that natal plants affect competitive interactions on another plant species, and highlights the potential importance of neighboring plant species on herbivore community composition in agricultral systems.

  14. A massive incorporation of microbial genes into the genome of Tetranychus urticae, a polyphagous arthropod herbivore.

    PubMed

    Wybouw, N; Van Leeuwen, T; Dermauw, W

    2018-06-01

    A number of horizontal gene transfers (HGTs) have been identified in the spider mite Tetranychus urticae, a chelicerate herbivore. However, the genome of this mite species has at present not been thoroughly mined for the presence of HGT genes. Here, we performed a systematic screen for HGT genes in the T. urticae genome using the h-index metric. Our results not only validated previously identified HGT genes but also uncovered 25 novel HGT genes. In addition to HGT genes with a predicted biochemical function in carbohydrate, lipid and folate metabolism, we also identified the horizontal transfer of a ketopantoate hydroxymethyltransferase and a pantoate β-alanine ligase gene. In plants and bacteria, both genes are essential for vitamin B5 biosynthesis and their presence in the mite genome strongly suggests that spider mites, similar to Bemisia tabaci and nematodes, can synthesize their own vitamin B5. We further show that HGT genes were physically embedded within the mite genome and were expressed in different life stages. By screening chelicerate genomes and transcriptomes, we were able to estimate the evolutionary histories of these HGTs during chelicerate evolution. Our study suggests that HGT has made a significant and underestimated impact on the metabolic repertoire of plant-feeding spider mites. © 2018 The Royal Entomological Society.

  15. Natal Host Plants Can Alter Herbivore Competition

    PubMed Central

    Pan, Huipeng; Preisser, Evan L.; Su, Qi; Jiao, Xiaoguo; Xie, Wen; Wang, Shaoli; Wu, Qingjun

    2016-01-01

    Interspecific competition between herbivores is widely recognized as an important determinant of community structure. Although researchers have identified a number of factors capable of altering competitive interactions, few studies have addressed the influence of neighboring plant species. If adaptation to/ epigenetic effects of an herbivore’s natal host plant alter its performance on other host plants, then interspecific herbivore interactions may play out differently in heterogeneous and homogenous plant communities. We tested wether the natal host plant of a whitefly population affected interactions between the Middle-east Asia Minor 1 (MEAM1) and Mediterranean (MED) cryptic species of the whitefly Bemisia tabaci by rearing the offspring of a cabbage-derived MEAM1 population and a poinsettia-derived MED population together on three different host plants: cotton, poinsettia, and cabbage. We found that MED dominated on poinsettia and that MEAM1 dominated on cabbage, results consistent with previous research. MED also dominated when reared with MEAM1 on cotton, however, a result at odds with multiple otherwise-similar studies that reared both species on the same natal plant. Our work provides evidence that natal plants affect competitive interactions on another plant species, and highlights the potential importance of neighboring plant species on herbivore community composition in agricultral systems. PMID:28030636

  16. The Facultative Symbiont Rickettsia Protects an Invasive Whitefly against Entomopathogenic Pseudomonas syringae Strains.

    PubMed

    Hendry, Tory A; Hunter, Martha S; Baltrus, David A

    2014-12-01

    Facultative endosymbionts can benefit insect hosts in a variety of ways, including context-dependent roles, such as providing defense against pathogens. The role of some symbionts in defense may be overlooked, however, when pathogen infection is transient, sporadic, or asymptomatic. The facultative endosymbiont Rickettsia increases the fitness of the sweet potato whitefly (Bemisia tabaci) in some populations through mechanisms that are not yet understood. In this study, we investigated the role of Rickettsia in mediating the interaction between the sweet potato whitefly and Pseudomonas syringae, a common environmental bacterium, some strains of which are pathogenic to aphids. Our results show that P. syringae multiplies within whiteflies, leading to host death, and that whiteflies infected with Rickettsia show a decreased rate of death due to P. syringae. Experiments using plants coated with P. syringae confirmed that whiteflies can acquire the bacteria at a low rate while feeding, leading to increased mortality, particularly when the whiteflies are not infected with Rickettsia. These results suggest that P. syringae may affect whitefly populations in nature and that Rickettsia can ameliorate this effect. This study highlights the possible importance of interactions among opportunistic environmental pathogens and endosymbionts of insects. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  17. The Incredible Journey of Begomoviruses in Their Whitefly Vector

    PubMed Central

    Czosnek, Henryk; Hariton-Shalev, Aliza; Sobol, Iris; Gorovits, Rena; Ghanim, Murad

    2017-01-01

    Begomoviruses are vectored in a circulative persistent manner by the whitefly Bemisia tabaci. The insect ingests viral particles with its stylets. Virions pass along the food canal and reach the esophagus and the midgut. They cross the filter chamber and the midgut into the haemolymph, translocate into the primary salivary glands and are egested with the saliva into the plant phloem. Begomoviruses have to cross several barriers and checkpoints successfully, while interacting with would-be receptors and other whitefly proteins. The bulk of the virus remains associated with the midgut and the filter chamber. In these tissues, viral genomes, mainly from the tomato yellow leaf curl virus (TYLCV) family, may be transcribed and may replicate. However, at the same time, virus amounts peak, and the insect autophagic response is activated, which in turn inhibits replication and induces the destruction of the virus. Some begomoviruses invade tissues outside the circulative pathway, such as ovaries and fat cells. Autophagy limits the amounts of virus associated with these organs. In this review, we discuss the different sites begomoviruses need to cross to complete a successful circular infection, the role of the coat protein in this process and the sites that balance between virus accumulation and virus destruction. PMID:28946649

  18. Differential profiles of direct and indirect modification of vector feeding behaviour by a plant virus

    PubMed Central

    He, Wen-Bo; Li, Jie; Liu, Shu-Sheng

    2015-01-01

    Plant viruses interact with their insect vectors directly and indirectly via host plants, and this tripartite interaction may produce fitness benefits to both the vectors and the viruses. Our previous studies show that the Middle East-Asia Minor 1 (MEAM1) species of the whitefly Bemisia tabaci complex improved its performance on tobacco plants infected by the Tomato yellow leaf curl China virus (TYLCCNV), which it transmits, although virus infection of the whitefly per se reduced its performance. Here, we use electrical penetration graph recording to investigate the direct and indirect effects of TYLCCNV on the feeding behaviour of MEAM1. When feeding on either cotton, a non-host of TYLCCNV, or uninfected tobacco, a host of TYLCCNV, virus-infection of the whiteflies impeded their feeding. Interestingly, when viruliferous whiteflies fed on virus-infected tobacco, their feeding activities were no longer negatively affected; instead, the virus promoted whitefly behaviour related to rapid and effective sap ingestion. Our findings show differential profiles of direct and indirect modification of vector feeding behaviour by a plant virus, and help to unravel the behavioural mechanisms underlying a mutualistic relationship between an insect vector and a plant virus that also has features reminiscent of an insect pathogen. PMID:25567524

  19. Plantmediated horizontal transmission of Wolbachia between whiteflies

    PubMed Central

    Li, Shao-Jian; Ahmed, Muhammad Z; Lv, Ning; Shi, Pei-Qiong; Wang, Xing-Min; Huang, Ji-Lei; Qiu, Bao-Li

    2017-01-01

    Maternal transmission is the main transmission pathway of facultative bacterial endosymbionts, but phylogenetically distant insect hosts harbor closely related endosymbionts, suggesting that horizontal transmission occurs in nature. Here we report the first case of plant-mediated horizontal transmission of Wolbachia between infected and uninfected Bemisia tabaci AsiaII7 whiteflies. After infected whiteflies fed on cotton leaves, Wolbachia was visualized, both in the phloem vessels and in some novel ‘reservoir' spherules along the phloem by fluorescence in situ hybridization using Wolbachia-specific 16S rRNA probes and transmission electron microscopy. Wolbachia persisted in the plant leaves for at least 50 days. When the Wolbachia-free whiteflies fed on the infected plant leaves, the majority of them became infected with the symbiont and vertically transmitted it to their progeny. Multilocus sequence typing and sequencing of the wsp (Wolbachia surface protein) gene confirmed that the sequence type of Wolbachia in the donor whiteflies, cotton phloem and the recipient whiteflies are all identical (sequence type 388). These results were replicated using cowpea and cucumber plants, suggesting that horizontal transmission is also possible through other plant species. Our findings may help explain why Wolbachia bacteria are so abundant in arthropods, and suggest that in some species, Wolbachia may be maintained in populations by horizontal transmission. PMID:27935594

  20. Effects of Interplanting Flowering Plants on the Biological Control of Corn Earworm (Lepidoptera: Noctuidae) and Thrips (Thysanoptera: Thripidae) in Sweet Corn.

    PubMed

    Manandhar, Roshan; Wright, Mark G

    2016-02-01

    Natural enemy exploitation of food resources and alternative hosts in noncrop vegetation has been shown to be an effective means of enhancing natural enemy populations in diversified agro-ecosystem. Field trials were conducted in Hawaii to examine effects of interplanting flowering plants on 1) parasitism of corn earworm, Helicoverpa zea (Boddie) eggs by Trichogramma spp., and 2) abundance of Orius spp. in relation to prey (H. zea eggs and thrips [primarily, Frankliniella occidentalis (Pergande) and Frankliniella williamsi Hood]). Sweet corn (maize), Zea mays L., was interplanted with three flowering plants, buckwheat, Fagopyrum esculentum Moench, cowpea, Vigna unguiculata (L.), and sunn hemp, Crotolaria juncea L., at 2:1 and 4:1 (corn: flowering plant) ratios in 2009 and 2010, respectively. In 2009, the abundance of Orius spp. was significantly greater in the buckwheat-interplanted treatment compared to the monocrop control at similar levels of prey availability, indicating buckwheat flowers might have provided both prey and nectar resources. In 2010, cowpea and sunn hemp flowering plants provided a source of an alternate host insect's eggs for Trichogramma spp. oviposition, resulting in significantly higher parasitism of H. zea eggs in the cowpea- and sunn hemp-interplanted treatments compared to the monocrop control. Despite of differences in pest and natural enemy interactions in two field trials, our findings suggested that provisioning of an alternate host insect's eggs through flowering plants is an effective means for enhancing Trichogramma spp. and provisioning of both nectar and prey resources through flowering plants is important for enhancing predation by Orius spp. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.