Science.gov

Sample records for assessing non-chemical weeding

  1. A non-chemical system for online weed control.

    PubMed

    Rueda-Ayala, Victor; Peteinatos, Gerassimos; Gerhards, Roland; Andújar, Dionisio

    2015-01-01

    Non-chemical weed control methods need to be directed towards a site-specific weeding approach, in order to be able to compete the conventional herbicide equivalents. A system for online weed control was developed. It automatically adjusts the tine angle of a harrow and creates different levels of intensity: from gentle to aggressive. Two experimental plots in a maize field were harrowed with two consecutive passes. The plots presented from low to high weed infestation levels. Discriminant capabilities of an ultrasonic sensor were used to determine the crop and weed variability of the field. A controlling unit used ultrasonic readings to adjust the tine angle, producing an appropriate harrowing intensity. Thus, areas with high crop and weed densities were more aggressively harrowed, while areas with lower densities were cultivated with a gentler treatment; areas with very low densities or without weeds were not treated. Although the weed development was relatively advanced and the soil surface was hard, the weed control achieved by the system reached an average of 51% (20%-91%), without causing significant crop damage as a result of harrowing. This system is proposed as a relatively low cost, online, and real-time automatic harrow that improves the weed control efficacy, reduces energy consumption, and avoids the usage of herbicide. PMID:25831085

  2. A Non-Chemical System for Online Weed Control

    PubMed Central

    Rueda-Ayala, Victor; Peteinatos, Gerassimos; Gerhards, Roland; Andújar, Dionisio

    2015-01-01

    Non-chemical weed control methods need to be directed towards a site-specific weeding approach, in order to be able to compete the conventional herbicide equivalents. A system for online weed control was developed. It automatically adjusts the tine angle of a harrow and creates different levels of intensity: from gentle to aggressive. Two experimental plots in a maize field were harrowed with two consecutive passes. The plots presented from low to high weed infestation levels. Discriminant capabilities of an ultrasonic sensor were used to determine the crop and weed variability of the field. A controlling unit used ultrasonic readings to adjust the tine angle, producing an appropriate harrowing intensity. Thus, areas with high crop and weed densities were more aggressively harrowed, while areas with lower densities were cultivated with a gentler treatment; areas with very low densities or without weeds were not treated. Although the weed development was relatively advanced and the soil surface was hard, the weed control achieved by the system reached an average of 51% (20%–91%), without causing significant crop damage as a result of harrowing. This system is proposed as a relatively low cost, online, and real-time automatic harrow that improves the weed control efficacy, reduces energy consumption, and avoids the usage of herbicide. PMID:25831085

  3. Anaerobic soil disinfestation for non-chemical weed control in Florida raised-bed vegetable production.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There is an increased interest in non-chemical weed control alternatives to soil fumigation with methyl bromide. One such approach is the use of anaerobic soil disinfestation (ASD), which combines the approaches of biological soil disinfestation and soil reduction sterilization. ASD combines heati...

  4. Applying a weed risk assessment approach to GM crops.

    PubMed

    Keese, Paul K; Robold, Andrea V; Myers, Ruth C; Weisman, Sarah; Smith, Joe

    2014-12-01

    Current approaches to environmental risk assessment of genetically modified (GM) plants are modelled on chemical risk assessment methods, which have a strong focus on toxicity. There are additional types of harms posed by plants that have been extensively studied by weed scientists and incorporated into weed risk assessment methods. Weed risk assessment uses robust, validated methods that are widely applied to regulatory decision-making about potentially problematic plants. They are designed to encompass a broad variety of plant forms and traits in different environments, and can provide reliable conclusions even with limited data. The knowledge and experience that underpin weed risk assessment can be harnessed for environmental risk assessment of GM plants. A case study illustrates the application of the Australian post-border weed risk assessment approach to a representative GM plant. This approach is a valuable tool to identify potential risks from GM plants. PMID:24046097

  5. Laboratory tests to assess optimal agricultural residue traits for an abrasive weed control system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    One of the biggest challenges to organic agricultural production and herbicide resistant crops in industrialized countries today is the non-chemical control of weed plants. Studies of new tools and methods for weed control have been motivated by an increased consumer demand for organic produce and c...

  6. Non-Chemical Stressors and Cumulative Risk Assessment: An Overview of Current Initiatives and Potential Air Pollutant Interactions

    PubMed Central

    Lewis, Ari S.; Sax, Sonja N.; Wason, Susan C.; Campleman, Sharan L.

    2011-01-01

    Regulatory agencies are under increased pressure to consider broader public health concerns that extend to multiple pollutant exposures, multiple exposure pathways, and vulnerable populations. Specifically, cumulative risk assessment initiatives have stressed the importance of considering both chemical and non-chemical stressors, such as socioeconomic status (SES) and related psychosocial stress, in evaluating health risks. The integration of non-chemical stressors into a cumulative risk assessment framework has been largely driven by evidence of health disparities across different segments of society that may also bear a disproportionate risk from chemical exposures. This review will discuss current efforts to advance the field of cumulative risk assessment, highlighting some of the major challenges, discussed within the construct of the traditional risk assessment paradigm. Additionally, we present a summary of studies of potential interactions between social stressors and air pollutants on health as an example of current research that supports the incorporation of non-chemical stressors into risk assessment. The results from these studies, while suggestive of possible interactions, are mixed and hindered by inconsistent application of social stress indicators. Overall, while there have been significant advances, further developments across all of the risk assessment stages (i.e., hazard identification, exposure assessment, dose-response, and risk characterization) are necessary to provide a scientific basis for regulatory actions and effective community interventions, particularly when considering non-chemical stressors. A better understanding of the biological underpinnings of social stress on disease and implications for chemical-based dose-response relationships is needed. Furthermore, when considering non-chemical stressors, an appropriate metric, or series of metrics, for risk characterization is also needed. Cumulative risk assessment research will benefit

  7. Adapting Chemical Mixture Risk Assessment Methods to Assess Chemical and Non-Chemical Stressor Combinations

    EPA Science Inventory

    Presentation based on the following abstract: Chemical mixtures risk assessment methods are routinely used. To address combined chemical and nonchemical stressors, component-based approaches may be applicable, depending on the toxic action among diverse stressors. Such methods a...

  8. APPROACHES FOR INCORPORATING NON-CHEMICAL STRESSORS INTO CUMULATIVE RISK ASSESSMENTS

    EPA Science Inventory

    Over the past twenty years, the risk assessment paradigm has gradually shifted from an individual chemical approach to a community-based model. Inherent in community-based risk assessment is consideration of the totality of stressors affecting a defined population including both ...

  9. Evaluating Exposures to Chemical and Non-Chemical Stressors in a Cumulative Risk Assessment

    EPA Science Inventory

    Characteristically toxicological and epidemiological studies involving chemical mixtures (e.g., multi-pollutant exposures) have been increasing. Human health assessment of chemical and nonchemical mixture risk remains rare. Recently, there has been an increased emphasis on integr...

  10. Weed Management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Adaptive management can complement integrated programs to manage weeds in forage production systems. This approach requires establishing management goals, developing and implementing management programs based on the goals, monitoring and assessing impacts of management efforts, and modifying goals a...

  11. Environmental risk assessment of compost prepared from salvinia, egeria densa, and alligator weed.

    PubMed

    Dorahy, C G; Pirie, A D; McMaster, I; Muirhead, L; Pengelly, P; Chan, K Y; Jackson, M; Barchia, I M

    2009-01-01

    Approximately 70,000 m(3) of salvinia (Salvinia molesta) was removed from the Hawkesbury-Nepean River, New South Wales (NSW), Australia, during 2004. This study assessed the risks associated with applying compost prepared from aquatic weeds (AWC) to land, namely, survival and spread of aquatic and terrestrial weeds, eutrophication of waterways, accumulation of heavy metals and phytotoxicity. The results demonstrate composting is an effective method of reducing the viability of aquatic and terrestrial weeds. However, mortality of alligator weed (Alternanthera philoxeroides), which was used as an indicator plant, was significantly (P < 0.001) correlated with the temperature within the windrows and the length of time the material was subjected to composting. Conditions within the central core of the windrow were sufficient to kill the alligator weed, although not all of the aquatic weed material was exposed to the windrows' central core. This resulted in alligator weed continuing to grow at the base of the windrow. To reduce the risk of weeds surviving and spreading in aquatic and terrestrial environments it is suggested compost windrows should be located on an appropriate hard pad to enable complete mixing of the material and ensure all material is exposed to temperatures >55 degrees C for greater than three consecutive days. The likelihood of other risks associated with the AWC was low. If composting is selected as the preferred method for managing organic material harvested from waterways, then ongoing monitoring and evaluation is required to validate the composting process and ensure consumer confidence in the final product. PMID:19465724

  12. An analysis of assessment outcomes from eight years' operation of the Australian border weed risk assessment system.

    PubMed

    Weber, Jason; Dane Panetta, F; Virtue, John; Pheloung, Paul

    2009-02-01

    The majority of Australian weeds are exotic plant species that were intentionally introduced for a variety of horticultural and agricultural purposes. A border weed risk assessment system (WRA) was implemented in 1997 in order to reduce the high economic costs and massive environmental damage associated with introducing serious weeds. We review the behaviour of this system with regard to eight years of data collected from the assessment of species proposed for importation or held within genetic resource centres in Australia. From a taxonomic perspective, species from the Chenopodiaceae and Poaceae were most likely to be rejected and those from the Arecaceae and Flacourtiaceae were most likely to be accepted. Dendrogram analysis and classification and regression tree (TREE) models were also used to analyse the data. The latter revealed that a small subset of the 35 variables assessed was highly associated with the outcome of the original assessment. The TREE model examining all of the data contained just five variables: unintentional human dispersal, congeneric weed, weed elsewhere, tolerates or benefits from mutilation, cultivation or fire, and reproduction by vegetative propagation. It gave the same outcome as the full WRA model for 71% of species. Weed elsewhere was not the first splitting variable in this model, indicating that the WRA has a capacity for capturing species that have no history of weediness. A reduced TREE model (in which human-mediated variables had been removed) contained four variables: broad climate suitability, reproduction in less or than equal to 1year, self-fertilisation, and tolerates and benefits from mutilation, cultivation or fire. It yielded the same outcome as the full WRA model for 65% of species. Data inconsistencies and the relative importance of questions are discussed, with some recommendations made for improving the use of the system. PMID:18339471

  13. Global climate change and carbon dioxide: Assessing weed biology and management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Both increasing carbon dioxide and climate change are likely to alter weed biology in a myriad of ways. In this chapter, I provide an overview of the methodology by which rising carbon dioxide and climate uncertainty are likely to effect weed establishment, growth and fecundity, the implications fo...

  14. 76 FR 39811 - International Center for Technology Assessment and the Center for Food Safety; Noxious Weed...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-07

    ... engineered for tolerance to the herbicide glyphosate should not be listed as a Federal noxious weed and... tolerance to the herbicide glyphosate, as Federal noxious weeds. On May 13, 2003, APHIS responded to the... genetically engineered for tolerance to the herbicide glyphosate as well as non-herbicide-tolerant...

  15. WEED RESEARCH

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weeds in peppermint and spearmint reduce mint oil yield and quality. Presence of weeds in mint hay at harvest can result in off flavors, odors, and colors in the oil. Several weed species have developed resistance to, or are poorly controlled by herbicides labeled for mint production. Pigweed is oft...

  16. Agronomic Weeds.

    ERIC Educational Resources Information Center

    Hartwig, Nathan L.

    This agriculture extension service publication from Pennsylvania State University examines agronomic weed problems and control. Contents include a listing of the characteristics of weeds, a section on herbicides, and a section on the important weeds of agronomic crops in Pennsylvania. The herbicide section discusses systemic herbicides, contact…

  17. Weed control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Uncontrolled weeds in pepper can result in the total loss of the crop, or make harvest not economically feasible. Weed control is a major challenge in conventional and organic production systems. Agricultural weed control costs the U.S. economy more than the cost of insect and disease control comb...

  18. Weed Risk Assessment for Aquatic Plants: Modification of a New Zealand System for the United States

    PubMed Central

    Gordon, Doria R.; Gantz, Crysta A.; Jerde, Christopher L.; Chadderton, W. Lindsay; Keller, Reuben P.; Champion, Paul D.

    2012-01-01

    We tested the accuracy of an invasive aquatic plant risk assessment system in the United States that we modified from a system originally developed by New Zealand’s Biosecurity Program. The US system is comprised of 38 questions that address biological, historical, and environmental tolerance traits. Values associated with each response are summed to produce a total score for each species that indicates its risk of invasion. To calibrate and test this risk assessment, we identified 39 aquatic plant species that are major invaders in the continental US, 31 species that have naturalized but have no documented impacts (minor invaders), and 60 that have been introduced but have not established. These species represent 55 families and span all aquatic plant growth forms. We found sufficient information to assess all but three of these species. When the results are compared to the known invasiveness of the species, major invaders are distinguished from minor and non-invaders with 91% accuracy. Using this approach, the US aquatic weed risk assessment correctly identifies major invaders 85%, and non-invaders 98%, of the time. Model validation using an additional 10 non-invaders and 10 invaders resulted in 100% accuracy for the former, and 80% accuracy for the latter group. Accuracy was further improved to an average of 91% for all groups when the 17% of species with scores of 31–39 required further evaluation prior to risk classification. The high accuracy with which we can distinguish non-invaders from harmful invaders suggests that this tool provides a feasible, pro-active system for pre-import screening of aquatic plants in the US, and may have additional utility for prioritizing management efforts of established species. PMID:22808088

  19. The future for weed control and technology.

    PubMed

    Shaner, Dale L; Beckie, Hugh J

    2014-09-01

    This review is both a retrospective (what have we missed?) and prospective (where are we going?) examination of weed control and technology, particularly as it applies to herbicide-resistant weed management (RWM). Major obstacles to RWM are discussed, including lack of diversity in weed management, unwillingness of many weed researchers to conduct real integrated weed management research or growers to accept recommendations, influence or role of agrichemical marketing and governmental policy and lack of multidisciplinary research. We then look ahead to new technologies that are needed for future weed control in general and RWM in particular, in areas such as non-chemical and chemical weed management, novel herbicides, site-specific weed management, drones for monitoring large areas, wider application of 'omics' and simulation model development. Finally, we discuss implementation strategies for integrated weed management to achieve RWM, development of RWM for developing countries, a new classification of herbicides based on mode of metabolism to facilitate greater stewardship and greater global exchange of information to focus efforts on areas that maximize progress in weed control and RWM. There is little doubt that new or emerging technologies will provide novel tools for RMW in the future, but will they arrive in time? PMID:24339388

  20. Flowers & Weeds.

    ERIC Educational Resources Information Center

    Flannery, Maura C.

    1996-01-01

    Describes the topics and teaching strategies employed in an Issues in Biology course. Discusses flowers, plant breeding, potatoes and tomatoes, the chocolate tree, weeds, Arabidopis, gene transfers, and plant genes/human genes. Contains 22 references. (JRH)

  1. Weeding Your Collection.

    ERIC Educational Resources Information Center

    Kerby, Ramona

    2002-01-01

    Offers guidelines for weeding as part of school library collection development. Highlights include developing a weeding policy; and the CREW (Continuous Review Evaluation and Weeding) method, including reasons for weeding, scheduling, and guidelines for fiction and for nonfiction. (LRW)

  2. Assessing Environmental Risks for Established Invasive Weeds: Dalmatian (Linaria dalmatica) and Yellow (L. vulgaris) Toadflax in North America

    PubMed Central

    Sing, Sharlene E.; Peterson, Robert K. D.

    2011-01-01

    Environmental risk assessments characterizing potential environmental impacts of exotic weeds are more abundant and comprehensive for potential or new invaders than for widespread and well-established species such as Dalmatian (Linaria dalmatica [L.] Mill.) and yellow (L. vulgaris Mill.) toadflax. Specific effects evaluated in our assessment of environmental risks posed by yellow and Dalmatian toadflax included competitive displacement of other plant species, reservoirs of plant disease, animal and insect use, animal toxicity, human toxicity and allergenicity, erosion, and wildfire. Effect and exposure uncertainties for potential impacts of toadflax on human and ecological receptors were rated. Using publicly available information we were able to characterize ecological and human health impacts associated with toadflax, and to identify specific data gaps contributing to a high uncertainty of risk. Evidence supporting perceived negative environmental impacts of invasive toadflax was scarce. PMID:21845161

  3. Green Weeding

    ERIC Educational Resources Information Center

    Penniman, Sarah; McColl, Lisa

    2008-01-01

    Gone are the days of tiptoeing to the dumpsters with boxes of weeded books in tow. Lots of libraries are now taking advantage of the many low-cost services and solutions that promise to help extend the lives of collection discards. Some of these options can be very profitable. Some create goodwill within the local community. Some may seem more…

  4. Winter Weeds.

    ERIC Educational Resources Information Center

    Lindberg, Lois

    1981-01-01

    Try to learn all you can about a plant in the winter. As the season changes, you can see what the dried seed pod is like in bloom. You are a convert if you notice a spectacular show of summer wildflowers and wonder what sort of winter weed will result. (Author/CM)

  5. Assessing insecticide hazard to bumble bees foraging on flowering weeds in treated lawns.

    PubMed

    Larson, Jonathan L; Redmond, Carl T; Potter, Daniel A

    2013-01-01

    Maintaining bee-friendly habitats in cities and suburbs can help conserve the vital pollination services of declining bee populations. Despite label precautions not to apply them to blooming plants, neonicotinoids and other residual systemic insecticides may be applied for preventive control of lawn insect pests when spring-flowering weeds are present. Dietary exposure to neonicotinoids adversely affects bees, but the extent of hazard from field usage is controversial. We exposed colonies of the bumble bee Bombus impatiens to turf with blooming white clover that had been treated with clothianidin, a neonicotinoid, or with chlorantraniliprole, the first anthranilic diamide labeled for use on lawns. The sprays were applied at label rate and lightly irrigated. After residues had dried, colonies were confined to forage for six days, and then moved to a non-treated rural site to openly forage and develop. Colonies exposed to clothianidin-treated weedy turf had delayed weight gain and produced no new queens whereas those exposed to chlorantraniliprole-treated plots developed normally compared with controls. Neither bumble bees nor honey bees avoided foraging on treated white clover in open plots. Nectar from clover blooms directly contaminated by spray residues contained 171±44 ppb clothianidin. Notably, neither insecticide adversely impacted bee colonies confined on the treated turf after it had been mown to remove clover blooms present at the time of treatment, and new blooms had formed. Our results validate EPA label precautionary statements not to apply neonicotinoids to blooming nectar-producing plants if bees may visit the treatment area. Whatever systemic hazard through lawn weeds they may pose appears transitory, however, and direct hazard can be mitigated by adhering to label precautions, or if blooms inadvertently are contaminated, by mowing to remove them. Chlorantraniliprole usage on lawns appears non-hazardous to bumble bees. PMID:23776667

  6. Assessing Insecticide Hazard to Bumble Bees Foraging on Flowering Weeds in Treated Lawns

    PubMed Central

    Larson, Jonathan L.; Redmond, Carl T.; Potter, Daniel A.

    2013-01-01

    Maintaining bee-friendly habitats in cities and suburbs can help conserve the vital pollination services of declining bee populations. Despite label precautions not to apply them to blooming plants, neonicotinoids and other residual systemic insecticides may be applied for preventive control of lawn insect pests when spring-flowering weeds are present. Dietary exposure to neonicotinoids adversely affects bees, but the extent of hazard from field usage is controversial. We exposed colonies of the bumble bee Bombus impatiens to turf with blooming white clover that had been treated with clothianidin, a neonicotinoid, or with chlorantraniliprole, the first anthranilic diamide labeled for use on lawns. The sprays were applied at label rate and lightly irrigated. After residues had dried, colonies were confined to forage for six days, and then moved to a non-treated rural site to openly forage and develop. Colonies exposed to clothianidin-treated weedy turf had delayed weight gain and produced no new queens whereas those exposed to chlorantraniliprole-treated plots developed normally compared with controls. Neither bumble bees nor honey bees avoided foraging on treated white clover in open plots. Nectar from clover blooms directly contaminated by spray residues contained 171±44 ppb clothianidin. Notably, neither insecticide adversely impacted bee colonies confined on the treated turf after it had been mown to remove clover blooms present at the time of treatment, and new blooms had formed. Our results validate EPA label precautionary statements not to apply neonicotinoids to blooming nectar-producing plants if bees may visit the treatment area. Whatever systemic hazard through lawn weeds they may pose appears transitory, however, and direct hazard can be mitigated by adhering to label precautions, or if blooms inadvertently are contaminated, by mowing to remove them. Chlorantraniliprole usage on lawns appears non-hazardous to bumble bees. PMID:23776667

  7. Weed control without herbicides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Managing weeds without herbicides is challenging and requires an integration of tactics and a change in how weeds problems are approached. Weeds should be managed in a holistic, intentional and proactive manner. Growers that successfully manage weeds in organic systems examine why certain weed speci...

  8. Subplots facilitate assessment of corn yield losses from weed competition in a long-term systems experiment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weeds can potentially limit crop yield, particularly in organic systems where herbicide technologies are unavailable. Weedy and weed-free subplots were established within full plots of a long-term cropping systems experiment, the Farming Systems Project, at Beltsville, Maryland, USA, to determine t...

  9. Ambient insect pressure and recipient genotypes determine fecundity of transgenic crop-weed rice hybrid progeny: Implications for environmental biosafety assessment.

    PubMed

    Xia, Hui; Zhang, Hongbin; Wang, Wei; Yang, Xiao; Wang, Feng; Su, Jun; Xia, Hanbing; Xu, Kai; Cai, Xingxing; Lu, Bao-Rong

    2016-08-01

    Transgene introgression into crop weedy/wild relatives can provide natural selective advantages, probably causing undesirable environmental impact. The advantages are likely associated with factors such as transgenes, selective pressure, and genetic background of transgene recipients. To explore the role of the environment and background of transgene recipients in affecting the advantages, we estimated the fitness of crop-weed hybrid lineages derived from crosses between marker-free insect-resistant transgenic (Bt/CpTI) rice with five weedy rice populations under varied insect pressure. Multiway anova indicated the significant effect of both transgenes and weedy rice genotypes on the performance of crop-weed hybrid lineages in the high-insect environment. Increased fecundity was detected in most transgene-present F1 and F2 hybrid lineages under high-insect pressure, but varied among crop-weed hybrid lineages with different weedy rice parents. Increased fecundity of transgenic crop-weed hybrid lineages was associated with the environmental insect pressure and genotypes of their weedy rice parents. The findings suggest that the fitness effects of an insect-resistant transgene introgressed into weedy populations are not uniform across different environments and genotypes of the recipient plants that have acquired the transgene. Therefore, these factors should be considered when assessing the environmental impact of transgene flow to weedy or wild rice relatives. PMID:27468303

  10. Non-parasitic weeds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weeds lower potato yield and quality by competing for light, nutrients, water, and space. Weeds can also interfere with harvest operations. Weeds can be categorized into annual, biennial, and perennial based on their life cycle. Perennial weeds live for three years or more and reproduce by various t...

  11. Can Global Weed Assemblages Be Used to Predict Future Weeds?

    PubMed Central

    Morin, Louise; Paini, Dean R.; Randall, Roderick P.

    2013-01-01

    Predicting which plant taxa are more likely to become weeds in a region presents significant challenges to both researchers and government agencies. Often it is done in a qualitative or semi-quantitative way. In this study, we explored the potential of using the quantitative self-organising map (SOM) approach to analyse global weed assemblages and estimate likelihoods of plant taxa becoming weeds before and after they have been moved to a new region. The SOM approach examines plant taxa associations by analysing where a taxon is recorded as a weed and what other taxa are recorded as weeds in those regions. The dataset analysed was extracted from a pre-existing, extensive worldwide database of plant taxa recorded as weeds or other related status and, following reformatting, included 187 regions and 6690 plant taxa. To assess the value of the SOM approach we selected Australia as a case study. We found that the key and most important limitation in using such analytical approach lies with the dataset used. The classification of a taxon as a weed in the literature is not often based on actual data that document the economic, environmental and/or social impact of the taxon, but mostly based on human perceptions that the taxon is troublesome or simply not wanted in a particular situation. The adoption of consistent and objective criteria that incorporate a standardized approach for impact assessment of plant taxa will be necessary to develop a new global database suitable to make predictions regarding weediness using methods like SOM. It may however, be more realistic to opt for a classification system that focuses on the invasive characteristics of plant taxa without any inference to impacts, which to be defined would require some level of research to avoid bias from human perceptions and value systems. PMID:23393591

  12. An Ultrasonic System for Weed Detection in Cereal Crops

    PubMed Central

    Andújar, Dionisio; Weis, Martin; Gerhards, Roland

    2012-01-01

    Site-specific weed management requires sensing of the actual weed infestation levels in agricultural fields to adapt the management accordingly. However, sophisticated sensor systems are not yet in wider practical use, since they are not easily available for the farmers and their handling as well as the management practice requires additional efforts. A new sensor-based weed detection method is presented in this paper and its applicability to cereal crops is evaluated. An ultrasonic distance sensor for the determination of plant heights was used for weed detection. It was hypothesised that the weed infested zones have a higher amount of biomass than non-infested areas and that this can be determined by plant height measurements. Ultrasonic distance measurements were taken in a winter wheat field infested by grass weeds and broad-leaved weeds. A total of 80 and 40 circular-shaped samples of different weed densities and compositions were assessed at two different dates. The sensor was pointed directly to the ground for height determination. In the following, weeds were counted and then removed from the sample locations. Grass weeds and broad-leaved weeds were separately removed. Differences between weed infested and weed-free measurements were determined. Dry-matter of weeds and crop was assessed and evaluated together with the sensor measurements. RGB images were taken prior and after weed removal to determine the coverage percentages of weeds and crop per sampling point. Image processing steps included EGI (excess green index) computation and thresholding to separate plants and background. The relationship between ultrasonic readings and the corresponding coverage of the crop and weeds were assessed using multiple regression analysis. Results revealed a height difference between infested and non-infested sample locations. Density and biomass of weeds present in the sample influenced the ultrasonic readings. The possibilities of weed group discrimination were

  13. Horny Goat Weed

    MedlinePlus

    ... avoid using. Bleeding disorders: Horny goat weed slows blood clotting and might increase the risk of bleeding. However, ... risk of fainting. Surgery: Horny goat weed slows blood clotting and might increase the risk of bleeding during ...

  14. Eradication of Major Weeds

    ERIC Educational Resources Information Center

    Indian Journal of Adult Education, 1975

    1975-01-01

    Strategies for weed control in cropped and non-cropped areas are presented together with an operational plan for implementing a program for weed control at the national level. The program includes training personnel and community education procedures. (EC)

  15. Crop/weed discrimination in simulated images

    NASA Astrophysics Data System (ADS)

    Jones, G.; Gée, C.; Truchetet, F.

    2007-02-01

    In the context of site-specific weed management by vision systems, an efficient image processing for a crop/weed discrimination is required in order to quantify the Weed Infestation Rate (WIR) in an image. This paper presents a modeling of crop field in presence of different Weed Infestation Rates and a set of simulated agronomic images is used to test and validate the effectiveness of a crop/weed discrimination algorithm. For instance, an algorithm has been implemented to firstly detect the crop rows in the field by the use of a Hough Transform and secondly to detect plant areas by a region based-segmentation on binary images. This image processing has been tested on virtual cereal fields of a large field of view with perspective effects. The vegetation in the virtual field is modeled by a sowing pattern for crop plants and the weed spatial distribution is modeled by either a Poisson process or a Neyman-Scott cluster process. For each simulated image, a comparison between the initial and the detected weed infestation rate allows us to assess the accuracy of the algorithm. This comparison demonstrates an accuracy of better than 80% is possible, despite that intrarow weeds can not be detected from this spatial method.

  16. Introduction to Weeds and Herbicides.

    ERIC Educational Resources Information Center

    Hartwig, Nathan L.

    This agriculture extension service publication from Pennsylvania State University is an introduction to weed control and herbicide use. An initial discussion of the characteristics of weeds includes scientific naming, weed competition with crops, weed dispersal and dormancy, and conditions affecting weed seed germination. The main body of the…

  17. Genotoxicity assessment of two common curing weeds: Hyptis suaveolens (L.) Poir. and Leucas indica (L.) R. Br.

    PubMed

    Sumitha, K V; Thoppil, J E

    2016-08-01

    Hyptis suaveolens and Leucas indica, two common weeds were selected for the present study, to reveal their probable cytotoxic potential. The meristematic root tips of Allium cepa were used for testing the cytotoxic property of the aqueous leaf extracts containing both polar and non-polar compounds, and that containing polar compounds alone, at different concentrations (0.125, 0.25, 0.5, 1 and 2 %) and at different time durations, using distilled water as negative control. Mitotic squash preparations were made using a standard protocol. The mitotic index of the treated root tip cells was found to be decreasing and the abnormality percentage was found to be increasing with increase in extract concentration when compared with the control. Maximum cytotoxicity was observed in the extract containing both polar and non-polar compounds. Both the tested plants were found to be cytotoxic. The abnormalities noticed were of both clastogenic (nuclear lesions, nuclear fragmentation, etc.) and non-clastogenic (aberrant cell wall formation at cytokinesis, ball metaphase, etc.) types. Both plant extracts were found to significantly (P < 0.05) inhibit root growth of Allium cepa with an EC50 value of 1.92 % (R(2) = 0.594) for Hyptis and 1.58 % (R(2) = 0.757) for Leucas. The results were also analysed statistically by using analysis of variance followed by appropriate post hoc tests. These two weeds are aromatic plants comprising of essential oils that are volatile, natural complex compounds characterized by a strong odour and formed as secondary metabolites. In nature, essential oils play an important role in the protection of the plants as insecticides by reducing their appetite for such plants. When specifically targeted the concept of effectively exploiting these weeds for the formulation of herbal insecticides/pesticides may be possible in the near future. PMID:26286182

  18. Ecological Intensification Through Pesticide Reduction: Weed Control, Weed Biodiversity and Sustainability in Arable Farming

    NASA Astrophysics Data System (ADS)

    Petit, Sandrine; Munier-Jolain, Nicolas; Bretagnolle, Vincent; Bockstaller, Christian; Gaba, Sabrina; Cordeau, Stéphane; Lechenet, Martin; Mézière, Delphine; Colbach, Nathalie

    2015-11-01

    Amongst the biodiversity components of agriculture, weeds are an interesting model for exploring management options relying on the principle of ecological intensification in arable farming. Weeds can cause severe crop yield losses, contribute to farmland functional biodiversity and are strongly associated with the generic issue of pesticide use. In this paper, we address the impacts of herbicide reduction following a causal framework starting with herbicide reduction and triggering changes in (i) the management options required to control weeds, (ii) the weed communities and functions they provide and (iii) the overall performance and sustainability of the implemented land management options. The three components of this framework were analysed in a multidisciplinary project that was conducted on 55 experimental and farmer's fields that included conventional, integrated and organic cropping systems. Our results indicate that the reduction of herbicide use is not antagonistic with crop production, provided that alternative practices are put into place. Herbicide reduction and associated land management modified the composition of in-field weed communities and thus the functions of weeds related to biodiversity and production. Through a long-term simulation of weed communities based on alternative (?) cropping systems, some specific management pathways were identified that delivered high biodiversity gains and limited the negative impacts of weeds on crop production. Finally, the multi-criteria assessment of the environmental, economic and societal sustainability of the 55 systems suggests that integrated weed management systems fared better than their conventional and organic counterparts. These outcomes suggest that sustainable management could possibly be achieved through changes in weed management, along a pathway starting with herbicide reduction.

  19. Ecological Intensification Through Pesticide Reduction: Weed Control, Weed Biodiversity and Sustainability in Arable Farming.

    PubMed

    Petit, Sandrine; Munier-Jolain, Nicolas; Bretagnolle, Vincent; Bockstaller, Christian; Gaba, Sabrina; Cordeau, Stéphane; Lechenet, Martin; Mézière, Delphine; Colbach, Nathalie

    2015-11-01

    Amongst the biodiversity components of agriculture, weeds are an interesting model for exploring management options relying on the principle of ecological intensification in arable farming. Weeds can cause severe crop yield losses, contribute to farmland functional biodiversity and are strongly associated with the generic issue of pesticide use. In this paper, we address the impacts of herbicide reduction following a causal framework starting with herbicide reduction and triggering changes in (i) the management options required to control weeds, (ii) the weed communities and functions they provide and (iii) the overall performance and sustainability of the implemented land management options. The three components of this framework were analysed in a multidisciplinary project that was conducted on 55 experimental and farmer's fields that included conventional, integrated and organic cropping systems. Our results indicate that the reduction of herbicide use is not antagonistic with crop production, provided that alternative practices are put into place. Herbicide reduction and associated land management modified the composition of in-field weed communities and thus the functions of weeds related to biodiversity and production. Through a long-term simulation of weed communities based on alternative (?) cropping systems, some specific management pathways were identified that delivered high biodiversity gains and limited the negative impacts of weeds on crop production. Finally, the multi-criteria assessment of the environmental, economic and societal sustainability of the 55 systems suggests that integrated weed management systems fared better than their conventional and organic counterparts. These outcomes suggest that sustainable management could possibly be achieved through changes in weed management, along a pathway starting with herbicide reduction. PMID:26071767

  20. Weed Research in Mint

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Production of high quality and high yielding peppermint and spearmint oil requires effective management of weeds. Since soil disturbance is kept to a minimum to reduce the spread of Verticillium wilt in mint production, weed control is accomplished primarily with herbicides. Flucarbazone, and propox...

  1. Mustard meal weed control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed control in organic production systems can be a labor intensive and expensive process. Mustard meal (MM) is phytotoxic and a potential pre-emergent and preplant-incorporated organic herbicide for controlling germinating and emerging weed seedlings. Unfortunately, MM may also adversely impact s...

  2. Herbicide Resistant Weed Management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Metribuzin and rimsulfuron are the only two herbicides registered for postemergence broadleaf weed control in potatoes, and represent the two classes of herbicides, triazines and ALS inhibitors, with the most reported cases of resistant weeds world wide. Other postemergence grass herbicides belongin...

  3. Weed Research in Mint

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weeds present in peppermint and spearmint reduce mint oil yield and quality. Mustard seed meal applied at 1 and 2 ton/acre to newly planted peppermint reduced annual weed emergence for several weeks without injuring peppermint. Field pennycress seed meal applied at similar rates did not suppress wee...

  4. Bioherbicides for Weed Control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Following the first commercially successfully biological control of weeds with fungal pathogens a model for a good bioherbicide was developed. It was assumed that a good agent was one that could be grown cheaply and quickly; was aggressive and patentable; could be easily applied; had single-weed sp...

  5. Epigenome: A Biomarker or Screening Tool to Evaluate Health Impact of Cumulative Exposure to Chemical and Non-Chemical Stressors

    PubMed Central

    Olden, Kenneth; Lin, Yu-Sheng; Bussard, David

    2016-01-01

    Current risk assessment practices and toxicity information are hard to utilize for assessing the health impact of combined or cumulative exposure to multiple chemical and non-chemical stressors encountered in the “real world” environment. Non-chemical stressors such as heat, radiation, noise, humidity, bacterial and viral agents, and social factors, like stress related to violence and socioeconomic position generally cannot be currently incorporated into the risk assessment paradigm. The Science and Decisions report released by the National Research Council (NRC) in 2009 emphasized the need to characterize the effects of multiple stressors, both chemical and non-chemical exposures. One impediment to developing information relating such non-chemical stressors to health effects and incorporating them into cumulative assessment has been the lack of analytical tools to easily and quantitatively monitor the cumulative exposure to combined effects of stressors over the life course. PMID:27398233

  6. Epigenome: A Biomarker or Screening Tool to Evaluate Health Impact of Cumulative Exposure to Chemical and Non-Chemical Stressors.

    PubMed

    Olden, Kenneth; Lin, Yu-Sheng; Bussard, David

    2016-06-01

    Current risk assessment practices and toxicity information are hard to utilize for assessing the health impact of combined or cumulative exposure to multiple chemical and non-chemical stressors encountered in the "real world" environment. Non-chemical stressors such as heat, radiation, noise, humidity, bacterial and viral agents, and social factors, like stress related to violence and socioeconomic position generally cannot be currently incorporated into the risk assessment paradigm. The Science and Decisions report released by the National Research Council (NRC) in 2009 emphasized the need to characterize the effects of multiple stressors, both chemical and non-chemical exposures. One impediment to developing information relating such non-chemical stressors to health effects and incorporating them into cumulative assessment has been the lack of analytical tools to easily and quantitatively monitor the cumulative exposure to combined effects of stressors over the life course. PMID:27398233

  7. Epigenome: A Biomarker or Screening Tool to Evaluate Health Impact of Cumulative Exposure to Chemical and Non-Chemical Stressors.

    PubMed

    Olden, Kenneth; Lin, Yu-Sheng; Bussard, David

    2016-06-01

    Current risk assessment practices and toxicity information are hard to utilize for assessing the health impact of combined or cumulative exposure to multiple chemical and non-chemical stressors encountered in the "real world" environment. Non-chemical stressors such as heat, radiation, noise, humidity, bacterial and viral agents, and social factors, like stress related to violence and socioeconomic position generally cannot be currently incorporated into the risk assessment paradigm. The Science and Decisions report released by the National Research Council (NRC) in 2009 emphasized the need to characterize the effects of multiple stressors, both chemical and non-chemical exposures. One impediment to developing information relating such non-chemical stressors to health effects and incorporating them into cumulative assessment has been the lack of analytical tools to easily and quantitatively monitor the cumulative exposure to combined effects of stressors over the life course. PMID:27534725

  8. Morphological traits associated with weed-suppressive ability of winter wheat against Italian ryegrass

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed-suppressive wheat (Triticum aestivum L.) cultivars have been suggested as a complement to chemical and cultural methods of weed control. The objectives of this study were to assess the range of weed-suppressive ability against Italian ryegrass [Lolium perenne L. ssp. multiflorum (Lam.) Husnot] ...

  9. Management filters and species traits: Weed community assembly in long-term organic and conventional systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Community assembly theory provides a useful framework to assess the response of weed communities to agricultural management systems and to improve the predictive power of weed science. Under this framework, weed community assembly is constrained by abiotic and biotic "filters" that act on species tr...

  10. Comparing digital software to human observation for estimating weed cover in nursery containers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Researchers who study weed management in nursery crops often rely on visual ratings to assess weed growth in response to some treatment effect. Visual weed ratings are easy to perform, non-destructive, and do not require any special equipment. However, visual ratings are prone to bias and skewed j...

  11. Genomics for Weed Science

    PubMed Central

    Horvath, David

    2010-01-01

    Numerous genomic-based studies have provided insight to the physiological and evolutionary processes involved in developmental and environmental processes of model plants such as arabidopsis and rice. However, far fewer efforts have been attempted to use genomic resources to study physiological and evolutionary processes of weedy plants. Genomics-based tools such as extensive EST databases and microarrays have been developed for a limited number of weedy species, although application of information and resources developed for model plants and crops are possible and have been exploited. These tools have just begun to provide insights into the response of these weeds to herbivore and pathogen attack, survival of extreme environmental conditions, and interaction with crops. The potential of these tools to illuminate mechanisms controlling the traits that allow weeds to invade novel habitats, survive extreme environments, and that make weeds difficult to eradicate have potential for both improving crops and developing novel methods to control weeds. PMID:20808523

  12. Weeds of the South

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Because there is no comprehensive weed identification manual for the southeastern U.S.A., a book was compiled to include accepted nomenclature, synonyms, descriptions, life history, special identifying characteristics, habitat preference, toxicity information, distribution maps, grass collar region ...

  13. Transdisciplinary weed research: new leverage on challenging weed problems?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Transdisciplinary Weed Research (TWR) is a promising path to more effective management of challenging weed problems. We define TWR as an integrated process of inquiry and action that addresses complex weed problems in the context of broader efforts to improve economic, environmental and social aspec...

  14. Grass and weed killer poisoning

    MedlinePlus

    Weedoff poisoning; Roundup poisoning ... Glyphosate is the poisonous ingredient in some weed killers. ... Glyphosate is in weed killers with these brand names: Roundup Bronco Glifonox Kleen-up Rodeo Weedoff Other ...

  15. Integrated Weed Management in Mint

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weeds lower mint oil quality and quantity and should be managed to maximize profits. Integrated weed management includes the use of cultural practices and other methods, such as herbicides. Planting healthy mint rhizomes free of weeds, insects, nematodes, and plant pathogens, and maintaining a heal...

  16. Rolled-crimped winter rye cover effects on hand-weeding times and fruit yield and quality of cucurbits

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fruit and vegetables produced without pesticides are in demand by some segments of society. However, weeds often are deleterious in such crops, and managing them without herbicides is difficult. Stale seedbeds and rolled-crimped winter rye cover crops are non-chemical methods that may help manage we...

  17. WEEDING IN TRANSGENES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Transgenes promise to reduce insecticide and fungicide use, but relatively little has been done to significantly reduce herbicide use through genetic engineering. Three strategies for transgene utilization are discussed which have the potential to change this: 1) improvement of weed-specific biocon...

  18. A Weed Cantilever

    ERIC Educational Resources Information Center

    Keller, Elhannan L.; Padalino, John

    1977-01-01

    Describes the Environmental Action Task activity, which may be used as a recreational game or an environmental perception experience, may be conducted indoors or out-of-doors, using weed stems (or spaghetti) and masking tape to construct a cantilever. Small groups of children work together to make the cantilever with the longest arm. Further…

  19. Weed Research in Mint

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weeds present in peppermint and spearmint reduce mint oil yield and quality. Flumioxazin combinations with clomazone and pendimethalin applied to dormant peppermint controlled prickly lettuce and flixweed without significant injury to the crop. Low rates of flumioxazin and sulfentrazone applied imm...

  20. Controlling Landscape Weeds.

    ERIC Educational Resources Information Center

    Nuss, James Robert, Jr.

    This agriculture extension service publication from Pennsylvania State University discusses the control of common grass and broadleaf weeds through the use of mulches and herbicides. The section on mulches discusses the different types of mulching materials, their advantages and disadvantages, herbicide-mulch combinations, and lists source of…

  1. Biotechnology in weed control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biotechnology can be used to enhance the management of weeds in several ways. Crops have been made resistant to herbicides by inserting transgenes that impart herbicide resistance into the plant genome. Glyphosate and glufosinate-resistant crops are commercialized in North America and crops made res...

  2. Weed Identification and Control in Vegetable Crops.

    ERIC Educational Resources Information Center

    Ferretti, Peter A., Comp.

    This agriculture extension service publication from Pennsylvania State University examines weed control and identification in vegetable crops. Contents include: (1) Types of weeds; (2) Reducing losses caused by weeds, general control methods and home garden weed control; (3) How herbicides are used; (4) Specific weeds in vegetable plantings; and…

  3. Quantifying temporal isolation: a modelling approach assessing the effect of flowering time differences on crop-to-weed pollen flow in sunflower

    PubMed Central

    Roumet, Marie; Cayre, Adeline; Latreille, Muriel; Muller, Marie-Hélène

    2015-01-01

    Flowering time divergence can be a crucial component of reproductive isolation between sympatric populations, but few studies have quantified its actual contribution to the reduction of gene flow. In this study, we aimed at estimating pollen-mediated gene flow between cultivated sunflower and a weedy conspecific sunflower population growing in the same field and at quantifying, how it is affected by the weeds' flowering time. For that purpose, we extended an existing mating model by including a temporal distance (i.e. flowering time difference between potential parents) effect on mating probabilities. Using phenological and genotypic data gathered on the crop and on a sample of the weedy population and its offspring, we estimated an average hybridization rate of approximately 10%. This rate varied strongly from 30% on average for weeds flowering at the crop flowering peak to 0% when the crop finished flowering and was affected by the local density of weeds. Our result also suggested the occurrence of other factors limiting crop-to-weed gene flow. This level of gene flow and its dependence on flowering time might influence the evolutionary fate of weedy sunflower populations sympatric to their crop relative. PMID:25667603

  4. Quantifying temporal isolation: a modelling approach assessing the effect of flowering time differences on crop-to-weed pollen flow in sunflower.

    PubMed

    Roumet, Marie; Cayre, Adeline; Latreille, Muriel; Muller, Marie-Hélène

    2015-01-01

    Flowering time divergence can be a crucial component of reproductive isolation between sympatric populations, but few studies have quantified its actual contribution to the reduction of gene flow. In this study, we aimed at estimating pollen-mediated gene flow between cultivated sunflower and a weedy conspecific sunflower population growing in the same field and at quantifying, how it is affected by the weeds' flowering time. For that purpose, we extended an existing mating model by including a temporal distance (i.e. flowering time difference between potential parents) effect on mating probabilities. Using phenological and genotypic data gathered on the crop and on a sample of the weedy population and its offspring, we estimated an average hybridization rate of approximately 10%. This rate varied strongly from 30% on average for weeds flowering at the crop flowering peak to 0% when the crop finished flowering and was affected by the local density of weeds. Our result also suggested the occurrence of other factors limiting crop-to-weed gene flow. This level of gene flow and its dependence on flowering time might influence the evolutionary fate of weedy sunflower populations sympatric to their crop relative. PMID:25667603

  5. INTEGRATED WEED CONTROL IN MAIZE.

    PubMed

    Latré, J; Dewitte, K; Derycke, V; De Roo, B; Haesaert, G

    2015-01-01

    Integrated pest management has been implemented as a general practice by EU legislation. As weed control actually is the most important crop protection measure in maize for Western Europe, the new legislation will have its impact. The question is of course which systems can be successfully implemented in practice with respect to labour efficiency and economical parameters. During 3 successive growing seasons (2007, 2008, 2009) weed control in maize was evaluated, the main focus was put on different techniques of integrated weed control and was compared with chemical weed control. Additionally, during 4 successive growing seasons (2011, 2012, 2013 and 2014) two objects based on integrated weed control and two objects based on mechanical weed control were compared to about twenty different objects of conventional chemical weed control. One of the objects based on mechanical weed control consisted of treatment with the flex-tine harrow before and after emergence in combination with chemical weed control at a reduced rate in 3-4 leave stage. The second one consisted of broadcast mechanical treatments before and after emergence followed by a final in-row application of herbicides and an inter-row cultivation at 6-7(8) leave stage. All trials were conducted on the Experimental farm of Bottelare HoGent-UGent on a sandy loam soil. Maize was growing in 1/3 crop rotation. The effect on weed growth as well as the economic impact of the different applications was evaluated. Combining chemical and mechanical weed control is a possible option in conventional farming but the disadvantages must be taken into account. A better planned weed control based on the real present weed-population in combination with a carefully thought-out choice of herbicides should also be considered as an IPM--approach. PMID:27145588

  6. Spatio-temporal variations of aquatic weeds abundance and coverage in Lake Chivero, Zimbabwe

    NASA Astrophysics Data System (ADS)

    Shekede, M. D.; Kusangaya, S.; Schmidt, K.

    Information on the spatial distribution of aquatic weeds is required for understanding the evolution of weed invasion and propagation rates. Such information is also vital for identifying affected areas and relating weed abundance to probable changes in environmental conditions and human actions including management practices within the lake and its catchment. Information on aquatic weed distribution also assists in evaluating the effectiveness of control measures and management actions. In Zimbabwe, Lake Chivero has been characterised by aquatic weed proliferation since the 1970s. Field surveys done between December 2005 and March 2006 showed concentrations of 1.2 mg/l and 0.3 mg/l up from 0.3 mg/l and 0.03 mg/l in 2001 for phosphates and nitrates respectively. Proliferation of aquatic weeds will continue unless nutrient loadings to this lake are reduced. The aim of this paper was to assess the feasibility of mapping the spatial extent and abundance of aquatic weeds in Lake Chivero, Zimbabwe using Landsat images. Landsat images of 1976, 1989 and 2000 were used to calculate the normalised difference vegetation index (NDVI) which was used for estimating the spatial extent of aquatic weeds and weed biomass. Field data and actual biomass measurements were obtained between December 2005 and March 2006 by harvesting weeds from the lake. This was subsequently related to NDVI and used to estimate the abundance of the different weed species. The results indicate that the weed coverage in Lake Chivero declined from 42% in 1976, 36% in 1989 to 22% in 2000. The research also demonstrated that Typha capensis has more biomass, 11.1kg per square metre, than any other weed type and hence higher abundance in all the years. It was concluded that remote sensing is an invaluable asset for detection of invasions, assessment of infestation levels, monitoring rate of spread, and determining the efficacy of weed mitigation measures.

  7. Combined impact of lead, cadmium, polychlorinated biphenyls and non-chemical risk factors on blood pressure in NHANES

    SciTech Connect

    Peters, Junenette L. Patricia Fabian, M. Levy, Jonathan I.

    2014-07-15

    High blood pressure is associated with exposure to multiple chemical and non-chemical risk factors, but epidemiological analyses to date have not assessed the combined effects of both chemical and non-chemical stressors on human populations in the context of cumulative risk assessment. We developed a novel modeling approach to evaluate the combined impact of lead, cadmium, polychlorinated biphenyls (PCBs), and multiple non-chemical risk factors on four blood pressure measures using data for adults aged ≥20 years from the National Health and Nutrition Examination Survey (1999–2008). We developed predictive models for chemical and other stressors. Structural equation models were applied to account for complex associations among predictors of stressors as well as blood pressure. Models showed that blood lead, serum PCBs, and established non-chemical stressors were significantly associated with blood pressure. Lead was the chemical stressor most predictive of diastolic blood pressure and mean arterial pressure, while PCBs had a greater influence on systolic blood pressure and pulse pressure, and blood cadmium was not a significant predictor of blood pressure. The simultaneously fit exposure models explained 34%, 43% and 52% of the variance for lead, cadmium and PCBs, respectively. The structural equation models were developed using predictors available from public data streams (e.g., U.S. Census), which would allow the models to be applied to any U.S. population exposed to these multiple stressors in order to identify high risk subpopulations, direct intervention strategies, and inform public policy. - Highlights: • We evaluated joint impact of chemical and non-chemical stressors on blood pressure. • We built predictive models for lead, cadmium and polychlorinated biphenyls (PCBs). • Our approach allows joint evaluation of predictors from population-specific data. • Lead, PCBs and established non-chemical stressors were related to blood pressure.

  8. Invasive Weed Management Is Site-Specific Weed Management.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Site-specific weed management in crops and invasive weed management in natural lands and rangelands appear to be unrelated research areas but there are many connections in the research problems, approaches and solutions. An obvious link is technology. The technology of precision agriculture - GPS, ...

  9. Weed Identification Field Training Demonstrations.

    ERIC Educational Resources Information Center

    Murdock, Edward C.; And Others

    1986-01-01

    Reviews efforts undertaken in weed identification field training sessions for agriprofessionals in South Carolina. Data over a four year period (1980-1983) revealed that participants showed significant improvement in their ability to identify weeds. Reaffirms the value of the field demonstration technique. (ML)

  10. Organic weed control in watermelons

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Integrated pest management (IPM) is an essential element for certified organic crop production and producers place weed control as their highest research priority within their IPM programs. The objective of these experiments was to investigate the impact of integrated organic weed control systems o...

  11. Parasitic Weeds, a Scientific Challenge

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A recent issue of the SCI journal Pest Management Science (May, 2009) was devoted to an overview of the problem of parasitic weeds and to the research that is being done to alleviate it. These papers are from an OECD-sponsored conference entitled Managing Parasitic Weeds that recently brought the b...

  12. Control of aquatic weeds through pollutant reduction and weed utilization: a weed management approach in the lower Kafue River of Zambia

    NASA Astrophysics Data System (ADS)

    Sinkala, Thomson; Mwase, Enala T.; Mwala, Mick

    The aquatic weed situation in the Kafue River in Zambia continues to be a major challenge to the sustainable utilization of the water resources of the river. The general methods for managing the weeds, especially the water hyacinth, include use of bio-agents, chemicals, mechanical and physical approaches. These have had very little impact. This paper reports on a project that is investigating weed management strategies which involve use of cleaner production (CP) approach and the utilization of the weed for economic purposes. In addition, the ecological implications of these methods are being assessed. Effluent assessments indicated that apart from nitrates and phosphates, other effluent parameters met the Environmental Council of Zambia standards. Results further show that all the 24 areas surveyed for CP have uncontrolled socio-economic activities which generate both point and non-point sources of pollution that enter the water bodies. To minimize pollution, efforts include devising policy and technical strategies with the involvement of the affected riparian community. Production of mushroom by the communities using the water hyacinth substrate has been demonstrated. Up to 2.1 kg of mushroom was harvested from a single flush over a period of 4-5 weeks. Vegetables grown on soils treated with water hyacinth manure performed better than those grown using commercial fertiliser. The economics of the production are however, yet to be confirmed. If weed usage is proven economically and ecologically viable, the riverine community is envisaged to play a big role in aquatic weed management. High numbers of invertebrates known to be sensitive to pollution have been recorded in the weed-infested Kafue River implying that the water is of “good” quality for these aquatic invertebrates. This observed quality of water may be due to water hyacinth playing a role by sieving pollutants from the river.

  13. NON-CHEMICAL IMPACTS (SYSTEMS ANALYSIS BRANCH, SUSTAINABLE TECHNOLOGY DIVISION, NRMRL)

    EPA Science Inventory

    Non-chemical ecological impacts include those that are caused by physical or biological disturbances. Non-chemical stressors identified by SETAC include ionizing radiation, heat, noise, environmental disturbances (habitat alteration, including changes to biochemical cycling, biod...

  14. Managing weeds in potato rotations without herbicides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Managing weeds without herbicides requires an integration of methods and strategies and a change in how weeds are perceived. Weeds should be managed in a holistic, intentional and proactive manner. Successful weed management in organic systems attempts to understand the interactions between the crop...

  15. Applicator Training Manual for: Aquatic Weed Control.

    ERIC Educational Resources Information Center

    Herron, James W.

    The aquatic weeds discussed in this manual include algae, floating weeds, emersed weeds, and submerged weeds. Specific requirements for pesticide application are given for static water, limited flow, and moving water situations. Secondary effects of improper application rates and faulty application are described. Finally, techniques of limited…

  16. 7 CFR 201.15 - Weed seeds.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 false Weed seeds. 201.15 Section 201.15 Agriculture... REGULATIONS Labeling Agricultural Seeds § 201.15 Weed seeds. The percentage of weed seeds shall include seeds of plants considered weeds in the State into which the seed is offered for transportation...

  17. 7 CFR 201.15 - Weed seeds.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 3 2014-01-01 2014-01-01 false Weed seeds. 201.15 Section 201.15 Agriculture... REGULATIONS Labeling Agricultural Seeds § 201.15 Weed seeds. The percentage of weed seeds shall include seeds of plants considered weeds in the State into which the seed is offered for transportation...

  18. 7 CFR 201.50 - Weed seed.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 3 2014-01-01 2014-01-01 false Weed seed. 201.50 Section 201.50 Agriculture... REGULATIONS Purity Analysis in the Administration of the Act § 201.50 Weed seed. Seeds (including bulblets or tubers) of plants shall be considered weed seeds when recognized as weed seeds by the law or rules...

  19. 7 CFR 201.50 - Weed seed.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 false Weed seed. 201.50 Section 201.50 Agriculture... REGULATIONS Purity Analysis in the Administration of the Act § 201.50 Weed seed. Seeds (including bulblets or tubers) of plants shall be considered weed seeds when recognized as weed seeds by the law or rules...

  20. 7 CFR 201.50 - Weed seed.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Weed seed. 201.50 Section 201.50 Agriculture... REGULATIONS Purity Analysis in the Administration of the Act § 201.50 Weed seed. Seeds (including bulblets or tubers) of plants shall be considered weed seeds when recognized as weed seeds by the law or rules...

  1. 7 CFR 201.50 - Weed seed.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 3 2012-01-01 2012-01-01 false Weed seed. 201.50 Section 201.50 Agriculture... REGULATIONS Purity Analysis in the Administration of the Act § 201.50 Weed seed. Seeds (including bulblets or tubers) of plants shall be considered weed seeds when recognized as weed seeds by the law or rules...

  2. Weeding the School Library Media Collection.

    ERIC Educational Resources Information Center

    School Library Media Quarterly, 1984

    1984-01-01

    This document prepared by Calgary Board of Education, Calgary, Alberta, Canada, discusses a systematic approach to strengthening the library media collection. A statement of principle, what to weed, specific guides to weeding (by Dewey Decimal classification and type of material), what not to weed, procedures, and weeding follow-up are…

  3. 7 CFR 201.15 - Weed seeds.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Weed seeds. 201.15 Section 201.15 Agriculture... REGULATIONS Labeling Agricultural Seeds § 201.15 Weed seeds. The percentage of weed seeds shall include seeds of plants considered weeds in the State into which the seed is offered for transportation...

  4. 7 CFR 201.50 - Weed seed.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Weed seed. 201.50 Section 201.50 Agriculture... REGULATIONS Purity Analysis in the Administration of the Act § 201.50 Weed seed. Seeds (including bulblets or tubers) of plants shall be considered weed seeds when recognized as weed seeds by the law or rules...

  5. 7 CFR 201.15 - Weed seeds.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 3 2012-01-01 2012-01-01 false Weed seeds. 201.15 Section 201.15 Agriculture... REGULATIONS Labeling Agricultural Seeds § 201.15 Weed seeds. The percentage of weed seeds shall include seeds of plants considered weeds in the State into which the seed is offered for transportation...

  6. 7 CFR 201.15 - Weed seeds.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Weed seeds. 201.15 Section 201.15 Agriculture... REGULATIONS Labeling Agricultural Seeds § 201.15 Weed seeds. The percentage of weed seeds shall include seeds of plants considered weeds in the State into which the seed is offered for transportation...

  7. A new perspective with weed management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    No-till cropping systems are increasing land productivity. Herbicides are a crucial tool for weed management in no-till, but weed resistance is decreasing control efficacy and increasing input costs. Producers are seeking a broader perspective with weed management. One approach is to disrupt weed...

  8. Annual Weeds, Alternative Crops for Alternative Fuel

    Technology Transfer Automated Retrieval System (TEKTRAN)

    All cropland acreage in Alabama is infested with one or more species of annual weeds. Weeds are estimated to cost producers in the state approximately 8% of their potential yield, even with the current weed control technology available. Weed management continues to be the most expensive row crop pr...

  9. Occurrence of trends of weed seed and pathogen contaminants in bentgrass seed lots in Oregon

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nearly all of the bentgrass seed grown in the United States is produced in Oregon. However, little is known about the occurrence of weed seed or pathogen propagule contaminants in bentgrass seed lots. This study was conducted to assess the diversity and frequency of occurrence of weed seeds, ergot (...

  10. Susceptibility of several common subtropical weeds to Meloidogyne incognita, M. arenaria, and M. javanica

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Experiments were conducted in the greenhouse to assess galling and egg production of three root-knot nematode species, Meloidogyne incognita, M. arenaria, and M. javanica, on several weeds common to Florida agricultural land. Weeds evaluated were Amaranthus retroflexus (redroot pigweed), Aeschynomen...

  11. Cultural practices in cotton (Gossypium hirsutum) affect weed seed production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Billions of dollars are lost annually due to weeds or weed control, but weeds persist. Successful weed management systems must reduce weed populations. The objectives of this research were to 1) determine if cotton row spacing has an impact on weed growth and seed production and 2) evaluate the infl...

  12. 13Carbon isotope discrimination in roots and shoots of major weed species of southern U.S. rice fields and its potential use for analysis of rice-weed root interactions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Assessing below ground plant interference in rice has been difficult in the past because thorough, accurate separation of the intertwined roots of weed and crop is extremely challenging. A d13C depletion method has been developed to assess interactions between roots of barnyardgrass and weed-suppre...

  13. Sweet corn hybrid tolerance to weed competition under three weed management levels

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nearly all commercial sweet corn fields contain weeds that escaped management and often suffer yield loss due to weed competition. Field trials were conducted from 2009 to 2011 near Prosser, WA and Urbana, IL to evaluate weed response and tolerance of four sweet corn hybrids to three levels of weed...

  14. Sweet Corn Hybrid Tolerance to Weed Competition under Three Weed Management Levels

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nearly all commercial sweet corn fields contain weeds that escaped management and often suffer yield loss due to weed competition. Field trials were conducted from 2009 to 2011 near Prosser, WA and Urbana, IL to evaluate weed response and tolerance of four sweet corn hybrids to three levels of weed...

  15. A weed control program for establishing lesquerella

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Broad spectrum weed control is essential for successful lesquerella [Lesquerella fendleri (Gray) Wats., Brassicaceae] production. Weeds must be controlled during establishment and throughout the growing season. Lesquerella seedlings grow slowly following germination and emergence, and cannot compe...

  16. Response of Two Sweet Potato Cultivars to Weed Interference

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field experiments were conducted at Charleston, SC to assess the effect of different durations of weed interference on two sweetpotato cultivars with distinctly different shoot growth habits. The cultivars were Beauregard, which has a spreading growth habit, and Carolina Bunch, which has an erect g...

  17. Weed control options for transplanted onions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As interest in sweet onion production has grown in Oklahoma and Arkansas, so has the realization that uncontrolled weeds can result in a total loss of marketable onion production. Although mechanical weed control can successfully control weeds between rows, producers need reliable methods for contro...

  18. Managing weeds with a population dynamics approach

    Technology Transfer Automated Retrieval System (TEKTRAN)

    No-till cropping systems are increasing land productivity. A critical aspect of no-till is controlling weeds. Herbicides are a crucial tool for weed management, but weed resistance is decreasing control efficacy and increasing input costs. Scientists and producers are seeking a broader perspectiv...

  19. Cover Crop Effects on Weed Management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weeds are often the most common and costly pests in vegetable production, especially in organic production systems. Weeds that germinate during cover cropping and produce seeds will increase the weed seedbank and may increase production costs. This chapter discusses the effect of cultural practices ...

  20. Weed control efficacy with Racer (ammonium nonanoate)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed control is a major challenge in conventional and organic production systems. Agricultural weed control costs the U.S. economy more than the cost of insect and disease control combined. Organic vegetable producers have many challenges since their weed control tools are mostly limited to cultur...

  1. What's a Weed? Knowledge, Attitude and Behaviour of Park Visitors about Weeds.

    PubMed

    Ansong, Michael; Pickering, Catherine

    2015-01-01

    Weeds are a major threat to biodiversity globally degrading natural areas of high conservation value. But what are our attitudes about weeds and their management including weeds in national parks? Do we know what a weed is? Do we consider weeds a problem? Do we support their management? Are we unintentionally spreading weeds in parks? To answer these questions, we surveyed visitors entering a large popular national park near the city of Brisbane, Australia. Park visitors were knowledgeable about weeds; with >75% correctly defining weeds as 'plants that grow where they are not wanted'. About 10% of the visitors, however, provided their own sophisticated definitions. This capacity to define weeds did not vary with people's age, sex or level of education. We constructed a scale measuring visitors' overall concern about weeds in parks using the responses to ten Likert scale statements. Over 85% of visitors were concerned about weeds with older visitors, hikers, and those who could correctly define weeds more concerned than their counterparts. The majority think visitors unintentionally introduce seeds into parks, with many (63%) having found seeds on their own clothing. However, over a third disposed of these seeds in ways that could facilitate weed spread. Therefore, although most visitors were knowledgeable and concerned about weeds, and support their control, there is a clear need for more effective communication regarding the risk of visitors unintentionally dispersing weed seeds in parks. PMID:26252004

  2. What’s a Weed? Knowledge, Attitude and Behaviour of Park Visitors about Weeds

    PubMed Central

    Ansong, Michael; Pickering, Catherine

    2015-01-01

    Weeds are a major threat to biodiversity globally degrading natural areas of high conservation value. But what are our attitudes about weeds and their management including weeds in national parks? Do we know what a weed is? Do we consider weeds a problem? Do we support their management? Are we unintentionally spreading weeds in parks? To answer these questions, we surveyed visitors entering a large popular national park near the city of Brisbane, Australia. Park visitors were knowledgeable about weeds; with >75% correctly defining weeds as ‘plants that grow where they are not wanted’. About 10% of the visitors, however, provided their own sophisticated definitions. This capacity to define weeds did not vary with people’s age, sex or level of education. We constructed a scale measuring visitors’ overall concern about weeds in parks using the responses to ten Likert scale statements. Over 85% of visitors were concerned about weeds with older visitors, hikers, and those who could correctly define weeds more concerned than their counterparts. The majority think visitors unintentionally introduce seeds into parks, with many (63%) having found seeds on their own clothing. However, over a third disposed of these seeds in ways that could facilitate weed spread. Therefore, although most visitors were knowledgeable and concerned about weeds, and support their control, there is a clear need for more effective communication regarding the risk of visitors unintentionally dispersing weed seeds in parks. PMID:26252004

  3. Using weeds to fight wastes

    SciTech Connect

    1992-10-01

    Researchers at Los Alamos National Laboratory and New Mexico State University have discovered that jimson weed and wild tomato plants can remove the toxic wastes in wastewater associated with the production of trinitrotoluene (TNT). According to Wolfgang F. Mueller of New Mexico State, tissue-cultured cells of jimson weed rapidly absorb and break down toxic and carcinogenic elements in {open_quotes}pink water,{close_quotes} a by-product of the manufacture of TNT. Mueller and his colleagues have found similar results with the wild tomato plant.

  4. Exposure to Chemical and Non-Chemical Stressors in Vulnerable Groups and Potential Health Impacts

    EPA Science Inventory

    Exposures to chemical stressors Understanding of the myriad non-chemical stressorsLinkages between chemical and non-chemical stressors and health and well-beingPriority research in children’s environmental health, Tribal research needs, and disproportionately impacted comm...

  5. Genomics and Weeds: A Synthesis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genomics can be used to solve many problems associated with the management of weeds. New target sites for herbicides have been discovered through functional genomic approaches to determine gene function. Modes of action of herbicides can be clarified or discovered by transcriptome analysis. Under...

  6. Weed Biocontrol in Landscape Restoration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed biological control programs in natural areas are often undertaken with the goal of restoring native plant communities and/or ecosystem services to a pre-invasion level. These objectives may be achieved in some areas with biological control alone; however, in other sites integration of biologica...

  7. CLASSICAL BIOLOGICAL CONTROL OF WEEDS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Classical biological control of weeds is an important tool for managing invasive alien plants that have become too widespread to control by conventional methods. It involves the discovery and release of naturally occurring species of natural enemies (insects, mites or pathogens) to control a pest (...

  8. Weed biocontrol in landscape restoration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed biological control programs in natural areas are often undertaken with the goal of restoring native plant communities and/or ecosystem services to a pre-invasion level. These objectives may be achieved in some areas with biological control alone; however, in other sites integration of biologica...

  9. Ground-Based Sensing System for Weed Mapping in Cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A ground-based weed mapping system was developed to measure weed intensity and distribution in a cotton field. The weed mapping system includes WeedSeeker® PhD600 sensor modules to indicate the presence of weeds between rows, a GPS receiver to provide spatial information, and a data acquisition and ...

  10. Preemergence herbicides affect critical period of weed control in cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Effective weed control systems must eliminate emerged weeds as well as account for subsequent weed emergence. Two common questions associated with herbicide control are: 1) how long can weeds compete with a crop for resources before yield is reduced and 2) when do weeds that emerge late in the seaso...

  11. Weed Dynamics during Transition to Conservation Agriculture in Western Kenya Maize Production

    PubMed Central

    Odhiambo, Judith A.; Norton, Urszula; Ashilenje, Dennis; Omondi, Emmanuel C.; Norton, Jay B.

    2015-01-01

    Weed competition is a significant problem in maize (Zea mays, L.) production in Sub-Saharan Africa. Better understanding of weed management and costs in maize intercropped with beans (Phaseolus vulgaris, L.) during transition to conservation agricultural systems is needed. Changes in weed population and maize growth were assessed for a period of three years at Bungoma where crops are grown twice per year and at Trans-Nzoia where crops are grown once per year. Treatments included three tillage practices: minimum (MT), no-till (NT) and conventional (CT) applied to three cropping systems: continuous maize/bean intercropping (TYPICAL), maize/bean intercropping with relayed mucuna after bean harvest (RELAY) and maize, bean and mucuna planted in a strip intercropping arrangement (STRIP). Herbicides were used in NT, shallow hand hoeing and herbicides were used in MT and deep hoeing with no herbicides were used in CT. Weed and maize performance in the maize phase of each cropping system were assessed at both locations and costs of weed control were estimated at Manor House only. Weed density of grass and forb species declined significantly under MT and NT at Manor House and of grass species only at Mabanga. The greatest declines of more than 50% were observed as early as within one year of the transition to MT and NT in STRIP and TYPICAL cropping systems at Manor House. Transitioning to conservation based systems resulted in a decline of four out of five most dominant weed species. At the same time, no negative impact of MT or NT on maize growth was observed. Corresponding costs of weed management were reduced by $148.40 ha-1 in MT and $149.60 ha-1 in NT compared with CT. In conclusion, farmers can benefit from effective and less expensive weed management alternatives early in the process of transitioning to reduced tillage operations. PMID:26237404

  12. Weed Dynamics during Transition to Conservation Agriculture in Western Kenya Maize Production.

    PubMed

    Odhiambo, Judith A; Norton, Urszula; Ashilenje, Dennis; Omondi, Emmanuel C; Norton, Jay B

    2015-01-01

    Weed competition is a significant problem in maize (Zea mays, L.) production in Sub-Saharan Africa. Better understanding of weed management and costs in maize intercropped with beans (Phaseolus vulgaris, L.) during transition to conservation agricultural systems is needed. Changes in weed population and maize growth were assessed for a period of three years at Bungoma where crops are grown twice per year and at Trans-Nzoia where crops are grown once per year. Treatments included three tillage practices: minimum (MT), no-till (NT) and conventional (CT) applied to three cropping systems: continuous maize/bean intercropping (TYPICAL), maize/bean intercropping with relayed mucuna after bean harvest (RELAY) and maize, bean and mucuna planted in a strip intercropping arrangement (STRIP). Herbicides were used in NT, shallow hand hoeing and herbicides were used in MT and deep hoeing with no herbicides were used in CT. Weed and maize performance in the maize phase of each cropping system were assessed at both locations and costs of weed control were estimated at Manor House only. Weed density of grass and forb species declined significantly under MT and NT at Manor House and of grass species only at Mabanga. The greatest declines of more than 50% were observed as early as within one year of the transition to MT and NT in STRIP and TYPICAL cropping systems at Manor House. Transitioning to conservation based systems resulted in a decline of four out of five most dominant weed species. At the same time, no negative impact of MT or NT on maize growth was observed. Corresponding costs of weed management were reduced by $148.40 ha(-1) in MT and $149.60 ha(-1) in NT compared with CT. In conclusion, farmers can benefit from effective and less expensive weed management alternatives early in the process of transitioning to reduced tillage operations. PMID:26237404

  13. Accuracy and Feasibility of Optoelectronic Sensors for Weed Mapping in Wide Row Crops

    PubMed Central

    Andújar, Dionisio; Ribeiro, Ángela; Fernández-Quintanilla, César; Dorado, José

    2011-01-01

    The main objectives of this study were to assess the accuracy of a ground-based weed mapping system that included optoelectronic sensors for weed detection, and to determine the sampling resolution required for accurate weed maps in maize crops. The optoelectronic sensors were located in the inter-row area of maize to distinguish weeds against soil background. The system was evaluated in three maize fields in the early spring. System verification was performed with highly reliable data from digital images obtained in a regular 12 m × 12 m grid throughout the three fields. The comparison in all these sample points showed a good relationship (83% agreement on average) between the data of weed presence/absence obtained from the optoelectronic mapping system and the values derived from image processing software (“ground truth”). Regarding the optimization of sampling resolution, the comparison between the detailed maps (all crop rows with sensors separated 0.75 m) with maps obtained with various simulated distances between sensors (from 1.5 m to 6.0 m) indicated that a 4.5 m distance (equivalent to one in six crop rows) would be acceptable to construct accurate weed maps. This spatial resolution makes the system cheap and robust enough to generate maps of inter-row weeds. PMID:22163740

  14. Integration of herbicides with manual weeding for controlling the weeds in rice under saline environment.

    PubMed

    Hakim, M A; Juraimi, Abdul Shukor; Hanafi, M M; Rafii, Mohd Y; Ismail, Mohd Razi; Karim, S M Rezaul; Kausar, H

    2015-11-01

    The pot experiment was conducted to select appropriate integrated weed management method in rice under different salinity levels (0, 4 and 8 dS m(-1)). All the parameters including rice and weed measured were significantly influenced by weed control treatments at all salinity levels. Treatments including weed-free condition, Pretilachlor @0.375 kg ai ha(-1) + hand weeding, Propanil + Thiobencarb @ 0.9 kg ai ha(-1) and 1.8 kg ai ha(-1)+ hand weeding performed better under all salinity levels. Pretilachlor @ 0.375 kg ai ha(-1) with one round of hand weeding and propanil + thiobencarb 0.9 kg ai ha(-1) + 1.8 kg ai ha(-1) with one round of hand weeding were comparable to weed-free yields, and were superior to other treatments under salinity condition. Considering all the parameters, pretilachlor @ 0.375 kg ai ha(-1) + one round of hand weeding (at 65 DAT), propanil + thiobencarb 0.9 kg ai ha(-1) +1.8 kg ai ha(-1) + one round of hand weeding (at 65 DAT) gave the most effective control of weeds in rice under saline environments. PMID:26688966

  15. WEED COMMUNITY COMPOSTION IN RESPONSE TO ORGANIC AND CONVENTIONAL WEED CONTROL PRACTICES IN A CALIFORNIA VINEYARD

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Integrated weed management (IWM) employs multiple tactics to control weed infestations, and can be useful in reducing problematic weeds. IWM in California vineyards typically involves the integration of post-emergence herbicides and pre-emergence herbicides, with less emphasis on incorporation of no...

  16. Weeding Is Not Just for Gardeners: A Case Study on Weeding a Reference Collection

    ERIC Educational Resources Information Center

    Lee, Marta

    2009-01-01

    Weeding a reference collection can be time consuming, a thankless job, and an endless task. It is a dusty job and can add to the librarian's workload. Weeding the collection can add to its currency and usability; plus it removes outdated materials. Periodically weeding allows librarians to remember what is in the collection and what can be removed…

  17. The importance of weeds in ethnopharmacology.

    PubMed

    Stepp, J R; Moerman, D E

    2001-04-01

    Tropical primary forest is often considered to be the most important habitat for traditional peoples to gather medicinal plants. However, the role of weeds, commonly found in disturbed areas, in traditional medicinal floras has been overlooked. Data are presented showing the significant representation of weeds in the medicinal floras of the Highland Maya in Chiapas, Mexico and in the medicinal flora of Native North Americans as a whole. The frequency with which weeds appear in these pharmacopoeias is significantly larger (P<0.0001) than what would be predicted by the frequency of weed species in general. Explanations based on human ecology and biochemical ecology are presented. PMID:11282438

  18. Nutrient absorbtion of weeds in maize.

    PubMed

    Lehoczky, E; Kismányoky, A; Nagy, P; Németh, T

    2008-01-01

    Our study was carried out in Hungary at Keszthely, in 2007. The effect of different cultivation methods: no-till drill, disk tillage, conventional tillage (ploughing) and five increasing N doses were studied on the weediness. The bi-factorial trial was arranged in split plot design with four replications. Crop rotation: winter wheat-winter wheat-maize-maize. The seeding of maize was 23rd of April in 2007. The weed survey was made with Balázs-Ujvárosi coenological method on the 17th of May. In the experiment were found 21 weed species. We collected all plants of every weed species by plots. The sample area was 1 m2. Furthermore five maize plants per plot were sampled on the 22nd of May. Maize was at 3-4 leaves stage. For reason of competition studies no herbicides were applied on sampling sites. The aerial parts of weeds and maize plants were collected, and the fresh and dry matter weight was measured. We analyzed in detail, the occurrence of weed species, and the biomass production of weeds in comparison with maize. The effect of different cultivation methods markedly demonstrated the weed cover, the number of perennial and annual weeds and the number of occurring weed species. PMID:19226848

  19. Broadleaf weed control in lima beans.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Broadleaf weeds are particularly troublesome in lima beans due to the long growing season which extends beyond the period in which soil residual herbicides provide control. Weeds reduce yield and quality of lima beans, reduce harvest efficiency, and increase incidence of white mold. A study was co...

  20. Post-directed weed control in squash

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic squash (Cucurbita pepo L.) producers need appropriate herbicides that can effectively provide season- long weed control. Research was conducted in southeast Oklahoma (Atoka County, Lane, OK) to determine the impact of a potential organic herbicide on weed control efficacy, crop injury, and ...

  1. Software Tools for Weed Seed Germination Modeling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The next generation of weed seed germination models will need to account for variable soil microclimate conditions. In order to predict this microclimate environment we have developed a suite of individual tools (models) that can be used in conjunction with the next generation of weed seed germinati...

  2. Yield advances in peanut - weed control effects

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Improvements in weed management are a contributing factor to advancements in peanut yield. Widespread use of vacuum planters and increased acceptance of narrow row patterns enhance weed control by lessening bareground caused by skips and promoting quick canopy closure. Cultivation was traditionall...

  3. Nutsedge ecology in plasticulture affects weed management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Purple nutsedge and yellow nutsedge are naturalized exotic invasive weeds that are the most troublesome weeds of vegetable crops in the southeast US. Tubers are the primary means of nutsedge reproduction. Effective management strategies must suppress nutsedge tuber production. Greenhouse studies eva...

  4. Scythe (pelargonic acid) weed control in squash

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic squash (Cucurbita pepo L.) producers need appropriate herbicides that can effectively provide season-long weed control. Research was conducted in southeast Oklahoma (Atoka County, Lane, OK) to determine the impact of a potential organic herbicide on weed control efficacy, crop injury, and y...

  5. Preemergence weed control in watermelon - Lane

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Watermelon is a major vegetable crop in Oklahoma. Weed control on this crop is crucial for commercial growers particularly as labor costs increase and availability of hoeing crews decrease. Weed infested fields can be a source of pest problems including insect and disease, in addition to the obvio...

  6. When Can You Weed an Unused Book?

    ERIC Educational Resources Information Center

    Ettelt, Harold

    A study was conducted in 1988 by a community college librarian who was seeking an objective guide for weeding unused library books. It was hypothesized that a book not used in a certain number of years would never be used. At the beginning of the study, no books had ever been weeded although the library had begun acquiring books in 1969. To test…

  7. Molecular biology approaches to weed management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Global climate change appears to be favorable for invasive weed development and spread because invasive species in general are proficient at succeeding in new environments. To worsen matters, herbicide-resistant weeds have become a severe threat in modern agricultural systems due to the extensive us...

  8. Weeding the Library Media Center Collections.

    ERIC Educational Resources Information Center

    Buckingham, Betty Jo

    These guidelines for weeding library media collections are addressed to elementary and secondary school library media centers and to community college and vocational school library resource centers in Iowa. The publication includes some philosophy about weeding, and specific guidelines are summarized in bold-faced type for ease of use. The…

  9. Weed competition and dry bean yield components

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed competition can significantly reduce dry bean (Phaseolus vulgaris L.) yields and therefore the profitability for the producer. Depending on the dry bean variety produced, the yield components may be affected differently by the stress produced by weed competition. This research was conducted to ...

  10. Fire Effects on Invasive Weed Seed Germination

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Restoring historic fire regimes is often beneficial to rangeland structure and function. However, understanding of interactions between fire and invasive weeds is limited. We designed an experiment to determine fire effects on germination of soil surface-deposited seeds of the invasive weeds Bromu...

  11. Socio-demographic characteristics of UK families using pesticides and weed-killers.

    PubMed

    Steer, Colin D; Grey, Charlotte N B

    2006-05-01

    Pesticides are widely used in the home and garden to kill insects, weeds and other unwanted pests. There is mounting evidence that this usage may also have health consequences particularly on children. Using the ALSPAC cohort of 13,391 families with self-reported usage data up to age 4 years of the study child, the main users of pesticides appeared to be older, Caucasian, better educated, have higher incomes and more likely to own their home or to belong to non-manual social classes compared to less frequent users. There was some suggestion that different factors may affect weed-killer compared to other pesticide use. In particular, income appeared unrelated to other pesticide use. This may reflect different attitudes to indoor compared to garden applications. Alternatively, it may reflect whether the main user was the mother or the partner. Some authorities are currently encouraging domestic users to consider other non-chemical means of pest control before using pesticides. These results may help in targeting particular groups if further reductions in pesticide usage are desired. They have also helped in identifying the important confounders for adjusting future analyses on the potential health consequences of pesticides and weed-killers. PMID:16132066

  12. POST weed control using halosulfuron in direct-seeded watermelon

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed control is needed in watermelon (Citrullus lanatus) production to avoid losses in crop yield and marketability that result from weed interference. Not only does weed control provide direct benefits to crop yields, but uncontrolled weeds hamper the management of insect and disease pests and redu...

  13. A survey of weeds and herbicides in Georgia Pecan

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A survey was conducted in 2012 in Georgia to determine the most troublesome weeds in pecan orchards and document common weed control practices using herbicides. Weed control practices and infestations in pecan were divided between winter and summer seasons. The most troublesome pecan winter weed s...

  14. Weed species shifts in glyphosate-resistant crops.

    PubMed

    Owen, Micheal D K

    2008-04-01

    The adoption of glyphosate-based crop production systems has been one of the most important revolutions in the history of agriculture. Changes in weed communities owing to species that do not respond to current glyphosate-based management tactics are rapidly increasing. Clearly, glyphosate-resistant crops (GRCs) do not influence weeds any more than non-transgenic crops. For most crops, the trait itself is essentially benign in the environment. Rather, the weed control tactics imposed by growers create the ecological selection pressure that ultimately changes the weed communities. This is seen in the adoption of conservation tillage and weed management programs that focus on one herbicide mode of action and have hastened several important weed population shifts. Tillage (disturbance) is one of the primary factors that affect changes in weed communities. The intense selection pressure from herbicide use will result in the evolution of herbicide-resistant weed biotypes or shifts in the relative prominence of one weed species in the weed community. Changes in weed communities are inevitable and an intrinsic consequence of growing crops over time. The glyphosate-based weed management tactics used in GRCs impose the selection pressure that supports weed population shifts. Examples of weed population shifts in GRCs include common waterhemp [Amaranthus tuberculatus (Moq ex DC) JD Sauer], horseweed (Conyza canadensis L), giant ragweed (Ambrosia trifida L) and other relatively new weed problems. Growers have handled these weed population shifts with varying success depending on the crop. PMID:18232055

  15. 7 CFR 201.16 - Noxious-weed seeds.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 false Noxious-weed seeds. 201.16 Section 201.16 Agriculture... REGULATIONS Labeling Agricultural Seeds § 201.16 Noxious-weed seeds. (a) Except for those kinds of noxious-weed seeds shown in paragraph (b) of this section, the names of the kinds of noxious-weed seeds and...

  16. 7 CFR 360.200 - Designation of noxious weeds.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 5 2012-01-01 2012-01-01 false Designation of noxious weeds. 360.200 Section 360.200... SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.200 Designation of noxious weeds. The Administrator has determined that it is necessary to designate the following plants 1 as noxious weeds...

  17. 7 CFR 201.16 - Noxious-weed seeds.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Noxious-weed seeds. 201.16 Section 201.16 Agriculture... REGULATIONS Labeling Agricultural Seeds § 201.16 Noxious-weed seeds. (a) Except for those kinds of noxious-weed seeds shown in paragraph (b) of this section, the names of the kinds of noxious-weed seeds and...

  18. 7 CFR 201.16 - Noxious-weed seeds.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 3 2014-01-01 2014-01-01 false Noxious-weed seeds. 201.16 Section 201.16 Agriculture... REGULATIONS Labeling Agricultural Seeds § 201.16 Noxious-weed seeds. (a) Except for those kinds of noxious-weed seeds shown in paragraph (b) of this section, the names of the kinds of noxious-weed seeds and...

  19. 7 CFR 201.16 - Noxious-weed seeds.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Noxious-weed seeds. 201.16 Section 201.16 Agriculture... REGULATIONS Labeling Agricultural Seeds § 201.16 Noxious-weed seeds. (a) Except for those kinds of noxious-weed seeds shown in paragraph (b) of this section, the names of the kinds of noxious-weed seeds and...

  20. Weed Garden: An Effective Tool for Extension Education

    ERIC Educational Resources Information Center

    Beck, Leslie; Patton, Aaron J.

    2015-01-01

    A weed garden was constructed to quantify and improve identification skills among clientele. The garden was planted with over 100 weed species based on surveys on problematic weeds. The weed garden proved useful for introducing additional hands-on learning activities into traditional lecture-based seminars. Through seminar and field day attendee…

  1. 7 CFR 360.200 - Designation of noxious weeds.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 5 2013-01-01 2013-01-01 false Designation of noxious weeds. 360.200 Section 360.200... SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.200 Designation of noxious weeds. The Administrator has determined that it is necessary to designate the following plants 1 as noxious weeds...

  2. 7 CFR 360.200 - Designation of noxious weeds.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 5 2014-01-01 2014-01-01 false Designation of noxious weeds. 360.200 Section 360.200... SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.200 Designation of noxious weeds. The Administrator has determined that it is necessary to designate the following plants 1 as noxious weeds...

  3. 7 CFR 201.16 - Noxious-weed seeds.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 3 2012-01-01 2012-01-01 false Noxious-weed seeds. 201.16 Section 201.16 Agriculture... REGULATIONS Labeling Agricultural Seeds § 201.16 Noxious-weed seeds. (a) Except for those kinds of noxious-weed seeds shown in paragraph (b) of this section, the names of the kinds of noxious-weed seeds and...

  4. "Digital Sampling": Mapping Weed Presence in Fallow Fields

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Growers need maps of the distribution of weeds in their fields to reduce herbicide use with site-specific weed management (SSWM). Remote sensing is key to successful weed mapping and sophisticated hyper- and multi-spectral image-based systems appear promising for detecting weed patches and identifyi...

  5. Multi-generational impacts of the psyllid Arytinnis hakani (Hemiptera: Psyllidae) on growth and survival of the invasive weed Genista monspessulana

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pre-release efficacy assessments can identify agents with the most potential to impact the target weed. Experiments typically occur within a single generation of the agent, however, and strong impacts on target weeds may take longer to emerge. This study examined the effects of the prospective agent...

  6. Meta-Analysis of the Chemical and Non-Chemical Stressors Affecting Childhood Obesity

    EPA Science Inventory

    Worldwide, approximately 42 million children under the age of 5 years are considered overweight or obese. While much research has focused on individual behaviors impacting obesity, little research has emphasized the complex interactions of numerous chemical and non-chemical stres...

  7. EBIPM 2013 planner for preventing weed invasion

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using a calendar format, this publication is designed for land managers to make management decisions for preventing weed invasions in a timely manner. For each month there are recommendations for wee prevention management actions....

  8. Using Weeds and Wildflowers to Study Plants.

    ERIC Educational Resources Information Center

    Nowak, Nancy

    1984-01-01

    Offers suggestions for activities in which local weeds and wildflowers are used to study a variety of topics. These topics include classification, ecological succession, and mapping. Also lists the types of experiments students can perform with these plants. (JN)

  9. Kyllinga, troublesome sedge weeds in turf

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Kyllinga sedges are troublesome weeds in turf, lawns, flowerbeds, seasonally wet right-of-ways, vegetable crops, nursery plantings, and container plants. Descriptions, illustrations, and biological information are presented for green kyllinga (Kyllinga brevifolia Rottb.), false green kyllinga (Kylli...

  10. Global perspective of herbicide-resistant weeds.

    PubMed

    Heap, Ian

    2014-09-01

    Two hundred and twenty weed species have evolved resistance to one or more herbicides, and there are now 404 unique cases (species × site of action) of herbicide-resistant weeds globally. ALS inhibitor-resistant weeds account for about a third of all cases (133/404) and are particularly troublesome in rice and cereals. Although 71 weed species have been identified with triazine resistance, their importance has dwindled with the shift towards Roundup Ready® crops in the USA and the reduction of triazine usage in Europe. Forty-three grasses have evolved resistance to ACCase inhibitors, with the most serious cases being Avena spp., Lolium spp., Phalaris spp., Setaria spp. and Alopecurus myosuroides, infesting more than 25 million hectares of cereal production globally. Of the 24 weed species with glyphosate resistance, 16 have been found in Roundup Ready® cropping systems. Although Conyza canadensis is the most widespread glyphosate-resistant weed, Amaranthus palmeri and Amaranthus tuberculartus are the two most economically important glyphosate-resistant weeds because of the area they infest and the fact that these species have evolved resistance to numerous other herbicide sites of action, leaving growers with few herbicidal options for their control. The agricultural chemical industry has not brought any new herbicides with novel sites of action to market in over 30 years, making growers reliant on using existing herbicides in new ways. In addition, tougher registration and environmental regulations on herbicides have resulted in a loss of some herbicides, particularly in Europe. The lack of novel herbicide chemistries being brought to market combined with the rapid increase in multiple resistance in weeds threatens crop production worldwide. PMID:24302673

  11. Favorable fragmentation: river reservoirs can impede downstream expansion of riparian weeds.

    PubMed

    Rood, Stewart B; Braatne, Jeffrey H; Goater, Lori A

    2010-09-01

    River valleys represent biologically rich corridors characterized by natural disturbances that create moist and barren sites suitable for colonization by native riparian plants, and also by weeds. Dams and reservoirs interrupt the longitudinal corridors and we hypothesized that this could restrict downstream weed expansion. To consider this "reservoir impediment" hypothesis we assessed the occurrences and abundances of weeds along a 315-km river valley corridor that commenced with an unimpounded reach of the Snake River and extended through Brownlee, Oxbow, and Hells Canyon reservoirs and dams, and downstream along the Snake River. Sampling along 206 belt transects with 3610 quadrats revealed 16 noxious and four invasive weed species. Ten weeds were upland plants, with Canada thistle (Cirsium arvense) restricted to the upstream reaches, where field morning glory (Convolvulus arvensis) was also more common. In contrast, St. John's wort (Hypericum perforatum) was more abundant below the dams, and medusahead wildrye (Taeniatherum caput-medusae) occurred primarily along the reservoirs. All seven riparian species were abundant in the upstream zones but sparse or absent below the dams. This pattern was observed for the facultative riparian species, poison hemlock (Conium maculatum) and perennial pepperweed (Lepidium latifolium), the obligate riparian, yellow nut sedge (Cyperus esculentus), the invasive perennial, reed canary grass (Phalaris arundinacea), and three invasive riparian trees, Russian olive (Elaeagnus angustifolia), false indigo (Amorpha fruticosa), and tamarisk (Tamarix spp.). The hydrophyte purple loosestrife (Lythrum salicaria) was also restricted to the upstream zone. These longitudinal patterns indicate that the reservoirs have impeded the downstream expansion of riparian weeds, and this may especially result from the repetitive draw-down and refilling of Brownlee Reservoir that imposes a lethal combination of drought and flood stress. The dams and

  12. Combining a weed traits database with a population dynamics model predicts shifts in weed communities

    PubMed Central

    Storkey, J; Holst, N; Bøjer, O Q; Bigongiali, F; Bocci, G; Colbach, N; Dorner, Z; Riemens, M M; Sartorato, I; Sønderskov, M; Verschwele, A

    2015-01-01

    A functional approach to predicting shifts in weed floras in response to management or environmental change requires the combination of data on weed traits with analytical frameworks that capture the filtering effect of selection pressures on traits. A weed traits database (WTDB) was designed, populated and analysed, initially using data for 19 common European weeds, to begin to consolidate trait data in a single repository. The initial choice of traits was driven by the requirements of empirical models of weed population dynamics to identify correlations between traits and model parameters. These relationships were used to build a generic model, operating at the level of functional traits, to simulate the impact of increasing herbicide and fertiliser use on virtual weeds along gradients of seed weight and maximum height. The model generated ‘fitness contours’ (defined as population growth rates) within this trait space in different scenarios, onto which two sets of weed species, defined as common or declining in the UK, were mapped. The effect of increasing inputs on the weed flora was successfully simulated; 77% of common species were predicted to have stable or increasing populations under high fertiliser and herbicide use, in contrast with only 29% of the species that have declined. Future development of the WTDB will aim to increase the number of species covered, incorporate a wider range of traits and analyse intraspecific variability under contrasting management and environments. PMID:26190870

  13. Weed escapes and delayed weed emergence in glyphosate-resistant soybean

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During 2001 and 2002, field experiments were conducted in soybean crops at four Minnesota locations with the aim of studying the effects of different glyphosate treatments (one-pass glyphosate, two-pass glyphosate) on weed control and weed community composition by focusing on the identity and abunda...

  14. SHIFTS IN VINEYARD WEED SEED BANK COMPOSITION IN REPONSE TO ORGANIC AND CONVENTIONAL WEED CONTROL PRACTICES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The aim of this research was to compare the organic weed control practice, soil cultivation, to the conventional practice, applications of the herbicide, glyphosate, in terms of their effects on weed seed bank in a vineyard system. The experiment was conducted in a commercial winegrape vineyard in t...

  15. Plant Pathogens at Work: Progress and Possibilities for Weed Biocontrol Part 2. Improving Weed Control Efficacy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The development of plant pathogenic weed biological control agents can be approached using two strategies, termed the classical and biological approaches. The classical involves the search for pathogens in the native range of an invasive weed and its importation and release into the area of introdu...

  16. Phytotoxicity of the volatile monoterpene citronellal against some weeds.

    PubMed

    Singh, Harminder Pal; Batish, Daizy R; Kaur, Shalinder; Kohli, Ravinder K; Arora, Komal

    2006-01-01

    A study was undertaken to assess the phytotoxicity of citronellal, an oxygenated monoterpenoid with an aldehyde group, towards some weedy species [Ageratum conyzoides L., Chenopodium album L., Parthenium hysterophorus L., Malvastrum coromandelianum (L.), Garcke, Cassia occidentalis L. and Phalaris minor Retz.]. A significant effect on weed emergence and early seedling growth was observed in a dose-response based laboratory bioassay in a sand culture. Emergence of all test weeds was completely inhibited at 100 micro/g sand content of citronellal. Seeds of A. conyzoides and P. hysterophorus failed to emerge even at 50 microg/g content. Root length was inhibited more compared to shoot length. The failure of root growth was attributed to the effect of citronellal on the mitotic activity of growing root tips cells as ascertained by the onion root tip bioassay. At 2.5 mM treatment of citronellal, mitosis was completely suppressed and at higher concentrations cells showed various degrees of distortion and were even enucleated. The post-emergent application of citronellal also caused visible injury in the form of chlorosis and necrosis, leading to wilting and even death of test weeds. Among the test weeds, the effect was severe on C. album and P. hysterophorus. There was loss of chlorophyll pigment and reduction in cellular respiration upon citronellal treatment indicating the impairment of photosynthetic and respiratory metabolism. Scanning electron microscopic studies in C. occidentalis leaves upon treatment of citronellal revealed disruption of cuticular wax, clogging of stomata and shrinkage of epidermal cells at many places. There was a rapid electrolyte leakage in the leaf tissue upon exposure to citronellal during the initial few hours. In P. minor electrolyte leakage in response to 2 mM citronellal was closer to the maximum leakage that was obtained upon boiling the tissue. The rapid ion leakage is indicative of the severe effect of citronellal on the membrane

  17. Weed control in rose-scented geranium (Pelargonium spp).

    PubMed

    Kothari, Sushil K; Singh, Chandra P; Singh, Kamla

    2002-12-01

    Abstract: Field investigations were carried out during 1999 and 2000 to identify effective chemical/ cultural methods of weed control in rose-scented geranium (Pelargonium spp). The treatments comprised pre-emergence applications of oxyfluorfen (0.15, 0.20 and 0.25 kg AI ha(-1)) and pendimethalin (0.50, 0.75 and 1.00kg AI ha(-1)), successive hand weeding, hoeing and mulching using spent of lemon grass (at 5 tonnes ha(-1)) 45 days after planting (DAP), three hand-weedings 30, 60 and 90 DAP, weed-free (frequent manual weeding) and weedy control. Broad-leaf weeds were more predominant than grass and sedge weeds, accounting for 85.8% weed density and 93.0% weed dry weight in 1999 and 77.2% weed density and 93.9% weed dry weight in 2000. Unrestricted weed growth significantly reduced geranium oil yield, by 61.6% and 70.6% in 1999 and 2000, respectively. Pre-emergence application of pendimethalin (0.75-1.00 kgAI ha(-1)) or oxyfluorfen (0.25 kg AI ha(-1)), successive hand-weeding, hoeing and mulching and three hand-weedings were highly effective in reducing weed density and dry weight and gave oil yield comparable to the weed-free check. Application of oxyfluorfen (0.15 or 0.20 kg AI ha(-1)) and pendimethalin (0.50 kg AI ha(-1)) were less effective in controlling the weed species in geranium. None of the herbicides impaired the quality of rose-scented geranium oil measured in terms of citronellol and geraniol content. PMID:12477000

  18. STRATEGIES FOR DEVELOPING BIOHERBICIDES FOR SUSTAINABLE WEED MANAGEMENT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biological weed control is an important component in sustainable crop production systems. Environmental and social pressures that shift the dependency on chemical herbicides towards integrated weed management strategies have provided opportunities for use of bioherbicides. A pragmatic approach in ...

  19. Sequential applications of pelargonic acid for weed control in squash

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed control can be a constant challenge, especially when dealing with the limited herbicide options available to organic vegetable producers. Organic squash (Cucurbita pepo L.) producers need appropriate herbicides that can effectively provide weed control throughout the production season. Although...

  20. Weed control options for organically grown vine crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic melon production requires effective weed management practices for achieving acceptable crop yield and quality. Research conducted in 2010 in southeastern Oklahoma (Lane, OK) compared several possible weed management strategies for cantaloupe. Treatments included black plastic mulch, black wo...

  1. Estimation of dose-response models for discrete and continuous data in weed science

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dose-response analysis is widely used in biological sciences and has application to a variety of risk assessment, bioassay, and calibration problems. In weed science, dose-response methodologies have typically relied on least squares estimation under an assumption of normality. Advances in computati...

  2. Guidelines for management of noxious weeds at Hanford

    SciTech Connect

    Roos, R.C.; Malady, M.B.

    1995-10-27

    Integrated Pest Management Services is responsible for management and control of noxious weeds on the Hanford Site. Weed species and populations are prioritized and objective defined, according to potential site and regional impact. Population controls are implemented according to priority. An integrated approach is planned for noxious weed control in which several management options are considered and implemented separately or in coordination to best meet management objectives. Noxious weeds are inventories and monitored to provide information for planning and program review.

  3. Weed Community Response to No-Till in North America

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Scientists and producers in Ukraine are interested in no-till crop production, but are concerned about weed management. In North America, producers have used no-till systems for several decades without increasing weed community density in croplands. Initially, weed density escalated with no-till, ...

  4. Weed control through seedling abrasion with an organic fertilizer

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many tools exist to control weeds in organic crops, and each has utility in specific situations. Nevertheless, surveys of organic farmers indicate that weed management often is second only to labor supply as their main bottleneck for success. Consequently, new tactics for managing weeds are desirabl...

  5. Weed management research in alfalfa seed production in Washington state

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed control is an important component of producing high quality and high yielding alfalfa seed. Alfalfa seed is produced with wider row and lower plant populations than alfalfa forage requiring greater weed management inputs. Flumioxazin was evaluated for weed control in alfalfa seed and forage pro...

  6. Allelopathic weed suppression through the use of cover crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ensuring sufficient food and fiber production for future generations can be hampered by limited options for weed control, particularly in developing countries where yields are reduced by up to 25% by weed species. Identifying and detailing sustainable weed control measures that can be implemented t...

  7. WEEDS AS HOSTS FOR THE SOUTHERN ROOT-KNOT NEMATODE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The southern root-knot nematode, Meloidogyne incognita, can reproduce on many different plants, including many weeds, but the amount of reproduction that occurs on weeds is not well documented. This study was conducted to document the relative host status of weeds common in Georgia. Seeds of cotton,...

  8. Agricultural weed research: a critique and two proposals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two broad aims drive weed science research: improved management and improved understanding of weed biology and ecology. In recent years, agricultural weed research addressing these two aims has effectively split into separate sub-disciplines despite repeated calls for greater integration. While some...

  9. Onion and weed response to mustard (Sinapis alba) seed meal

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed control in organic onion production is often difficult and expensive, requiring numerous cultivations and extensive hand-weeding. Onion safety and weed control with mustard seed meal (MSM) derived from Sinapis alba was evaluated in greenhouse and field trials. MSM applied at 110, 220, and 440 g...

  10. 7 CFR 361.6 - Noxious weed seeds.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 5 2014-01-01 2014-01-01 false Noxious weed seeds. 361.6 Section 361.6 Agriculture..., DEPARTMENT OF AGRICULTURE IMPORTATION OF SEED AND SCREENINGS UNDER THE FEDERAL SEED ACT § 361.6 Noxious weed... considered noxious weed seeds. (1) Seeds with no tolerances applicable to their introduction: Acacia...

  11. 7 CFR 361.6 - Noxious weed seeds.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 5 2010-01-01 2010-01-01 false Noxious weed seeds. 361.6 Section 361.6 Agriculture..., DEPARTMENT OF AGRICULTURE IMPORTATION OF SEED AND SCREENINGS UNDER THE FEDERAL SEED ACT § 361.6 Noxious weed... considered noxious weed seeds. (1) Seeds with no tolerances applicable to their introduction: Aeginetia...

  12. 7 CFR 361.6 - Noxious weed seeds.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 5 2012-01-01 2012-01-01 false Noxious weed seeds. 361.6 Section 361.6 Agriculture..., DEPARTMENT OF AGRICULTURE IMPORTATION OF SEED AND SCREENINGS UNDER THE FEDERAL SEED ACT § 361.6 Noxious weed... considered noxious weed seeds. (1) Seeds with no tolerances applicable to their introduction: Acacia...

  13. 7 CFR 361.6 - Noxious weed seeds.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 5 2013-01-01 2013-01-01 false Noxious weed seeds. 361.6 Section 361.6 Agriculture..., DEPARTMENT OF AGRICULTURE IMPORTATION OF SEED AND SCREENINGS UNDER THE FEDERAL SEED ACT § 361.6 Noxious weed... considered noxious weed seeds. (1) Seeds with no tolerances applicable to their introduction: Acacia...

  14. 7 CFR 361.6 - Noxious weed seeds.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 5 2011-01-01 2011-01-01 false Noxious weed seeds. 361.6 Section 361.6 Agriculture..., DEPARTMENT OF AGRICULTURE IMPORTATION OF SEED AND SCREENINGS UNDER THE FEDERAL SEED ACT § 361.6 Noxious weed... considered noxious weed seeds. (1) Seeds with no tolerances applicable to their introduction: Acacia...

  15. PROGRESS REPORT: WEED MANAGEMENT IN ORGANIC PEANUT PRODUCTION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Studies have been conducted in Tifton, GA since 2003 to develop weed management systems for organic peanut production. Trials in conventional tillage production systems evaluated row patterns, cultivation, and remedial weed management using propane flaming, clove oil, and citric acid. Weed control...

  16. Pest Control in Corn and Soybeans: Weeds - Insects - Diseases.

    ERIC Educational Resources Information Center

    Doersch, R. E.; And Others

    This document gives the characteristics and application rates for herbicides used to control annual weeds in corn, annual and perennial broadleaf weeds in corn, quackgrass and yellow nutsedge in corn, and annual weeds in soybeans. It also gives insecticide use information for corn and soybeans. A brief discussion of disease control in corn and…

  17. Linking theory and practice in ecological weed management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Simulation models of management effects on weed demography and the experience of successful organic and low-external-input farmers point in the same direction: long-term weed management success depends on diversified strategies that attack multiple weed life stages. In an era of declining research b...

  18. Weighing Abiotic and Biotic Influences on Weed Seed Predation Rates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed seed predation is an important ecosystem service supporting weed management in low-external-input agroecosystems. Current knowledge of weed seed predation focuses on biotic mechanisms, with less understood about the relative impact of abiotic variables. In order to quantify relative contributio...

  19. Weighing Abiotic and Biotic Influences on Weed Seed Predation Rates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed seed predation is an important ecosystem service supporting weed management in low-external-input agroecosystems. Current knowledge of weed seed predation in arable systems focuses on biotic mechanisms, with less understood about the relative impact of abiotic variables on this process. In orde...

  20. New approaches to understanding weed seed predation in agroecosystems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Postdispersal predation of weed seeds in arable systems can be a valuable ecosystem service, with the potential to support ecological approaches to weed management by reducing inputs to the soil seed bank. Scientific understanding of factors regulating weed seed predation rates is still insufficient...

  1. 7 CFR 360.200 - Designation of noxious weeds.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 5 2011-01-01 2011-01-01 false Designation of noxious weeds. 360.200 Section 360.200 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.200 Designation of noxious weeds....

  2. Simple tools and software for precision weed mapping

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Simple Tools and Software for Precision Weed Mapping L. Wiles If you have a color digital camera and a handheld GPS unit, you can map weed problems in your fields. German researchers are perfecting technology to map weed species and density with digital cameras for precision herbicide application. ...

  3. Characterization of an EST database for the perennial weed leafy spurge: an important resource for weed biology research

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genomics programs in the weed science community have not developed as rapidly as that of other crop, horticultural, forestry, and model plant systems. Development of genomic resources for selected model weeds are expected to enhance our understanding of weed biology, just as they have in other plant...

  4. Detecting Weed Infestations in Soybean Using Remote Sensing.

    NASA Astrophysics Data System (ADS)

    Clay, S. A.; Chang, J.; Clay, D. E.; Dalsted, K.; Reese, C.

    2007-12-01

    Can weed distribution maps be developed from remote sensed reflectance data? When are the appropriate times to collect these data during the season? What wavebands can be used to distinguish weedy from weed- free areas? This research examined if and when reflectance could be used to distinguish between weed-free and weed-infested (mixed species) areas in soybean and to determine the most useful wavebands to separate crop, weed, and soil reflectance differences. Treatments in the two-year study included no vegetation (bare soil), weed-free soybean, and weed-infested soybean and, in one year, 80% corn residue cover. Reflectance was measured at several sampling times from May through September in 2001 and 2002 using a hand-held multispectral radiometer equipped with band-limited optical interference filters (460 - 1650 nm). Pixel resolution was 0.8-m. Reflectance in the visible spectral range (460 to 700 nm) generally was similar among treatments. In the near-infrared (NIR) range (>700 to 1650 nm), differences among treatments were observed from soybean growth stage V-3 (about 4 weeks after planting) until mid-July to early August depending on crop vigor and canopy closure (76 cm row spacing in 2001 and 19 cm row spacing in 2002). Reflectance rankings in the NIR range when treatments could be differentiated were consistent between years and, from lowest to highest reflectance, were soil < weed-free < weed-infested areas. Increased reflectance from weed-infested areas was most likely due to increased biomass and canopy cover. Residue masked differences between weed-free and weed- infested areas during the early stages of growth due to high reflectance from the residue and reduced weed numbers in these areas. These results suggest that NIR spectral reflectance collected prior to canopy closure can be used to distinguish weed-infested from weed-free areas.

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

    PubMed Central

    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. PMID:23872717

  6. MULCHES AND OTHER COVER MATERIALS TO REDUCE WEED GROWTH IN CONTAINER-GROWN NURSERY STOCK.

    PubMed

    Rys, F; Van Wesemael, D; Van Haecke, D; Mechant, E; Gobin, B

    2014-01-01

    Due to the recent EU-wide implementation of Integrated Pest Management (IPM), alternative methods to reduce weed growth in container-grown nursery stock are needed to cut back the use of herbicides. Covering the upper layer of the substrate is known as a potential method to prevent or reduce weed growth in plant containers. As a high variety of mulches and other cover materials are on the market, however, it is no longer clear for growers which cover material is most efficient for use in containers. Therefore, we examined the effect on weed growth of different mulches and other cover materials, including Pinus maritima, P. sylvestris, Bio-Top Basic, Bio-Top Excellent, coco chips fine, hemp fibres, straw pellets, coco disk 180LD and jute disk. Cover materials were applied immediately after repotting of Ligustrum ovalifolium or planting of Fagus sylvatica. At regular times, both weed growth and side effects (e.g., plant growth, water status of the substrate, occurrence of mushrooms, foraging of birds, complete cover of the substrate and fixation) were assessed. All examined mulches or other cover materials were able to reduce weed growth on the containers during the whole growing season. Weed suppression was even better than that of a chemical treated control. Although all materials showed some side effects, the impact on plant growth is most important to the grower and depends not only on material characteristics (e.g., biodegradation, nutrient leaching and N-immobilisation) but also on container size and climatic conditions. In conclusion, mulches and other cover materials can be a valuable tool within IPM to lower herbicide use. To enable a deliberate choice of which cover material is best used in a specific situation more research is needed on lifespan and stability as well as on economic characteristics of the materials. PMID:26084081

  7. Susceptibility of Several Common Subtropical Weeds to Meloidogyne arenaria, M. incognita, and M. javanica.

    PubMed

    Kokalis-Burelle, Nancy; Rosskopf, Erin N

    2012-06-01

    Experiments were conducted in the greenhouse to assess root galling and egg production of three root-knot nematode species, Meloidogyne arenaria, M. incognita, and M. javanica, on several weeds common to Florida agricultural land. Weeds evaluated were Amaranthus retroflexus (redroot pigweed), Cyperus esculentus (yellow nutsedge), Eleusine indica (goosegrass), Portulaca oleracea (common purslane), and Solanum americanum (American black nightshade). Additionally, although it is recommended as a cover crop in southern regions of the U.S., Aeschynomene americana (American jointvetch) was evaluated as a weed following the detection of root galling in a heavy volunteer infestation of an experimental field in southeastern Florida. Weeds were propagated from seed and inoculated with 1000 nematode eggs when plants reached the two true-leaf stage. Tomato (Solanum lycopersicum 'Rutgers') was included as a positive control. Aeschynomene americana and P. oleracea roots supported the highest number of juveniles (J2) and had the highest number of eggs/g of root for all three species of Meloidogyne tested. However, though P. oleracea supported very high root levels of the three nematode species tested, its fleshy roots did not exhibit severe gall symptoms. Low levels of apparent galling, combined with high egg production, increase the potential for P. oleracea to support populations of these three species of root-knot nematodes to a degree that may not be appropriately recognized. This research quantifies the impact of P. oleracea as a host for M. arenaria, M. incognita, and M. javanica compared to several other important weeds commonly found in Florida agricultural production, and the potential for A. americana to serve as an important weed host of the three species of root-knot nematode tested in southern regions of Florida. PMID:23482324

  8. Susceptibility of Several Common Subtropical Weeds to Meloidogyne arenaria, M. incognita, and M. javanica

    PubMed Central

    Kokalis-Burelle, Nancy; Rosskopf, Erin N.

    2012-01-01

    Experiments were conducted in the greenhouse to assess root galling and egg production of three root-knot nematode species, Meloidogyne arenaria, M. incognita, and M. javanica, on several weeds common to Florida agricultural land. Weeds evaluated were Amaranthus retroflexus (redroot pigweed), Cyperus esculentus (yellow nutsedge), Eleusine indica (goosegrass), Portulaca oleracea (common purslane), and Solanum americanum (American black nightshade). Additionally, although it is recommended as a cover crop in southern regions of the U.S., Aeschynomene americana (American jointvetch) was evaluated as a weed following the detection of root galling in a heavy volunteer infestation of an experimental field in southeastern Florida. Weeds were propagated from seed and inoculated with 1000 nematode eggs when plants reached the two true-leaf stage. Tomato (Solanum lycopersicum ‘Rutgers’) was included as a positive control. Aeschynomene americana and P. oleracea roots supported the highest number of juveniles (J2) and had the highest number of eggs/g of root for all three species of Meloidogyne tested. However, though P. oleracea supported very high root levels of the three nematode species tested, its fleshy roots did not exhibit severe gall symptoms. Low levels of apparent galling, combined with high egg production, increase the potential for P. oleracea to support populations of these three species of root-knot nematodes to a degree that may not be appropriately recognized. This research quantifies the impact of P. oleracea as a host for M. arenaria, M. incognita, and M. javanica compared to several other important weeds commonly found in Florida agricultural production, and the potential for A. americana to serve as an important weed host of the three species of root-knot nematode tested in southern regions of Florida. PMID:23482324

  9. Aminopyralid residue impacts on potatoes and weeds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aminopyralid is used in Alaska to control certain invasive weed species; however it appears to have an extended soil half-life in interior Alaska resulting in carry-over injury in potatoes. Field studies at three experiment stations in Delta Junction, Fairbanks, and Palmer, Alaska were established ...

  10. Diversifying spring wheat systems influences weed community

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed competition constrains dryland crop production in the northern Great Plains. We initiated a field trial in 2004 comparing four crop rotations, with each component in a two-by-two matrix of tillage (conventional vs. zero tillage) and management (conventional vs. ecological) systems. Rotations ...

  11. Weed Research in Alfalfa Seed Production 2007

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed control in alfalfa seed production is important to produce high quality and high yield of alfalfa seed. Herbicides were tested on a commercial field of alfalfa seed in central Washington in 2007. Flumioxzin slightly injured alfalfa when applied at 0.125 and 0.25 lb ai/a. to dormant alfalfa in M...

  12. Bio-gas production from alligator weeds

    NASA Technical Reports Server (NTRS)

    Latif, A.

    1976-01-01

    Laboratory experiments were conducted to study the effect of temperature, sample preparation, reducing agents, light intensity and pH of the media, on bio-gas and methane production from the microbial anaerobic decomposition of alligator weeds (Alternanthera philoxeroides. Efforts were also made for the isolation and characterization of the methanogenic bacteria.

  13. Alternathera philoxeroides (Martius) Grisebach - alligator weed

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biological control of Alternanthera philoxeroides, alligator weed, began when George Vogt, USDA, conducted several surveys by public transport in South America during the 1960s. Three agents were released in USA and two of them, the flea beetle Agasicles hygrophila and the moth Arcola malloi were re...

  14. Weed Science and Technology. MP-17.

    ERIC Educational Resources Information Center

    Alley, Harold P.; Lee, Gary A.

    This document is one in a series distributed by the Agricultural Extension Service of the University of Wyoming-Laramie. It presents the principles and methods of weed control especially as it relates to the use of herbicides. The factors influencing the effectiveness of both foliar-applied and soil-applied herbicides are discussed. A listing of…

  15. Natural Compounds for Pest and Weed Control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The control of insect pests and invasive weeds has become more species-selective because of activity-guided isolation, structure elucidation, and total synthesis of naturally produced substances with important biological activities. Examples of isolated compounds include insect pheromones, antifeed...

  16. Challenges in Weed Management Without Methyl Bromide

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Methyl bromide has been used for several decades for pre-plant soil fumigation in high value agricultural and horticultural crops because it can provide broad-spectrum control of insects, nematodes, pathogens, and weeds. However, MeBr has been identified as a powerful ozone-depleting chemical and i...

  17. Acetic acid and weed control in onions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed control is a major challenge in conventional and organic production systems, especially for organically produced sweet onion (Allium cepa L.). Although corn gluten meal shows great promise as an organic preemergent herbicide for onions, research has shown the need for supplemental, postemergen...

  18. Bioactive compounds for pest and weed control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The control of insect pests and invasive weeds has become more species-selective because of activity-guided isolation, structure elucidation, and total synthesis of naturally produced substances with important biological activities. Examples of isolated compounds include insect pheromones, antifeed...

  19. Organic weed control in Cowpea: Summer 2006

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cowpea is a major vegetable crop within the state of Oklahoma. It is utilized as both a processing crop by the canning industry and as a fresh market crop for farmer’s and roadside markets. Traditionally weed control in this crop is primarily handled with preemergence and some postemergence herbicid...

  20. Dynamics of Weeds in the Soil Seed Bank: A Hidden Markov Model to Estimate Life History Traits from Standing Plant Time Series

    PubMed Central

    Borgy, Benjamin; Reboud, Xavier; Peyrard, Nathalie; Sabbadin, Régis; Gaba, Sabrina

    2015-01-01

    Predicting the population dynamics of annual plants is a challenge due to their hidden seed banks in the field. However, such predictions are highly valuable for determining management strategies, specifically in agricultural landscapes. In agroecosystems, most weed seeds survive during unfavourable seasons and persist for several years in the seed bank. This causes difficulties in making accurate predictions of weed population dynamics and life history traits (LHT). Consequently, it is very difficult to identify management strategies that limit both weed populations and species diversity. In this article, we present a method of assessing weed population dynamics from both standing plant time series data and an unknown seed bank. We use a Hidden Markov Model (HMM) to obtain estimates of over 3,080 botanical records for three major LHT: seed survival in the soil, plant establishment (including post-emergence mortality), and seed production of 18 common weed species. Maximum likelihood and Bayesian approaches were complementarily used to estimate LHT values. The results showed that the LHT provided by the HMM enabled fairly accurate estimates of weed populations in different crops. There was a positive correlation between estimated germination rates and an index of the specialisation to the crop type (IndVal). The relationships between estimated LHTs and that between the estimated LHTs and the ecological characteristics of weeds provided insights into weed strategies. For example, a common strategy to cope with agricultural practices in several weeds was to produce less seeds and increase germination rates. This knowledge, especially of LHT for each type of crop, should provide valuable information for developing sustainable weed management strategies. PMID:26427023

  1. Dynamics of Weeds in the Soil Seed Bank: A Hidden Markov Model to Estimate Life History Traits from Standing Plant Time Series.

    PubMed

    Borgy, Benjamin; Reboud, Xavier; Peyrard, Nathalie; Sabbadin, Régis; Gaba, Sabrina

    2015-01-01

    Predicting the population dynamics of annual plants is a challenge due to their hidden seed banks in the field. However, such predictions are highly valuable for determining management strategies, specifically in agricultural landscapes. In agroecosystems, most weed seeds survive during unfavourable seasons and persist for several years in the seed bank. This causes difficulties in making accurate predictions of weed population dynamics and life history traits (LHT). Consequently, it is very difficult to identify management strategies that limit both weed populations and species diversity. In this article, we present a method of assessing weed population dynamics from both standing plant time series data and an unknown seed bank. We use a Hidden Markov Model (HMM) to obtain estimates of over 3,080 botanical records for three major LHT: seed survival in the soil, plant establishment (including post-emergence mortality), and seed production of 18 common weed species. Maximum likelihood and Bayesian approaches were complementarily used to estimate LHT values. The results showed that the LHT provided by the HMM enabled fairly accurate estimates of weed populations in different crops. There was a positive correlation between estimated germination rates and an index of the specialisation to the crop type (IndVal). The relationships between estimated LHTs and that between the estimated LHTs and the ecological characteristics of weeds provided insights into weed strategies. For example, a common strategy to cope with agricultural practices in several weeds was to produce less seeds and increase germination rates. This knowledge, especially of LHT for each type of crop, should provide valuable information for developing sustainable weed management strategies. PMID:26427023

  2. RNAseq reveals weed-induced PIF3-like as a candidate target to manipulate weed stress response in soybean.

    PubMed

    Horvath, David P; Hansen, Stephanie A; Moriles-Miller, Janet P; Pierik, Ronald; Yan, Changhui; Clay, David E; Scheffler, Brian; Clay, Sharon A

    2015-07-01

    Weeds reduce yield in soybeans (Glycine max) through incompletely defined mechanisms. The effects of weeds on the soybean transcriptome were evaluated in field conditions during four separate growing seasons. RNASeq data were collected from six biological samples of soybeans growing with or without weeds. Weed species and the methods to maintain weed-free controls varied between years to mitigate treatment effects, and to allow detection of general soybean weed responses. Soybean plants were not visibly nutrient- or water-stressed. We identified 55 consistently downregulated genes in weedy plots. Many of the downregulated genes were heat shock genes. Fourteen genes were consistently upregulated. Several transcription factors including a PHYTOCHROME INTERACTING FACTOR 3-like gene (PIF3) were included among the upregulated genes. Gene set enrichment analysis indicated roles for increased oxidative stress and jasmonic acid signaling responses during weed stress. The relationship of this weed-induced PIF3 gene to genes involved in shade avoidance responses in Arabidopsis provide evidence that this gene may be important in the response of soybean to weeds. These results suggest that the weed-induced PIF3 gene will be a target for manipulating weed tolerance in soybean. PMID:25711503

  3. Novel non-chemically amplified (n-CARs) negative resists for EUVL

    NASA Astrophysics Data System (ADS)

    Singh, Vikram; Satyanarayana, V. S. V.; Sharma, Satinder K.; Ghosh, Subrata; Gonsalves, Kenneth E.

    2014-03-01

    We report the lithography performance of novel non chemical amplified (n-CARS) negative photoresist materials which are accomplished by homopolymers and copolymers that are prepared from monomers containing sulfonium groups. The latter have long been found to be sensitive to UV radiation and undergo polarity change on exposure. For this reason, these groups were chosen as radiation sensitive groups in non- CARs that are discussed herein. Novel n-CAR negative resists were synthesized and characterized for EUVL applications, as they are directly sensitive to radiation without utilizing the concept of chemical amplification. The n-CARs achieved 20 and 16 nm L/2S, L/S patterns to meet the ITRS requirements. We will also discuss the sensitivity and LER of these negative n-CARS to e-beam irradiation which will provide a basis for EUVL down to the 16 nm node and below. These new negative tone resist provide a viable path forward for designing non- chemically amplified resists that can obtain higher resolutions than current chemically amplified resists at competitive sensitivities.

  4. Weed management practice selection among Midwest U.S. organic growers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic agricultural systems increase the complexity of weed management, leading organic farmers to cite weeds as the greatest barrier to organic production. Integrated Weed Management (IWM) systems have been developed to address the ecological implications of weeds and weed management in cropping s...

  5. Optical weed detection and evaluation using reflection measurements

    NASA Astrophysics Data System (ADS)

    Vrindts, Els; De Baerdemaeker, Josse

    1999-01-01

    For the site-specific application of herbicides, the automatic detection and evaluation of weeds is necessary. Since reflectance of crop, weeds and soil differs in visual and near IR wavelengths, there is a potential for using reflection measurements at different wavelengths to distinguish between them. Diffuse reflectance spectra of crop and weed leaves were used to evaluate the possibilities of weed detection with reflection measurements. Fourteen different weed species and four crops were included in the dataset. Classification of the spectra in crop, weeds and soil is possible, based on 3 to 7 narrow wavelength bands. The spectral analysis was repeated for reflectance measurements of canopies. Sugarbeet and Maize and 7 weed species were included in the measurements. The classification into crop and weeds was still possible, suing a limited number of wavelength band ratios. This suggest that reflection measurements at a limited number of wavelength bands could be used to detect and treat weeds in a field. This is a great environmental benefit, as agrochemicals will only be used where they are needed. The possibilities of using optical reflectance for weed detection and treatment in the field are discussed.

  6. Non-chemical and non-contact cell-to-cell communication: a short review

    PubMed Central

    Scholkmann, Felix; Fels, Daniel; Cifra, Michal

    2013-01-01

    Cell-to-cell communication is the basis of coordinated cellular activity and thus fundamental for the functioning of biological systems. In a recently published research article by Chaban et al. (Am. J. Transl. Res., 5(1), 69-79), the authors report on interesting new experimental findings supporting a neuro-hormonal independent, non-diffusible cell-to-cell signaling. Our paper aims to (i) discuss some critical notions used by the authors to describe their findings, and (ii) briefly review related experimental work performed so far but not discussed in the original work of Chaban et al. In our opinion, the research on principles of non-chemical and non-contact cell-to-cell communication has the potential to offer new fundamental insights into biological processes. With this paper, we want to encourage future research on this topic by discussing critical issues and giving an overview of the current state of research. PMID:24093056

  7. Non-chemical and non-contact cell-to-cell communication: a short review.

    PubMed

    Scholkmann, Felix; Fels, Daniel; Cifra, Michal

    2013-01-01

    Cell-to-cell communication is the basis of coordinated cellular activity and thus fundamental for the functioning of biological systems. In a recently published research article by Chaban et al. (Am. J. Transl. Res., 5(1), 69-79), the authors report on interesting new experimental findings supporting a neuro-hormonal independent, non-diffusible cell-to-cell signaling. Our paper aims to (i) discuss some critical notions used by the authors to describe their findings, and (ii) briefly review related experimental work performed so far but not discussed in the original work of Chaban et al. In our opinion, the research on principles of non-chemical and non-contact cell-to-cell communication has the potential to offer new fundamental insights into biological processes. With this paper, we want to encourage future research on this topic by discussing critical issues and giving an overview of the current state of research. PMID:24093056

  8. Modeling Joint Exposures and Health Outcomes for Cumulative Risk Assessment: the Case of Radon and Smoking

    EPA Science Inventory

    Community-based cumulative risk assessment requires characterization of exposures to multiple chemical and non-chemical stressors, with consideration of how the non-chemical stressors may influence risks from chemical stressors. Residential radon provides an interesting case exam...

  9. Can Arbuscular Mycorrhizal Fungi Reduce the Growth of Agricultural Weeds?

    PubMed Central

    Veiga, Rita S. L.; Jansa, Jan; Frossard, Emmanuel; van der Heijden, Marcel G. A.

    2011-01-01

    Background Arbuscular mycorrhizal fungi (AMF) are known for their beneficial effects on plants. However, there is increasing evidence that some ruderal plants, including several agricultural weeds, respond negatively to AMF colonization. Here, we investigated the effect of AMF on the growth of individual weed species and on weed-crop interactions. Methodology/Principal Findings First, under controlled glasshouse conditions, we screened growth responses of nine weed species and three crops to a widespread AMF, Glomus intraradices. None of the weeds screened showed a significant positive mycorrhizal growth response and four weed species were significantly reduced by the AMF (growth responses between −22 and −35%). In a subsequent experiment, we selected three of the negatively responding weed species – Echinochloa crus-galli, Setaria viridis and Solanum nigrum – and analyzed their responses to a combination of three AMF (Glomus intraradices, Glomus mosseae and Glomus claroideum). Finally, we tested whether the presence of a crop (maize) enhanced the suppressive effect of AMF on weeds. We found that the growth of the three selected weed species was also reduced by a combination of AMF and that the presence of maize amplified the negative effect of AMF on the growth of E. crus-galli. Conclusions/Significance Our results show that AMF can negatively influence the growth of some weed species indicating that AMF have the potential to act as determinants of weed community structure. Furthermore, mycorrhizal weed growth reductions can be amplified in the presence of a crop. Previous studies have shown that AMF provide a number of beneficial ecosystem services. Taken together with our current results, the maintenance and promotion of AMF activity may thereby contribute to sustainable management of agroecosystems. However, in order to further the practical and ecological relevance of our findings, additional experiments should be performed under field conditions. PMID

  10. Relative influence of chemical and non-chemical stressors on invertebrate communities: a case study in the Danube River.

    PubMed

    Rico, Andreu; Van den Brink, Paul J; Leitner, Patrick; Graf, Wolfram; Focks, Andreas

    2016-11-15

    A key challenge for the ecological risk assessment of chemicals has been to evaluate the relative contribution of chemical pollution to the variability observed in biological communities, as well as to identify multiple stressor groups. In this study we evaluated the toxic pressure exerted by >200 contaminants to benthic macroinvertebrates in the Danube River using the Toxic Unit approach. Furthermore, we evaluated correlations between several stressors (chemical and non-chemical) and biological indices commonly used for the ecological status assessment of aquatic ecosystems. We also performed several variation partitioning analyses to evaluate the relative contribution of contaminants and other abiotic parameters (i.e. habitat characteristics, hydromorphological alterations, water quality parameters) to the structural and biological trait variation of the invertebrate community. The results of this study show that most biological indices significantly correlate to parameters related to habitat and physico-chemical conditions, but showed limited correlation with the calculated toxic pressure. The calculated toxic pressure, however, showed little variation between sampling sites, which complicates the identification of pollution-induced effects. The results of this study show that the variation in the structure and trait composition of the invertebrate community are mainly explained by habitat and water quality parameters, whereas hydromorphological alterations play a less important role. Among the water quality parameters, physico-chemical parameters such as suspended solids, nutrients or dissolved oxygen explained a larger part of the variation in the invertebrate community as compared to metals or organic contaminants. Significant correlations exist between some physico-chemical measurements (e.g. nutrients) and some chemical classes (i.e. pharmaceuticals, chemicals related to human presence) which constitute important multiple stressor groups. This study

  11. Critical period of weed control in aerobic rice.

    PubMed

    Anwar, M P; Juraimi, A S; Samedani, B; Puteh, A; Man, A

    2012-01-01

    Critical period of weed control is the foundation of integrated weed management and, hence, can be considered the first step to design weed control strategy. To determine critical period of weed control of aerobic rice, field trials were conducted during 2010/2011 at Universiti Putra Malaysia. A quantitative series of treatments comprising two components, (a) increasing duration of weed interference and (b) increasing length of weed-free period, were imposed. Critical period was determined through Logistic and Gompertz equations. Critical period varied between seasons; in main season, it started earlier and lasted longer, as compared to off-season. The onset of the critical period was found relatively stable between seasons, while the end was more variable. Critical period was determined as 7-49 days after seeding in off-season and 7-53 days in main season to achieve 95% of weed-free yield, and 23-40 days in off-season and 21-43 days in main season to achieve 90% of weed-free yield. Since 5% yield loss level is not practical from economic view point, a 10% yield loss may be considered excellent from economic view point. Therefore, aerobic rice should be kept weed-free during 21-43 days for better yield and higher economic return. PMID:22778701

  12. Activity of mesotrione on resistant weeds in maize.

    PubMed

    Sutton, Peter; Richards, Claire; Buren, Larry; Glasgow, Les

    2002-09-01

    Mesotrione is a new callistemone herbicide that inhibits the HPPD enzyme (p-hydroxyphenylpyruvate dioxygenase) and introduces a new naturally selective tool into weed-management programmes for use in maize. Mesotrione provides control of the major broad-leaved weeds, and it can be used in integrated weed-management programmes depending on the grower's preferred weed-control strategy. At post-emergence rates of 150 g AI ha-1 or less, mesotrione provides naturally selective control of key species that may show triazine resistance (TR), e.g. Chenopodium album L, Amaranthus species, Solanum nigrum L, as well as species of weed that show resistance to acetolactase synthase (ALS) inhibitors e.g. Xanthium strumarium L, Amaranthus spp and Sonchus spp. The data presented show that resistant and susceptible biotypes of these species with resistance to triazine herbicides, such as atrazine, simazine, terbutylazine and metribuzin, or ALS-inhibitor herbicides, such as imazethepyr, remain susceptible to mesotrione. These results confirm that there is no cross-resistance in biotypes with target site resistance to triazine or ALS-inhibiting herbicides. It is important that herbicide choice and rotation becomes an integral part of planning weed management, so as to minimise the risks of crop losses from weed competition, build-up of weed seed in the soil and the further development of weed resistance across a range of herbicide modes of action. PMID:12233193

  13. Herbicide-resistant weed management: focus on glyphosate.

    PubMed

    Beckie, Hugh J

    2011-09-01

    This review focuses on proactive and reactive management of glyphosate-resistant (GR) weeds. Glyphosate resistance in weeds has evolved under recurrent glyphosate usage, with little or no diversity in weed management practices. The main herbicide strategy for proactively or reactively managing GR weeds is to supplement glyphosate with herbicides of alternative modes of action and with soil-residual activity. These herbicides can be applied in sequences or mixtures. Proactive or reactive GR weed management can be aided by crop cultivars with alternative single or stacked herbicide-resistance traits, which will become increasingly available to growers in the future. Many growers with GR weeds continue to use glyphosate because of its economical broad-spectrum weed control. Government farm policies, pesticide regulatory policies and industry actions should encourage growers to adopt a more proactive approach to GR weed management by providing the best information and training on management practices, information on the benefits of proactive management and voluntary incentives, as appropriate. Results from recent surveys in the United States indicate that such a change in grower attitudes may be occurring because of enhanced awareness of the benefits of proactive management and the relative cost of the reactive management of GR weeds. PMID:21548004

  14. Impact of Parthenium weeds on earthworms (Eudrilus eugeniae) during vermicomposting.

    PubMed

    Rajiv, P; Rajeshwari, Sivaraj; Rajendran, Venckatesh

    2014-11-01

    The aim of this work is to evaluate the effect of Parthenium-mediated compost on Eudrilus eugeniae during the process of vermicomposting. Nine different concentrations of Parthenium hysterophorus and cow dung mixtures were used to assess toxicity. The earthworms' growth, fecundity and antioxidant enzyme levels were analysed every 15 days. The antioxidant activities of enzymes [superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx)], considered as biomarkers, indicate the biochemical and oxidative stresses due to the toxin from Parthenium weeds. The earthworms' growth, biomass gain, cocoon production and antioxidant enzymes were in a low level in a high concentration of P. hysterophorus (without cow dung). The results clearly indicated that appropriate mixing of P. hysterophorus quantity is an essential factor for the survival of earthworms without causing any harm. PMID:24938809

  15. Are Weeds Hitchhiking a Ride on Your Car? A Systematic Review of Seed Dispersal on Cars

    PubMed Central

    Ansong, Michael; Pickering, Catherine

    2013-01-01

    When traveling in cars, we can unintentionally carry and disperse weed seed; but which species, and where are they a problem? To answer these questions, we systematically searched the scientific literature to identify all original research studies that assess seed transported by cars and listed the species with seed on/in cars. From the 13 studies that fit these criteria, we found 626 species from 75 families that have seed that can be dispersed by cars. Of these, 599 are listed as weeds in some part of the world, with 439 listed as invasive or naturalized alien species in one or more European countries, 248 are invasive/noxious weeds in North America, 370 are naturalized alien species in Australia, 167 are alien species in India, 77 are invasive species in China and 23 are declared weeds/invaders in South Africa. One hundred and one are classified as internationally important environmental weeds. Although most (487) were only recorded once, some species such as Chenopodium album, Poa pratensis and Trifolium repens were common among studies. Perennial graminoids seem to be favoured over annual graminoids while annual forbs are favoured over perennial forbs. Species characteristics including seed size and morphology and where the plants grew affected the probability that their seed was transported by cars. Seeds can be found in many different places on cars including under the chassis, front and rear bumpers, wheel wells and rims, front and back mudguards, wheel arches, tyres and on interior floor mats. With increasing numbers of cars and expanding road networks in many regions, these results highlight the importance of cars as a dispersal mechanism, and how it may favour invasions by some species over others. Strategies to reduce the risk of seed dispersal by cars include reducing seed on cars by mowing road verges and cleaning cars. PMID:24265803

  16. Are weeds hitchhiking a ride on your car? A systematic review of seed dispersal on cars.

    PubMed

    Ansong, Michael; Pickering, Catherine

    2013-01-01

    When traveling in cars, we can unintentionally carry and disperse weed seed; but which species, and where are they a problem? To answer these questions, we systematically searched the scientific literature to identify all original research studies that assess seed transported by cars and listed the species with seed on/in cars. From the 13 studies that fit these criteria, we found 626 species from 75 families that have seed that can be dispersed by cars. Of these, 599 are listed as weeds in some part of the world, with 439 listed as invasive or naturalized alien species in one or more European countries, 248 are invasive/noxious weeds in North America, 370 are naturalized alien species in Australia, 167 are alien species in India, 77 are invasive species in China and 23 are declared weeds/invaders in South Africa. One hundred and one are classified as internationally important environmental weeds. Although most (487) were only recorded once, some species such as Chenopodium album, Poa pratensis and Trifolium repens were common among studies. Perennial graminoids seem to be favoured over annual graminoids while annual forbs are favoured over perennial forbs. Species characteristics including seed size and morphology and where the plants grew affected the probability that their seed was transported by cars. Seeds can be found in many different places on cars including under the chassis, front and rear bumpers, wheel wells and rims, front and back mudguards, wheel arches, tyres and on interior floor mats. With increasing numbers of cars and expanding road networks in many regions, these results highlight the importance of cars as a dispersal mechanism, and how it may favour invasions by some species over others. Strategies to reduce the risk of seed dispersal by cars include reducing seed on cars by mowing road verges and cleaning cars. PMID:24265803

  17. Weed-cover versus weed-removal management in olive orchards: influence on the carbon balance at the ecosystem scale

    NASA Astrophysics Data System (ADS)

    Chamizo, Sonia; Serrano-Ortiz, Penélope; Vicente-Vicente, José Luis; Sánchez-Cañete, Enrique P.; López-Ballesteros, Ana; Kowalski, Andrew S.

    2016-04-01

    Agriculture plays an important role in the C budget at the global scale. Traditional practices based on soil tillage and applying herbicides to remove weeds have caused damage to soils and led to important losses of soil organic C and increased CO2 emissions to the atmosphere. Changing trends from traditional agriculture to conservation agriculture practices may have an important role in both C and water budgets and the transformation of agriculture from C source to C sink. The objective of this study was to analyse the effect of two treatments, weed removal by herbicides versus weed cover conservation, on the C balance in an irrigated olive orchard in SE Spain. Measurements of CO2 exchange were made from October 2014 to September 2015 using two eddy covariance towers, one for each olive crop treatment. Results show that CO2 fluxes at the ecosystem scale were similar in the two treatments during initial conditions, prior to weed growth in the soils without herbicide application (October). During the first week, daily net ecosystem exchange (NEE) was close to zero in both treatments, with values ranging from 1.06 to -0.41 g C m-2 in the weed cover treatment, and from 0.76 to -0.69 g C m-2 in the weed removal treatment. As weed growth increased, higher net CO2 assimilation was found in the treatment with weed cover. In both treatments, maximum net CO2 assimilation was found in March, with a monthly NEE of -72 and -28 g C m-2 in the treatment with and without weed cover, respectively. In May, after the weeds were cut and left on the soil, a strong increase was observed in NEE in the treatment with weed cover due to decreased CO2 assimilation and increased respiration compared to the treatment without weed cover. Therefore, soil chamber measurements showed average respiration rates of 2.57 and 1.57 μmol m-2 s-2 in the weed cover and weed removal treatment, respectively. Finally, the highest monthly NEE was registered during July, with both treatments showing a similar

  18. Bringing science to medicine: an interview with Larry Weed, inventor of the problem-oriented medical record

    PubMed Central

    Wright, Adam; Sittig, Dean F; McGowan, Julie; Ash, Joan S; Weed, Lawrence L

    2014-01-01

    Larry Weed, MD is widely known as the father of the problem-oriented medical record and inventor of the now-ubiquitous SOAP (subjective/objective/assessment/plan) note, for developing an electronic health record system (Problem-Oriented Medical Information System, PROMIS), and for founding a company (since acquired), which developed problem-knowledge couplers. However, Dr Weed's vision for medicine goes far beyond software—over the course of his storied career, he has relentlessly sought to bring the scientific method to medical practice and, where necessary, to point out shortcomings in the system and advocate for change. In this oral history, Dr Weed describes, in his own words, the arcs of his long career and the work that remains to be done. PMID:24872343

  19. Bringing science to medicine: an interview with Larry Weed, inventor of the problem-oriented medical record.

    PubMed

    Wright, Adam; Sittig, Dean F; McGowan, Julie; Ash, Joan S; Weed, Lawrence L

    2014-01-01

    Larry Weed, MD is widely known as the father of the problem-oriented medical record and inventor of the now-ubiquitous SOAP (subjective/objective/assessment/plan) note, for developing an electronic health record system (Problem-Oriented Medical Information System, PROMIS), and for founding a company (since acquired), which developed problem-knowledge couplers. However, Dr Weed's vision for medicine goes far beyond software--over the course of his storied career, he has relentlessly sought to bring the scientific method to medical practice and, where necessary, to point out shortcomings in the system and advocate for change. In this oral history, Dr Weed describes, in his own words, the arcs of his long career and the work that remains to be done. PMID:24872343

  20. Changes in dicot-weeds species composition in spring barley in Latvia during the past 20 years.

    PubMed

    Vanaga, I

    2012-01-01

    Dicot weed populations were assessed in spring barley trials carried out in four three-years periods at 5-year intervals: 1990-1992, 1995-1997; 2001-2003 and 2006-2008. The overall aim of this research was to evaluate the changes in dicot-weed infestations in spring barley in fields of one region (Riga) of Latvia in sod-podzolic loamy sand soil. The results of the trials showed that Galeopsis spp, Stellaoria media, Viola orvensis and Chenopodium album were among the most frequent weed species in the periods of 1990-1992 and 1995-1997. The occurrence of C. album and V. arvensis increased during the periods of 2001-2003 and 2006-2008. PMID:23878992

  1. Weed management practices for organic production of trailing blackberry. II. Accumulation and loss of plant biomass and nutrients

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A study was conducted to assess the impact of cultivar and weed management on accumulation and loss of plant biomass and nutrients during the first 3 years of establishment when using organic fertilizer in trailing blackberry. Treatments included two cultivars, Marion and Black Diamond, each with ei...

  2. 13Carbon isotope discrimination in major C4 weeds of rice-implications for root interference studies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Assessing below ground plant interference in rice has been difficult in the past because separation of intertwined weed and crop roots is nearly impossible. A simple 13C depletion method was previously developed for simultaneous quantification of barnyardgrass and rice roots in flooded fields. Thi...

  3. Occurrence and trends of weed seed and ergot contaminants in Oregon grown Poa pratensis and Poa trivialis seed lots

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study was conducted to assess the diversity and frequency of occurrence of weed seeds and sclerotia of the fungus Claviceps purpurea (ergot) in certified seed lots of P. pratensis (Kentucky bluegrass) and P. trivialis (rough bluegrass) based on purity analysis at the Oregon State University See...

  4. Herbicide Resistant Weeds: Do Economic Thresholds Still Have a Role in Weed Management?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Concern over the development of herbicide resistant weeds has prompted a closer look at the validity of using economic thresholds (ET) as a basis for making treatment decisions. In situations where herbicide resistance is suspected, growers are often advised to employ control measures to completely ...

  5. SURVEY OF WEEDS AND WEED MANAGEMENT IN SWEET CORN GROWN FOR PROCESSING

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The north-central United States produces approximately one-half of sweet corn grown for processing, predominantly in Illinois, Minnesota, and Wisconsin. Improved weed management systems for sweet corn are desired greatly by growers, processors, and the seed industry; however, information on problem...

  6. Non-surgical and non-chemical attempts to treat echinococcosis: do they work?

    PubMed Central

    Tamarozzi, Francesca; Vuitton, Lucine; Brunetti, Enrico; Vuitton, Dominique Angèle; Koch, Stéphane

    2014-01-01

    Cystic echinococcosis (CE) and alveolar echinococcosis (AE) are chronic, complex and neglected diseases. Their treatment depends on a number of factors related to the lesion, setting and patient. We performed a literature review of curative or palliative non-surgical, non-chemical interventions in CE and AE. In CE, some of these techniques, like radiofrequency thermal ablation (RFA), were shelved after initial attempts, while others, such as High-Intensity Focused Ultrasound, appear promising but are still in a pre-clinical phase. In AE, RFA has never been tested, however, radiotherapy or heavy-ion therapies have been attempted in experimental models. Still, application to humans is questionable. In CE, although prospective clinical studies are still lacking, therapeutic, non-surgical drainage techniques, such as PAIR (puncture, aspiration, injection, re-aspiration) and its derivatives, are now considered a useful option in selected cases. Finally, palliative, non-surgical drainage techniques such as US- or CT-guided percutaneous biliary drainage, centro-parasitic abscesses drainage, or vascular stenting were performed successfully. Recently, endoscopic retrograde cholangiopancreatography (ERCP)-associated techniques have become increasingly used to manage biliary fistulas in CE and biliary obstructions in AE. Development of pre-clinical animal models would allow testing for AE techniques developed for other indications, e.g. cancer. Prospective trials are required to determine the best use of PAIR, and associated procedures, and the indications and techniques of palliative drainage. PMID:25531730

  7. Weed Seedling Emergence and Survival as Affected by Crop Canopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study measured impact of cool-season crops on seedling emergence, survival, and seed production of weeds common in corn and soybean. Weed dynamics were monitored in permanently-marked quadrats in winter wheat, spring wheat, and canola. Three species, green foxtail, yellow foxtail, and common ...

  8. Third season weed control in blackberries using synthetic ground covers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Synthetic weed barriers, which have shown promise in a first fruiting season ‘Kiowa’ blackberry (Rubus spp) planting (near Monte Alto, TX; Lat. 26º 26’N), were evaluated for a second fruiting season in 2008. Weed removal times were significantly shorter and material integrity unaffected by time (Ma...

  9. Corn gluten meal for weed control in cowpea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cowpea, a major crop in Oklahoma, is produced for the fresh market and canning industry. Synthetic preemergence and postemergence herbicides are the primary weed control method in conventional (non-organic) production systems. Organic weed control in organic cowpea production includes obstacles wh...

  10. Weed resistance challenges and management under herbicide resistant cropping systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Over the last six decades, herbicides have been the mainstay of weed management in cropping systems around the world, especially in the Western Hemisphere. A direct consequence of intensive use of herbicides is the development of resistance in weed populations. The extreme popularity of transgenic g...

  11. Managing weeds in organic farming systems: an ecological approach

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Numerous investigators have concluded that improvements in weed management strategies that are minimally reliant on herbicides require the integration of multiple weed suppression tactics. However, the most cost-effective and efficacious ways to choose and combine tactics remain unclear. Here we sug...

  12. Post-directed weed control in bell peppers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic pepper (Capsicum annuum L.) producers need appropriate herbicides that can effectively provide post-emergent weed control. Research was conducted in southeast Oklahoma (Atoka County, Lane, OK) to determine the impact of a potential organic herbicide on weed control efficacy, crop injury, an...

  13. Molecular Biology and Genomics: New Tools for Weed Science

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Certain plant species are particularly well adapted to environments disturbed by humans. Often such species are invasive and problematic, and thus are classified as weeds. Despite our best efforts to control weeds, they continue to interfere with crop production. Clearly there is much to learn about...

  14. Impact of weed barriers on newly planted peach trees

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Newly planted (Feb. 2005) ‘Sunracer’ and ‘Sunhome’ nectarine and ‘Tropic Snow’ peach (Prunus persica (L.) Batsch) trees were subjected to conventional and four 'organic' weed control methods. Two of the 'organic' methods used weed barriers of white plastic (WP) or landscape fabric (LF). A third co...

  15. Weed management using goats: Effects on water infiltration rate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Goats are used increasingly for weed control, fire fuel reduction and ecological restoration. The high stocking rates typical of these applications have been reported to decrease the rate of water infiltration in goat pastures. The hypothesis that annual goat browsing for weed control decreases infi...

  16. Using Mustard Seed Meal and Cover Crops for Weed Control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There continues to be a steady growth in the use of fall planted brassica cover crops in the Columbia Basin especially prior to potatoes. Several benefits include better water infiltration, reclaiming nitrogen, reduced erosion, and suppression of nematodes, diseases, and weeds. Weed suppression is...

  17. Susceptibility of some common container weeds to Phytophthora ramorum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phytophthora ramorum is known to infect a number of ornamental plants grown in containerized culture. However, pots may also contain weeds. In this research, the foliage of 13 common weeds of containerized plant culture was inoculated with Phytophthora ramorum to determine susceptibility of above-...

  18. Herbicide-resistant crops, resistant weeds, and herbicide drift

    Technology Transfer Automated Retrieval System (TEKTRAN)

    New herbicide-resistance traits in corn and soybean may bring new management challenges for fruit and vegetable growers in the Mid-Atlantic region. Herbicide-resistant crops are an important weed management technology in row crop agriculture that allow growers to apply an herbicide to control weed...

  19. The Importance of Intertrophic Interactions in Biological Weed Control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The earliest research leading to successful weed biocontrol included observations and some analysis that the strict “gate-keeping” by peer reviewers, editors and publishers does not often allow today. Within these pioneering studies was a valid picture of the biology of weed biocontrol that is appli...

  20. Weed manipulation for insect pest management in corn

    NASA Astrophysics Data System (ADS)

    Altieri, M. A.; Whitcomb, W. H.

    1980-11-01

    Populations of insect pests and associated predaceous arthropods were sampled by direct observation and other relative methods in simple and diversified corn habitats at two sites in north Florida during 1978 and 1979. Through various cultural manipulations, characteristic weed communities were established selectively in alternate rows within corn plots. Fall armyworm ( Spodoptera frugiperda J. E. Smith) incidence was consistently higher in the weed-free habitats than in the corn habitats containing natural weed complexes or selected weed associations. Corn earworm ( Heliothis zea Boddie) damage was similar in all weed-free and weedy treatments, suggesting that this insect is not affected greatly by weed diversity. Only the diversification of corn with a strip of soybean significantly reduced corn earworm damage. In one site, distance between plots was reduced. Because predators moved freely between habitats, it was difficult to identify between-treatment differences in the composition of predator communities. In the other site, increased distances between plots minimized such migrations, resulting in greater population densities and diversity of common foliage insect predators in the weed-manipulated corn systems than in the weed-free plots. Trophic relationships in the weedy habitats were more complex than food webs in monocultures. Predator diversity (measured as mean number of species per area) and predator density was higher in com plots surrounded by mature, complex vegetation than at those surrounded by annual crops. This suggests that diverse adjacent areas to crops provide refuge for predators, thus acting as colonization sources.

  1. Organic weed control with vinegar: Application volumes and adjuvants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Preliminary results have indicated that vinegar has potential as an organic herbicide, but further research is needed to increase our understanding of the relationship between acetic acid concentrations, application volumes, adjuvants, weed species, and weed maturity on effectiveness of vinegar to c...

  2. Use of synthetic ground covers to control weeds in blackberries

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed control in blackberries (Rubus spp.) is a serious problem for organic producers and those who wish to reduce their reliance on herbicides. Three landscape fabrics (Dewitt, Texel, and a white polyester weave) and one industrial grade white on black plastic were used for weed control in conjucti...

  3. 7 CFR 360.200 - Designation of noxious weeds.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...) Aquatic and wetland weeds: Azolla pinnata R. Brown (mosquito fern, water velvet) Caulerpa taxifolia...-reed) (b) Parasitic weeds: Aeginetia spp. Alectra spp. Cuscuta spp. (dodders), other than following... vetchii Brandegee Cuscuta warneri Yuncker Orobanche spp. (broomrapes), other than the following...

  4. Organic weed management in vegetables: Research, experiences, and opportunities

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic farmers in a national survey ranked weed management as their greatest research need for organic crop production. Scientists from the Agriculture Research Service and Oklahoma State University have combined their efforts to conduct not only organic weed control research, but research involvi...

  5. Emerging Technologies: An Opportunity for Weed Biology Research

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The main objective of the Emerging Technologies Symposium at the 2007 WSSA Annual Meeting was to provide the weed science community with the principles behind emerging technologies and how they can be used to study weed biology. Specifically, aspects and applications related to genomic database deve...

  6. Weeds of the Midwestern United States and Central Canada

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The book, Weeds of the Central United States and Canada, includes 356 of the most common and/or troublesome weeds of agricultural and natural areas found within the central region of the United States and Canada. The books includes an introduction, a key to plant families contained in the book, glo...

  7. How to Identify and Control Water Weeds and Algae.

    ERIC Educational Resources Information Center

    Applied Biochemists, Inc., Mequon, WI.

    Included in this guide to water management are general descriptions of algae, toxic algae, weed problems in lakes, ponds, and canals, and general discussions of mechanical, biological and chemical control methods. In addition, pictures, descriptions, and recommended control methods are given for algae, 6 types of floating weeds, 18 types of…

  8. Working the Educational Soil and Pulling Up Weeds

    ERIC Educational Resources Information Center

    Riggins-Newby, Cheryl

    2005-01-01

    The job of an instructional leader, according to former Baltimore principal Deborah Wortham, is to be a gardener. School cultures left unattended, she says, sprout weeds that will eventually overwhelm the research-based programs, practices, and best efforts of teachers and administrators. The most aggressive and harmful educational weeds Wortham…

  9. 'Carolina' session: a major utilities program to manage aquatic weeds

    SciTech Connect

    Schiller, D.H.

    1984-06-01

    Carolina Power and Light Company has recently experienced aquatic weed problems in two of its impoundments. These problems have impacted power plant operations, water quality, and recreational activities. The Company is actively pursuing a program to deal with these weed problems through education, research, monitoring, and control activities.

  10. Mapping riparian and wetland weeds with high resolution satellite imagery

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aquatic and wetland weeds are a serious management problem in many freshwater ecosystems of the world. This paper presents an overview on the application of using high resolution QuickBird multi-spectral satellite imagery for detecting weeds in waterways and wetlands in Texas. Unsupervised image a...

  11. Weed science research and funding: a call to action

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed science has contributed much to agriculture, forestry and natural resource management over its history. However, if it is to remain relevant as a scientific discipline, it is long past time for weed scientists to take a step outside the “herbicide efficacy box” and address system-level issues i...

  12. Spectral reflectance and digital image relations among five aquatic weeds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study reports on the use of an artificial quartz halogen lighting source to facilitate the acquisition of spectral light reflectance measurements and digital imaging of invasive aquatic weeds. Spectral leaf or leaf/stem reflectance measurements were made on five aquatic weeds: Eurasian watermil...

  13. Mapping Invasive Aquatic and Wetland Weeds with Quickbird Satellite Imagery

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aquatic and wetland weeds are a serious management problem in many freshwater ecosystems of the world. This paper presents an overview on the application of using high resolution QuickBird multi-spectral satellite imagery for detecting weeds in waterways and wetlands in Texas. Unsupervised image a...

  14. Crop diversity sequencing can improve crop tolerance to weeds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The corn-soybean rotation in eastern South Dakota has led to a weed community comprised of species with similar life cycles to the crops; subsequently, weed management is a major input cost for producers. We are exploring crop diversity in this rotation to determine if producers can reduce the need...

  15. Cultivation strategies for weed control in organic peanut production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed management in organic peanut production is difficult and costly. Previous research demonstrated limitations of propane flaming and OMRI-approved herbicides suitable use in organic production. Furthermore, related studies clearly showed the inability to manage weeds in reduced-tillage organic ...

  16. Weed Community Emergence Pattern in Eastern South Dakota

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Producers who followed rotations comprised of crops with different growth periods are able to manage weeds with less herbicides. The diversity in growth periods provides more opportunities for producers to prevent weed seed production. In our research program, we are exploring impact of cool-seaso...

  17. Site-Specific Weed Management: Myth or Magic?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Site-specific weed management (SSWM) is a potential method to reduce the risks of herbicide use on water quality and public health without impacting crop yield. With site-specific weed management, areas of the field are left untreated where control is not economically justified. Where control is nee...

  18. Potential components for weed management in organic vegetable production systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic vegetable production relies on a variety of tactics for preventing losses to crop yield and quality that result from weed interference. These include field selection, long term field management, cultivation practices, mulching, and manual weeding to name a few. The concept of "herbicides" th...

  19. Corn gluten meal: Weed control and yields for onions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    One weed control option for certified organic producers is corn gluten meal (CGM). Field research was conducted in southeast Oklahoma (Lane, OK) to determine the efficacy of CGM as an herbicide for use in transplanted onion production. The research involved 8 weed control treatments with 4 replicat...

  20. Letting Go: How One Librarian Weeded a Children's Magazine Collection.

    ERIC Educational Resources Information Center

    Bromann, Jennifer

    2002-01-01

    Describes the weeding process for children's magazines in a public library. Highlights include circulation statistics; cost effectiveness; online availability; shelving magazines by subject to try and increase their use; and a chart that lists reasons to keep and reasons to cancel subscriptions when weeding a periodical collection. (LRW)

  1. Perpendicular cultivation for improved weed control in organic peanut production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Intensive cultivation in organic peanut is partially effective, but in-row weed control remains problematic. In an attempt to improve in-row weed control, trials were conducted to determine the feasibility of early-season cultivation perpendicular to row direction using a tine weeder when integrate...

  2. Evaluation of corn gluten meal for weed control in cowpea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Current weed control practices for cowpea production typically involve use of synthetic herbicides. Increasing interest in organic crop production creates a need for alternative weed control techniques that are consistent with requirements of the USDA National Organic Program. Corn gluten meal (CG...

  3. Use of cryptic species for biological control of weeds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Classical biological control of weeds depends on the discovery and evaluation of species of arthropods that are highly host specific. The rarity of such species in nature limits our ability to find safe effective agents to control a continually increasing list of invasive alien weeds. However, sci...

  4. Estimation of base temperatures for nine weed species.

    PubMed

    Steinmaus, S J; Prather, T S; Holt, J S

    2000-02-01

    Experiments were conducted to test several methods for estimating low temperature thresholds for seed germination. Temperature responses of nine weeds common in annual agroecosystems were assessed in temperature gradient experiments. Species included summer annuals (Amaranthus albus, A. palmeri, Digitaria sanguinalis, Echinochloa crus-galli, Portulaca oleracea, and Setaria glauca), winter annuals (Hirschfeldia incana and Sonchus oleraceus), and Conyza canadensis, which is classified as a summer or winter annual. The temperature below which development ceases (Tbase) was estimated as the x-intercept of four conventional germination rate indices regressed on temperature, by repeated probit analysis, and by a mathematical approach. An overall Tbase estimate for each species was the average across indices weighted by the reciprocal of the variance associated with the estimate. Germination rates increased linearly with temperature between 15 degrees C and 30 degrees C for all species. Consistent estimates of Tbase were obtained for most species using several indices. The most statistically robust and biologically relevant method was the reciprocal time to median germination, which can also be used to estimate other biologically meaningful parameters. The mean Tbase for summer annuals (13.8 degrees C) was higher than that for winter annuals (8.3 degrees C). The two germination response characteristics, Tbase and slope (rate), influence a species' germination behaviour in the field since the germination inhibiting effects of a high Tbase may be offset by the germination promoting effects of a rapid germination response to temperature. Estimates of Tbase may be incorporated into predictive thermal time models to assist weed control practitioners in making management decisions. PMID:10938833

  5. Weed Suppression by Seven Clover Species

    SciTech Connect

    Ross, Shirley M.; King, Jane R.; Izaurralde, R Cesar C.; O'Donovan, John T.

    2001-01-01

    Used as cover crops, clover species may differ in their ability to suppress weed growth. Field trials were conducted in Alberta, Canada to measure the growth of brown mustard [Brassica juncea (L.) Czern.], in mowed and nonmowed production, as influenced by alsike (Trifolium hybridum L.), balansa [T. michelianum Savi var. balansae (Boiss.) Azn.], berseem (T. alexandrinum L.), crimson [T. incarnatum (Boiss.) Azn.], berseem (T. alexandrinum L.), crimson (T. incarnatum L.), Persian (T. resupinatum L.), red (T. pratense L.), and white Dutch (T. repens L.) clover and fall rye (Secale cereale L.). In 1997, clovers reduced mustard biomass in nonmowed treatments by 29% on a high- fertility soil (Typic Cryoboroll) at Edmonton and by 57% on a low- fertility soil (Typic Cryoboralf) at Breton. At Edmonton, nonmowed mustard biomass was reduced by alsike and berseem clover in 1996 and by alsike, balansa, berseem, and crimson clover in 1997. At Breton, all seven clover species suppressed weed biomass. A negative correlation was noted among clover and mustard biomass at Edmonton but not at Breton. The effects of mowing varied with location, timing, and species. Mowing was beneficial to crop/weed proportion at Edmonton but not at Breton. Mowing at early flowering of mustard large-seeded legumes and sweetclover (Melilotus offici) produced greater benefit than mowing at late flowering. With early mowing, all clover species suppressed mustard growth at Edmonton. Clovers reduced mustard regrowth (g plant21 ) and the number of mustard plants producing regrowth. The characteristics of berseem clover (upright growth, long stems, high biomass, and late flowering) would support its use as a cover crop or forage in north-central Alberta.

  6. Hyperspectral image sensor for weed-selective spraying

    NASA Astrophysics Data System (ADS)

    Feyaerts, Filip; Pollet, P.; Van Gool, Luc J.; Wambacq, Patrick

    1999-11-01

    Recognizing, online, cops and weeds enables to reduce the use of chemicals in agriculture. First, a sensor and classifier is proposed to measure and classify, online, the plant reflectance. However, as plant reflectance varies with unknown field dependent plant stress factors, the classifier must be trained on each field separately in order to recognize crop and weeds accurately on that field. Collecting the samples manually requires user-knowledge and time and is therefore economically not feasible. The posed tree-based cluster algorithm enables to automatically collect and label the necessary set of training samples for crops that are planted in rows, thus eliminating every user- interaction and user-knowledge. The classifier, trained with the automatically collected and labeled training samples, is able to recognize crop and weeds with an accuracy of almost 94 percent. This result in acceptable weed hit rates and significant herbicide reductions. Spot-spraying on the weeds only becomes economically feasible.

  7. Spatial and Spectral Methods for Weed Detection and Localization

    NASA Astrophysics Data System (ADS)

    Vioix, Jean-Baptiste; Douzals, Jean-Paul; Truchetet, Frédéric; Assémat, Louis; Guillemin, Jean-Philippe

    2002-12-01

    This study concerns the detection and localization of weed patches in order to improve the knowledge on weed-crop competition. A remote control aircraft provided with a camera allowed to obtain low cost and repetitive information. Different processings were involved to detect weed patches using spatial then spectral methods. First, a shift of colorimetric base allowed to separate the soil and plant pixels. Then, a specific algorithm including Gabor filter was applied to detect crop rows on the vegetation image. Weed patches were then deduced from the comparison of vegetation and crop images. Finally, the development of a multispectral acquisition device is introduced. First results for the discrimination of weeds and crops using the spectral properties are shown from laboratory tests. Application of neural networks were mostly studied.

  8. RNAseq reveals weed-induced PIF3-like as a candidate target to manipulate weed stress response in soybean

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Research conducted, including the rationale: Weeds reduce yield in soybeans through incompletely defined mechanisms. The effects of weeds on the soybean transcriptome were evaluated in field conditions during four separate growing seasons. Methods: RNASeq data were collected from 6 biological sam...

  9. Current substances for organic weed control in vegetables or what do we have in our organic weed control tool box?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed control is the top research priority among organic producers. Organic producers have a short, but growing list of organic approved herbicides. The purpose of this publication is to provide general overview of weed control options for organic crop production. Research has demonstrated that co...

  10. PUTTING PLANT PATHOGENS TO WORK: PROGRESS AND POSSIBILITIES IN WEED BIOCONTROL PART 2. IMPROVING WEED CONTROL EFFICACY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The development of plant pathogenic weed biological control agents can be approached using two strategies, termed the classical and biological approaches. The classical involves the search for pathogens in the native range of an invasive weed and its importation and release into the area of introdu...

  11. Use of weeds as traditional vegetables in Shurugwi District, Zimbabwe

    PubMed Central

    2013-01-01

    Background Most agricultural weeds are usually regarded as undesirable and targeted for eradication. However, weeds are useful to human beings as food and traditional medicines. Few studies have been done to document the uses of weeds as traditional vegetables. This study was therefore, done to document indigenous knowledge related to the diversity and use of agricultural weeds as traditional vegetables in Shurugwi District, Zimbabwe, emphasizing their role in food security and livelihoods of the local people. Materials and methods Semi-structured interviews, observation and guided field walks with 147 participants were employed between December 2011 and January 2012 to obtain ethnobotanical data on the use of edible weeds as traditional vegetables. Based on ethnobotanical information provided by the participants, botanical specimens were collected, numbered, pressed and dried for identification. Results A total of 21 edible weeds belonging to 11 families and 15 genera, mostly from Amaranthaceae (19%), Asteraceae and Tiliaceae (14.3%), Capparaceae, Cucurbitaceae and Solanaceae (9.5% each) were identified. Of the documented edible weeds, 52.4% are indigenous while 47.6% are exotic to Zimbabwe; either semi-cultivated or growing naturally as agricultural weeds in farmlands, fallow land and home gardens. Among the main uses of edible weeds were leafy vegetables (81%), followed by edible fruits (19%), edible corms (9.5%), edible flowers and seeds (4.8% each). The most important edible weeds were Cleome gynandra, cited by 93.9% of the participants, Cucumis metuliferus (90.5%), Cucumis anguria (87.8%), Corchorus tridens (50.3%) and Amaranthus hybridus (39.5%). All edible weeds were available during rainy and harvest period with Cleome gynandra, Corchorus tridens, Cucumis anguria, Cucumis metuliferus and Moringa oleifera also available during the dry season, enabling households to obtain food outputs in different times of the year. The importance of edible weeds for local

  12. Managing Weeds in Potato Health Management, ed. D. Johnson. APS Press

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weeds must be managed throughout the entire crop rotation to optimize potato tuber yield and quality. Understanding factors that promote weed species and allow them to persist in crop rotations is key to designing cropping systems that discourage and reduce the impact of weeds. Weeds can be best man...

  13. Vinegar (20% acetic acid) broadcast application for broadleaf weed control in spring-transplanted onions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic weed control research was conducted in southeast Oklahoma to determine the effect of broadcast over-the-top applications of acetic acid (vinegar) on weed control efficacy, crop injury and onion yields. The experiment included 6 weed control treatments (2 application volumes, 2 hand-weeding ...

  14. 7 CFR 360.305 - Disposal of noxious weeds when permits are canceled.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 5 2013-01-01 2013-01-01 false Disposal of noxious weeds when permits are canceled... AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.305 Disposal of noxious weeds when permits are canceled. When a permit for the movement of a noxious weed...

  15. 7 CFR 360.300 - Notice of restrictions on movement of noxious weeds.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 5 2014-01-01 2014-01-01 false Notice of restrictions on movement of noxious weeds... AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.300 Notice of restrictions on movement of noxious weeds. No person may move a Federal noxious weed into...

  16. 7 CFR 360.300 - Notice of restrictions on movement of noxious weeds.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 5 2013-01-01 2013-01-01 false Notice of restrictions on movement of noxious weeds... AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.300 Notice of restrictions on movement of noxious weeds. No person may move a Federal noxious weed into...

  17. 7 CFR 360.305 - Disposal of noxious weeds when permits are canceled.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 5 2014-01-01 2014-01-01 false Disposal of noxious weeds when permits are canceled... AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.305 Disposal of noxious weeds when permits are canceled. When a permit for the movement of a noxious weed...

  18. 7 CFR 360.300 - Notice of restrictions on movement of noxious weeds.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 5 2011-01-01 2011-01-01 false Notice of restrictions on movement of noxious weeds... AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.300 Notice of restrictions on movement of noxious weeds. No person may move a Federal noxious weed into...

  19. 7 CFR 360.300 - Notice of restrictions on movement of noxious weeds.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 5 2012-01-01 2012-01-01 false Notice of restrictions on movement of noxious weeds... AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.300 Notice of restrictions on movement of noxious weeds. No person may move a Federal noxious weed into...

  20. 7 CFR 360.305 - Disposal of noxious weeds when permits are canceled.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 5 2011-01-01 2011-01-01 false Disposal of noxious weeds when permits are canceled... AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.305 Disposal of noxious weeds when permits are canceled. When a permit for the movement of a noxious weed...

  1. 7 CFR 360.305 - Disposal of noxious weeds when permits are canceled.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 5 2012-01-01 2012-01-01 false Disposal of noxious weeds when permits are canceled... AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.305 Disposal of noxious weeds when permits are canceled. When a permit for the movement of a noxious weed...

  2. Lawn Weeds and Their Control. North Central Regional Extension Publication No. 26.

    ERIC Educational Resources Information Center

    Purdue Univ., Lafayette, IN. Cooperative Extension Service.

    This publication discusses lawn weed control for the twelve state north central region of the country. Written for use by homeowners, the publication focuses on weed identification and proper herbicide selection and application. Identification of weeds and safe and appropriate herbicide use are emphasized. Forty-six weed and turf plants are…

  3. Early corn growth and development in response to weed, nitrogen, and shade stresses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Early season crop-weed interactions during a critical weed-free period (CWFP) influence corn growth that commonly results in reduced yield. Yield loss is not mitigated by weed removal after the CWFP, hence, weeds cause an irreversible negative impact on growth and development during the CWFP. Howeve...

  4. Economics of supplemental weed control applications on spring-transplanted onions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field research conducted to determine the relative benefits among alternative herbicides for weed control in onions (Allium cepa L.) measured weed control efficacy, impact of herbicides on crop injury, and the resulting weed competition on crop yields and marketable bulb size. Weed competition produ...

  5. Survival of weed seeds and animal parasites as affected by anaerobic digestion at meso- and thermophilic conditions.

    PubMed

    Johansen, Anders; Nielsen, Henrik B; Hansen, Christian M; Andreasen, Christian; Carlsgart, Josefine; Hauggard-Nielsen, Henrik; Roepstorff, Allan

    2013-04-01

    Anaerobic digestion of residual materials from animals and crops offers an opportunity to simultaneously produce bioenergy and plant fertilizers at single farms and in farm communities where input substrate materials and resulting digested residues are shared among member farms. A surplus benefit from this practice may be the suppressing of propagules from harmful biological pests like weeds and animal pathogens (e.g. parasites). In the present work, batch experiments were performed, where survival of seeds of seven species of weeds and non-embryonated eggs of the large roundworm of pigs, Ascaris suum, was assessed under conditions similar to biogas plants managed at meso- (37°C) and thermophilic (55°C) conditions. Cattle manure was used as digestion substrate and experimental units were sampled destructively over time. Regarding weed seeds, the effect of thermophilic conditions (55°C) was very clear as complete mortality, irrespective of weed species, was reached after less than 2 days. At mesophilic conditions, seeds of Avena fatua, Sinapsis arvensis, Solidago canadensis had completely lost germination ability, while Brassica napus, Fallopia convolvulus and Amzinckia micrantha still maintained low levels (~1%) of germination ability after 1 week. Chenopodium album was the only weed species which survived 1 week at substantial levels (7%) although after 11 d germination ability was totally lost. Similarly, at 55°C, no Ascaris eggs survived more than 3h of incubation. Incubation at 37°C did not affect egg survival during the first 48 h and it took up to 10 days before total elimination was reached. In general, anaerobic digestion in biogas plants seems an efficient way (thermophilic more efficient than mesophilic) to treat organic farm wastes in a way that suppresses animal parasites and weeds so that the digestates can be applied without risking spread of these pests. PMID:23266071

  6. Wallowa Canyonlands Weed Partnership : Completion Report November 19, 2009

    SciTech Connect

    Porter, Mark C.; Ketchum, Sarah

    2008-12-30

    Noxious weeds threaten fish and wildlife habitat by contributing to increased sedimentation rates, diminishing riparian structure and function, and reducing forage quality and quantity. Wallowa Resources Wallowa Canyonlands Partnership (WCP) protects the unique ecological and economic values of the Hells Canyon grasslands along lower Joseph Creek, the lower Grande Ronde and Imnaha Rivers from invasion and degradation by noxious weeds using Integrated Weed Management techniques. Objectives of this grant were to inventory and map high priority weeds, coordinate treatment of those weeds, release and monitor bio-control agents, educate the public as to the dangers of noxious weeds and how to deal with them, and restore lands to productive plant communities after treatment. With collaborative help from partners, WCP inventoried {approx} 215,000 upland acres and 52.2 miles of riparian habitat, released bio-controls at 23 sites, and educated the public through posters, weed profiles, newspaper articles, and radio advertisements. Additionally, WCP used other sources of funding to finance the treatment of 1,802 acres during the course of this grant.

  7. Capabilities of unmanned aircraft vehicles for low altitude weed detection

    NASA Astrophysics Data System (ADS)

    Pflanz, Michael; Nordmeyer, Henning

    2014-05-01

    Sustainable crop production and food security require a consumer and environmental safe plant protection. It is recently known, that precise weed monitoring approaches could help apply pesticides corresponding to field variability. In this regard the site-specific weed management may contribute to an application of herbicides with higher ecologically aware and economical savings. First attempts of precision agriculture date back to the 1980's. Since that time, remote sensing from satellites or manned aircrafts have been investigated and used in agricultural practice, but are currently inadequate for the separation of weeds in an early growth stage from cultivated plants. In contrast, low-cost image capturing at low altitude from unmanned aircraft vehicles (UAV) provides higher spatial resolution and almost real-time processing. Particularly, rotary-wing aircrafts are suitable for precise path or stationary flight. This minimises motion blur and provides better image overlapping for stitching and mapping procedures. Through improved image analyses and the recent increase in the availability of microcontrollers and powerful batteries for UAVs, it can be expected that the spatial mapping of weeds will be enhanced in the future. A six rotors microcopter was equipped with a modified RGB camera taking images from agricultural fields. The hexacopter operates within predefined pathways at adjusted altitudes (from 5 to 10 m) by using GPS navigation. Different scenarios of optical weed detection have been carried out regarding to variable altitude, image resolution, weed and crop growth stages. Our experiences showed high capabilities for site-specific weed control. Image analyses with regard to recognition of weed patches can be used to adapt herbicide application to varying weed occurrence across a field.

  8. Evaluation of biomass of some invasive weed species as substrate for oyster mushroom (Pleurotus spp.) cultivation.

    PubMed

    Mintesnot, Birara; Ayalew, Amare; Kebede, Ameha

    2014-01-15

    This study assessed the bioconversion of Agriculture wastes like invasive weeds species (Lantana camara, Prosopis juliflora, Parthenium hysterophorus) as a substrate for oyster mushroom (Pleurotus species) cultivation together with wheat straw as a control. The experiment was laid out in factorial combination of substrates and three edible oyster mushroom species in a Completely Randomized Design (CRD) with three replications. Pleurotus ostreatus gave significantly (p < 0.01) total yield of 840 g kg(-1) on P. hysterophorus, Significantly (p < 0.01) biological efficiency (83.87%) and production rate of 3.13 was recorded for P. ostreatus grown on P. hysterophorus. The highest total ash content (13.90%) was recorded for P. florida grown on L. camara. while the lowest (6.92%) was for P. sajor-caju grown on the P. juliflora. Crude protein ranged from 40.51-41.48% for P. florida grown on P. hysterophorus and L. camara. Lowest crude protein content (30.11%) was recorded for P. ostreatus grown on wheat straw. The crude fiber content (12.73%) of P. sajor-caju grown on wheat straw was the highest. The lowest crude fiber (5.19%) was recorded for P. ostreatus on P. juliflora. Total yield had a positive and significant correlation with biological efficiency and production. Utilization of the plant biomass for mushroom cultivation could contribute to alleviating ecological impact of invasive weed species while offering practical option to mitigating hunger and malnutrition in areas where the invasive weeds became dominant. PMID:24783804

  9. Soil solarization reduces arbuscular mycorrhizal fungi as a consequence of weed suppression.

    PubMed

    Schreiner, P R; Ivors, K L; Pinkerton, J N

    2001-12-01

    Soil solarization, the process of heating soil by covering fields with clear plastic, is a promising method to reduce populations of soilborne pests and weeds without the use of pesticides. However, the destruction of beneficial organisms such as arbuscular mycorrhizal (AM) fungi also may occur, thereby reducing positive effects of solarization. We compared the effects of solarization and chemical fumigants on the survival of indigenous AM fungi in 1995 and 1996. The infectivity of AM fungi was monitored before and after solarization using a greenhouse bioassay with Sorghum bicolor L. for both years. AM colonization of roots was also monitored in the field 8 months after solarization in 1995. Weed densities were measured 8 months after treatment in 1996. Solarization increased the average daily soil temperature 6-10°C and the maximum soil temperature reached by 10-16°C (5-20 cm depth). Solarization did not reduce the infectivity of AM fungi immediately after the solarization period in either year, as determined by the greenhouse bioassay. Infectivity was greatly reduced in solarized plots 8 months after solarization (over winter) in both years as assessed in the field (1995) or with the greenhouse bioassay (1996). Fumigation with metam sodium at 930 l ha(-1) (350 kg active ingredient ha(-1)) reduced the infectivity of AM fungi in both years, and fumigation with methyl bromide at 800 kg ha(-1) eliminated infection by AM fungi. Solarization was as effective as methyl bromide and metam sodium at 930 l ha(-1) in controlling winter annual weeds measured 8 months after treatment. Solarization apparently reduced AM fungi in soil indirectly by reducing weed populations that maintained infective propagules over the winter. Fumigation with metam sodium or methyl bromide directly reduced AM fungi in soil. PMID:24549346

  10. Weed Control Sprayers: Calibration and Maintenance. Special Circular 81.

    ERIC Educational Resources Information Center

    Myers, Arthur L.

    This manual covers aspects of calibration and maintenance of weed control sprayers including variables affecting application rate, the pre-calibration check, calculations, band spraying, nozzle tip selection, agitation, and cleaning. (BB)

  11. Cultural control of weeds in herbicide-free annual forages

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The adoption of zero tillage systems improves soil water conservation, allowing for increased crop intensification and diversification in the semiarid northern Great Plains. Zero tillage systems rely primarily on herbicides for weed management, increasing selection pressure for herbicide resistance...

  12. DEVELOPING WEED SUPPRESSIVE SOILS THROUGH IMPROVED SOIL QUALITY MANAGEMENT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sustainable agriculture is based in part on efficient management of soil microorganisms for improving soil quality. However, identification of biological indicators of soil quality for predicting weed suppression in soils has received little attention. We investigated differences in soil microbial ...

  13. Mapping invasive weeds and their control with spatial information technologies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We discuss applications of airborne multispectral digital imaging systems, imaging processing techniques, global positioning systems (GPS), and geographic information systems (GIS) for mapping the invasive weeds giant salvinia (Salvinia molesta) and Brazilian pepper (Schinus terebinthifolius) and fo...

  14. The biology of habitat dominance; can microbes behave as weeds?

    PubMed

    Cray, Jonathan A; Bell, Andrew N W; Bhaganna, Prashanth; Mswaka, Allen Y; Timson, David J; Hallsworth, John E

    2013-09-01

    Competition between microbial species is a product of, yet can lead to a reduction in, the microbial diversity of specific habitats. Microbial habitats can resemble ecological battlefields where microbial cells struggle to dominate and/or annihilate each other and we explore the hypothesis that (like plant weeds) some microbes are genetically hard-wired to behave in a vigorous and ecologically aggressive manner. These 'microbial weeds' are able to dominate the communities that develop in fertile but uncolonized--or at least partially vacant--habitats via traits enabling them to out-grow competitors; robust tolerances to habitat-relevant stress parameters and highly efficient energy-generation systems; avoidance of or resistance to viral infection, predation and grazers; potent antimicrobial systems; and exceptional abilities to sequester and store resources. In addition, those associated with nutritionally complex habitats are extraordinarily versatile in their utilization of diverse substrates. Weed species typically deploy multiple types of antimicrobial including toxins; volatile organic compounds that act as either hydrophobic or highly chaotropic stressors; biosurfactants; organic acids; and moderately chaotropic solutes that are produced in bulk quantities (e.g. acetone, ethanol). Whereas ability to dominate communities is habitat-specific we suggest that some microbial species are archetypal weeds including generalists such as: Pichia anomala, Acinetobacter spp. and Pseudomonas putida; specialists such as Dunaliella salina, Saccharomyces cerevisiae, Lactobacillus spp. and other lactic acid bacteria; freshwater autotrophs Gonyostomum semen and Microcystis aeruginosa; obligate anaerobes such as Clostridium acetobutylicum; facultative pathogens such as Rhodotorula mucilaginosa, Pantoea ananatis and Pseudomonas aeruginosa; and other extremotolerant and extremophilic microbes such as Aspergillus spp., Salinibacter ruber and Haloquadratum walsbyi. Some microbes

  15. Crop performance and weed suppression by weed-suppressive rice cultivars in furrow- and flood-irrigated systems under reduced herbicide inputs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed control in rice is challenging, particularly in light of increased resistance to herbicides in weed populations and diminishing availability of irrigation water. Certain indica rice cultivars can produce high yields and suppress weeds in conventional flood-irrigated, drill-seeded systems in the...

  16. Herbicide-resistant crops and weed resistance to herbicides.

    PubMed

    Owen, Micheal D K; Zelaya, Ian A

    2005-03-01

    The adoption of genetically modified (GM) crops has increased dramatically during the last 3 years, and currently over 52 million hectares of GM crops are planted world-wide. Approximately 41 million hectares of GM crops planted are herbicide-resistant crops, which includes an estimated 33.3 million hectares of herbicide-resistant soybean. Herbicide-resistant maize, canola, cotton and soybean accounted for 77% of the GM crop hectares in 2001. However, sugarbeet, wheat, and as many as 14 other crops have transgenic herbicide-resistant cultivars that may be commercially available in the near future. There are many risks associated with the production of GM and herbicide-resistant crops, including problems with grain contamination, segregation and introgression of herbicide-resistant traits, marketplace acceptance and an increased reliance on herbicides for weed control. The latter issue is represented in the occurrence of weed population shifts, the evolution of herbicide-resistant weed populations and herbicide-resistant crops becoming volunteer weeds. Another issue is the ecological impact that simple weed management programs based on herbicide-resistant crops have on weed communities. Asiatic dayflower (Commelina cumminus L) common lambsquarters (Chenopodium album L) and wild buckwheat (Polygonum convolvulus L) are reported to be increasing in prominence in some agroecosystems due to the simple and significant selection pressure brought to bear by herbicide-resistant crops and the concomitant use of the herbicide. Finally, evolution of herbicide-resistant weed populations attributable to the herbicide-resistant crop/herbicide program has been observed. Examples of herbicide-resistant weeds include populations of horseweed (Conyza canadensis (L) Cronq) resistant to N-(phosphonomethyl)glycine (glyphosate). An important question is whether or not these problems represent significant economic issues for future agriculture. PMID:15668920

  17. Robust Crop and Weed Segmentation under Uncontrolled Outdoor Illumination

    PubMed Central

    Jeon, Hong Y.; Tian, Lei F.; Zhu, Heping

    2011-01-01

    An image processing algorithm for detecting individual weeds was developed and evaluated. Weed detection processes included were normalized excessive green conversion, statistical threshold value estimation, adaptive image segmentation, median filter, morphological feature calculation and Artificial Neural Network (ANN). The developed algorithm was validated for its ability to identify and detect weeds and crop plants under uncontrolled outdoor illuminations. A machine vision implementing field robot captured field images under outdoor illuminations and the image processing algorithm automatically processed them without manual adjustment. The errors of the algorithm, when processing 666 field images, ranged from 2.1 to 2.9%. The ANN correctly detected 72.6% of crop plants from the identified plants, and considered the rest as weeds. However, the ANN identification rates for crop plants were improved up to 95.1% by addressing the error sources in the algorithm. The developed weed detection and image processing algorithm provides a novel method to identify plants against soil background under the uncontrolled outdoor illuminations, and to differentiate weeds from crop plants. Thus, the proposed new machine vision and processing algorithm may be useful for outdoor applications including plant specific direct applications (PSDA). PMID:22163954

  18. Characterization of a non-chemically amplified resist for photomask fabrication using a 257-nm optical pattern generator

    NASA Astrophysics Data System (ADS)

    Rathsack, Benjamen M.; Tabery, Cyrus E.; Stachowiak, Timothy B.; Dallas, Tim E.; Xu, Cheng-Bai; Pochkowski, Mike; Willson, C. Grant

    1999-12-01

    I-line optical pattern generators using non-chemically amplified resists have become the workhorses for high throughput mask fabrication. The demand for smaller and more uniform features on photomasks has driven the development of a 257 nm optical pattern generator. A non-chemically amplified resist is being developed to maximize the performance of this new 257 nm mask tool. Resist characterization and lithography simulation are being used to formulate a non-chemically amplified resist for 257 nm optical pattern generators. Non- chemically amplified resists are advantageous for us in mask fabrication due to their storage and post-exposure stability. Chemically amplified resists may provide higher performance but they also require environmental mini-environments and a post-exposure bake equipment not commonly present in mask houses. Diazonaphthoquinone (DNQ)/novolak resists have not been used for DUV Integrated Circuit (IC) applications mainly due to the low sensitivity and the strong absorbance of the DNQ photoactive compound (PAC) at 248 nm. However, a 2,1,4 DNQ based resist has been characterized that bleaches at 257 nm and inhibits novolak. The photoproduct of the 2,1,4 DNQ PAC is much more transparent at 257 nm than 248 nm. Novolak resin is too strongly absorbing for use in formulating efficient 248 nm resists, but novolak has an absorbance minimum at 257 nm that provides transparency similar to poly (hydroxystyrene). Lithography simulation is being used to develop a non- chemically amplified resist to minimize the expensive iteration of manufacturing trials. An exposure system using a 257 nm frequency double Ar laser system has been constructed to study the resist photokinetics. Dill exposure parameters (A, B and C) have been extracted for a 2,1,4 DNQ/novolak based resist. Dissolution rate measurements have been made with a DRM developed at the University of Texas at Austin. Simulation is used to determine the optimal resist absorption, bleaching, dose and

  19. Effect of tillage system on yield and weed populations of soybean ( Glycin Max L.).

    PubMed

    Hosseini, Seyed Z; Firouzi, Saeed; Aminpanah, Hashem; Sadeghnejhad, Hamid R

    2016-03-01

    Field experiment was conducted at Agricultural and Natural Resources Research Center of Golestan Province, Iran, to determine the effects of tillage system and weed management regime on yield and weed populations in soybean ( Glycin max L.). The experimental design was a split plot where the whole plot portion was a randomized complete block with three replicates. Main plots were tillage system: 1- No-till row crop seeding, 2- No-till seed drilling, 3- Tillage with disc harrow and drill planting, 4- Tillage with chisel packer and drill planting. The subplots were weed management regimes: 1-Weed control with herbicide application, 2- Hand weeding, 3- Herbicide application plus hand weeding, and 4- Non-weeding. Results indicated that the main effects of tillage system and weed management regime were significant for seed yield, pod number per plant, seed number per pod, weed density and biomass, while their interaction were significant only for weed density, weed biomass, and seed number per pod. The highest grain yields (3838 kg ha-1) were recorded for No-till row crop seeding. The highest seed yield (3877 kg ha-1) also was recorded for weed control with herbicide and hand weeding treatment, followed by hand weeding (3379 kg ha-1). PMID:26871488

  20. Interspecific variation in persistence of buried weed seeds follows trade-offs among physiological, chemical and physical seed defences

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil seedbanks drive infestations of annual weeds, yet weed management focuses largely on seedling mortality. As weed seedbanks increasingly become reservoirs of herbicide resistance, species-specific seedbank management approaches will be essential. Limited understanding of interspecific variation ...

  1. The biology of habitat dominance; can microbes behave as weeds?

    PubMed Central

    Cray, Jonathan A; Bell, Andrew N W; Bhaganna, Prashanth; Mswaka, Allen Y; Timson, David J; Hallsworth, John E

    2013-01-01

    Summary Competition between microbial species is a product of, yet can lead to a reduction in, the microbial diversity of specific habitats. Microbial habitats can resemble ecological battlefields where microbial cells struggle to dominate and/or annihilate each other and we explore the hypothesis that (like plant weeds) some microbes are genetically hard-wired to behave in a vigorous and ecologically aggressive manner. These ‘microbial weeds’ are able to dominate the communities that develop in fertile but uncolonized – or at least partially vacant – habitats via traits enabling them to out-grow competitors; robust tolerances to habitat-relevant stress parameters and highly efficient energy-generation systems; avoidance of or resistance to viral infection, predation and grazers; potent antimicrobial systems; and exceptional abilities to sequester and store resources. In addition, those associated with nutritionally complex habitats are extraordinarily versatile in their utilization of diverse substrates. Weed species typically deploy multiple types of antimicrobial including toxins; volatile organic compounds that act as either hydrophobic or highly chaotropic stressors; biosurfactants; organic acids; and moderately chaotropic solutes that are produced in bulk quantities (e.g. acetone, ethanol). Whereas ability to dominate communities is habitat-specific we suggest that some microbial species are archetypal weeds including generalists such as: Pichia anomala, Acinetobacter spp. and Pseudomonas putida; specialists such as Dunaliella salina, Saccharomyces cerevisiae, Lactobacillus spp. and other lactic acid bacteria; freshwater autotrophs Gonyostomum semen and Microcystis aeruginosa; obligate anaerobes such as Clostridium acetobutylicum; facultative pathogens such as Rhodotorula mucilaginosa, Pantoea ananatis and Pseudomonas aeruginosa; and other extremotolerant and extremophilic microbes such as Aspergillus spp., Salinibacter ruber and Haloquadratum walsbyi

  2. Tillage and residue burning affects weed populations and seed banks.

    PubMed

    Narwal, S; Sindel, B M; Jessop, R S

    2006-01-01

    An integrated weed management approach requires alternative management practices to herbicide use such as tillage, crop rotations and cultural controls to reduce soil weed seed banks. The objective of this study was to examine the value of different tillage practices and stubble burning to exhaust the seed bank of common weeds from the northern grain region of Australia. Five tillage and burning treatments were incorporated in a field experiment, at Armidale (30 degrees 30'S, 151 degrees 40'E), New South Wales, Australia in July 2004 in a randomized block design replicated four times. The trial was continued and treatments repeated in July 2005 with all the mature plants from the first year being allowed to shed seed in their respective treatment plots. The treatments were (i) no tillage (NT), (ii) chisel ploughing (CP), (iii) mould board ploughing (MBP), (iv) wheat straw burning with no tillage (SBNT) and (v) wheat straw burning with chisel ploughing (SBC). Soil samples were collected before applying treatments and before the weeds flowered to establish the seed bank status of the various weeds in the soil. Wheat was sown after the tillage treatments. Burning treatments were only initiated in the second year, one month prior to tillage treatments. The major weeds present in the seed bank before initiating the trial were Polygonum aviculare, Sonchus oleraceus and Avena fatua. Tillage promoted the germination of other weeds like Hibiscus trionum, Medicago sativa, Vicia sp. and Phalaris paradoxa later in the season in 2004 and Convolvulus erubescens emerged as a new weed in 2005. The MBP treatment in 2004 reduced the weed biomass to a significantly lower level of 55 g/m2 than the other treatments of CP (118 g/m2) and NT plots (196 g/m2) (P < 0.05). However, in 2005 SBC and MBP treatments were similar in reducing the weed biomass. In 2004, the grain yield trend of wheat was significantly different between CP and NT, and MBP and NT (P < 0.05) with maximum yield of 5898

  3. Microfungal "weeds" in the leafcutter ant symbiosis.

    PubMed

    Rodrigues, A; Bacci, M; Mueller, U G; Ortiz, A; Pagnocca, F C

    2008-11-01

    Leafcutter ants (Formicidae: tribe Attini) are well-known insects that cultivate basidiomycete fungi (Agaricales: Lepiotaceae) as their principal food. Fungus gardens are monocultures of a single cultivar strain, but they also harbor a diverse assemblage of additional microbes with largely unknown roles in the symbiosis. Cultivar-attacking microfungi in the genus Escovopsis are specialized parasites found only in association with attine gardens. Evolutionary theory predicts that the low genetic diversity in monocultures should render ant gardens susceptible to a wide range of diseases, and additional parasites with roles similar to that of Escovopsis are expected to exist. We profiled the diversity of cultivable microfungi found in 37 nests from ten Acromyrmex species from Southern Brazil and compared this diversity to published surveys. Our study revealed a total of 85 microfungal strains. Fusarium oxysporum and Escovopsis were the predominant species in the surveyed gardens, infecting 40.5% and 27% of the nests, respectively. No specific relationship existed regarding microfungal species and ant-host species, ant substrate preference (dicot versus grass) or nesting habit. Molecular data indicated high genetic diversity among Escovopsis isolates. In contrast to the garden parasite, F. oxysporum strains are not specific parasites of the cultivated fungus because strains isolated from attine gardens have similar counterparts found in the environment. Overall, the survey indicates that saprophytic microfungi are prevalent in South American leafcutter ants. We discuss the antagonistic potential of these microorganisms as "weeds" in the ant-fungus symbiosis. PMID:18369523

  4. PERENNIAL CROP NURSERIES TREATED WITH METHYL BROMIDE AND ALTERNATIVE FUMIGANTS: EFFECTS ON WEED SEED VIABILITY, WEED DENSITIES, AND TIME REQUIRED FOR HAND WEEDING

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed control provided by alternative fumigants to methyl bromide (MeBr) needs to be tested in perennial crop nurseries in California because MeBr is being phased out in accordance with the Montreal Protocol, few herbicides are registered for perennial nursery use, and costs of other control measures...

  5. Utility of remote sensing for soybean and weed species differentiation

    NASA Astrophysics Data System (ADS)

    Gray, Cody Jack

    Weeds are typically found in aggregated patches within a production area. Remote sensing technologies have been incorporated into agricultural production systems to locate and manage these troublesome areas site-specifically. Correct weed identification is a key component when making proper weed control decisions. Research was implemented to evaluate the use of hyperspectral and multispectral reflectance data for proper weed and crop discrimination. The primary objectives of this research were to evaluate the utility of hyperspectral radiometry and multispectral imagery to differentiate soybean and six weed species commonly found in Mississippi. Additional objectives included evaluating the spectral characteristics of Palmer amaranth and pitted morningglory accessions collected across central and southern United States. Principal component analysis was ineffective in discriminating between species. Best spectral band combination analysis (BSBC) produced the greatest weed classification accuracies when comparing all classification techniques. The BSBC suggested three areas of interest for species discrimination in the short wavelength infrared portion of the electromagnetic spectrum. These areas of interest were located from 1445 to 1475 nm, 2030 to 2090 nm, and 2115 to 2135 nm. Classification accuracies increased for all species when these band regions were added than when using vegetation indices alone, suggesting greater crop and weed species differentiation can be obtained when using sensors that include these regions of the short wavelength infrared portion of the electromagnetic spectrum. Three supervised classification systems were implemented in multispectral imagery classification. The best classification accuracies of 90% or greater were obtained for many of the plant species at 10 and 12 weeks after emergence using either a 2-class or 3-class system. Palmleaf morningglory and pitted morningglory at the highest densities of 6 plants/m2 produced the highest

  6. EFFECTS OF ORGANIC AND CONVENTIONAL PRACTICES ON WEED CONTROL IN A PERENNIAL CROPPING SYSTEM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vineyard weed communities were examined under the influence of an organic weed control practice, soil cultivation with a Clemens cultivator, and applications of the herbicide, glyphosate. Experimental treatments (winter-spring glyphosate, spring cultivation, fall-spring cultivation, fall cultivatio...

  7. Linkages Among Agronomic, Environmental and Weed Management Characteristics in North American Sweet Corn

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Performance of weed management systems varies greatly across the landscape in both growers’ fields and in experimental trials conducted by agricultural scientists. Using agronomic, environmental, and weed management information from growers’ fields and experimental trials, we identified dominant ch...

  8. N-(2-bromophenyl)-2-(4,6-dimethoxypyrimidin-2-yloxy)benzylamine, a new selective postemergent herbicide for weed control in winter oilseed rape.

    PubMed

    Wu, Jun; Cheng, Jie; Lu, Long

    2006-08-01

    N-(2-Bromophenyl)-2-(4,6-dimethoxypyrimidin-2-yloxy)benzylamine is a highly active herbicide, which belongs to a novel class of chemistry. The compound is de novo synthesized in good yield, and the structure is confirmed by (1)H NMR, IR, MS, microanalysis, and X-ray. Its herbicidal activity is assessed under greenhouse conditions. It is effective against many grass weed species, as well as broadleaf weeds, under greenhouse conditions. Field trials indicate that it controls major weeds with a good tolerance on oilseed rape by postemergence application at rates of 15-90 g of active ingredient/ha. This compound possesses low mammalian toxicity and favorable environmental profile. These results suggest that the compound has potential as a new selective postemergent herbicide in winter oilseed rape. PMID:16881700

  9. Classification of Maize and Weeds by Bayesian Networks

    NASA Astrophysics Data System (ADS)

    Chapron, Michel; Oprea, Alina; Sultana, Bogdan; Assemat, Louis

    2007-11-01

    Precision Agriculture is concerned with all sorts of within-field variability, spatially and temporally, that reduces the efficacy of agronomic practices applied in a uniform way all over the field. Because of these sources of heterogeneity, uniform management actions strongly reduce the efficiency of the resource input to the crop (i.e. fertilization, water) or for the agrochemicals use for pest control (i.e. herbicide). Moreover, this low efficacy means high environmental cost (pollution) and reduced economic return for the farmer. Weed plants are one of these sources of variability for the crop, as they occur in patches in the field. Detecting the location, size and internal density of these patches, along with identification of main weed species involved, open the way to a site-specific weed control strategy, where only patches of weeds would receive the appropriate herbicide (type and dose). Herein, an automatic recognition method of vegetal species is described. First, the pixels of soil and vegetation are classified in two classes, then the vegetation part of the input image is segmented from the distance image by using the watershed method and finally the leaves of the vegetation are partitioned in two parts maize and weeds thanks to the two Bayesian networks.

  10. Research on crop and weed identification by NIR spectroscopy

    NASA Astrophysics Data System (ADS)

    Pan, Jiazhi; Tang, Yueming; He, Yong

    2007-01-01

    Crop and weed identification is very importance in precision farming field. As spectroscopy can reflects the contents of object tested, so it is possible to identify crop and weed with high correct rate. ASD FieldSpec recorded the spectrum of crops and weeds. Its waveband is 325-1075nm and with resolution of 3.5nm. One crop seedling and three kinds of weeds living together were tested. Each species has at least 30 sampling spectrum taken down. As one sample spectrum has too much data, wavelet transform reduced the data volume firstly, which compressed source signals to tens of floating numbers from 751 floating numbers. Totally 160 samples were used to build a radial basis function neural network, the object output was a 4 by 1 dimension vector. Those left 43 samples used to check the identifying capability. As neural network model has huge power in solving these pattern recognition problems. It can approach to giving finite function at any approximation. Nearly all these predicting samples classified right. Therefore, by using spectroscopy in the identification is possible, and having high correct rate. Further more, the computation is very fast. Whereas the spectrometer is expensive and easily affected by shaking and variation of light shine, it cannot installed directly on vehicles at present time. In the future, it may be possible to recognize crop and weed in real time by using spectroscopy.

  11. Controlling weeds with fungi, bacteria and viruses: a review.

    PubMed

    Harding, Dylan P; Raizada, Manish N

    2015-01-01

    Weeds are a nuisance in a variety of land uses. The increasing prevalence of both herbicide resistant weeds and bans on cosmetic pesticide use has created a strong impetus to develop novel strategies for controlling weeds. The application of bacteria, fungi and viruses to achieving this goal has received increasingly great attention over the last three decades. Proposed benefits to this strategy include reduced environmental impact, increased target specificity, reduced development costs compared to conventional herbicides and the identification of novel herbicidal mechanisms. This review focuses on examples from North America. Among fungi, the prominent genera to receive attention as bioherbicide candidates include Colletotrichum, Phoma, and Sclerotinia. Among bacteria, Xanthomonas and Pseudomonas share this distinction. The available reports on the application of viruses to controlling weeds are also reviewed. Focus is given to the phytotoxic mechanisms associated with bioherbicide candidates. Achieving consistent suppression of weeds in field conditions is a common challenge to this control strategy, as the efficacy of a bioherbicide candidate is generally more sensitive to environmental variation than a conventional herbicide. Common themes and lessons emerging from the available literature in regard to this challenge are presented. Additionally, future directions for this crop protection strategy are suggested. PMID:26379687

  12. Controlling weeds with fungi, bacteria and viruses: a review

    PubMed Central

    Harding, Dylan P.; Raizada, Manish N.

    2015-01-01

    Weeds are a nuisance in a variety of land uses. The increasing prevalence of both herbicide resistant weeds and bans on cosmetic pesticide use has created a strong impetus to develop novel strategies for controlling weeds. The application of bacteria, fungi and viruses to achieving this goal has received increasingly great attention over the last three decades. Proposed benefits to this strategy include reduced environmental impact, increased target specificity, reduced development costs compared to conventional herbicides and the identification of novel herbicidal mechanisms. This review focuses on examples from North America. Among fungi, the prominent genera to receive attention as bioherbicide candidates include Colletotrichum, Phoma, and Sclerotinia. Among bacteria, Xanthomonas and Pseudomonas share this distinction. The available reports on the application of viruses to controlling weeds are also reviewed. Focus is given to the phytotoxic mechanisms associated with bioherbicide candidates. Achieving consistent suppression of weeds in field conditions is a common challenge to this control strategy, as the efficacy of a bioherbicide candidate is generally more sensitive to environmental variation than a conventional herbicide. Common themes and lessons emerging from the available literature in regard to this challenge are presented. Additionally, future directions for this crop protection strategy are suggested. PMID:26379687

  13. The Identification and Role of Non-Chemical Stressors as Modifiers of Chemical Exposures that Lead to Changes in Health and Well-Being in Children

    EPA Science Inventory

    Describe the Sustainable and Health Communities (SHC) Research Program at the U.S. EPA Discuss non-chemical stressors found in the social environment, What are they? Why are they important? Summarize current and planned work

  14. Effect of mechanical damage on emission of volatile organic compounds from plant leaves and implications for evaluation of host plant specificity of prospective biological control agents of weeds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Assessment of host plant specificity is a critical step in the evaluation of classical biological control agents of weeds, which is necessary for avoiding possible damage to nontarget plants. Volatile organic compounds (VOC) emitted by plants likely play an important role in determining which plant...

  15. Cultural practices to improve in-row weed control with cultivation in organic peanut production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cultivation is a proven effective means of weed control in organic peanut. However, weeds in-row often escape control. Research trials were conducted in Ty Ty, GA to modify cultural practices to help peanut suppress weed emergence in-row. Modified cultural practices were three row pattern/seeding...

  16. Sweat, Brain-Power, Horsepower, and Time - The Keys to Controlling Weeds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed control in organic crop production is difficult and costly. Early studies on organic weed control in conservation tillage systems were disappointing. Research shifted to organic weed control in conventional tillage systems. Intense cultivation with a tine weeder was the most consistent metho...

  17. Establishing a weed prevention area, a step-by-step user's guide

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Traditionally, weed management activities are only initiated after a weed has become a major economic problem in an area. This guide provides a process for individuals interested in developing community based weed prevention areas (WPA) to take a proactive approach to invasive species management. ...

  18. Organic Highbush Blueberry Production Systems Research – Management of Plant Nutrition, Irrigation Requirements, and Weeds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A 0.4 ha planting of blueberry was established in October 2006 to evaluate the effects of cultivar (Duke and Liberty), bed type (flat versus raised beds), weed management (sawdust mulch and hand-weed control; sawdust+compost mulch with acetic acid, flaming, and hand control used as needed; and weed ...

  19. AXXE® (pelargonic acid) and Racer® (ammonium nonanoate): Weed control comparisons

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic vegetable producers need herbicides that can provide effective season-long weed control. The availability and use of effective post-emergence organic herbicides would increase the likelihood of season-long weed control, reduce crop loses, and decrease the introduction of additional weed seed...

  20. Economics of weed suppressive rice cultivars in flood- and furrow-irrigated systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weeds are a major constraint to rice production. In the U.S, weeds in rice are controlled primarily with synthetic herbicides. Intensive herbicide application in rice also has many potential drawbacks, resulting in environmental pollution, human health concerns, and development of weed resistance. B...

  1. Changes in the weed species composition of the southern US: 1995 to 2009

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Changes in the weed flora of crops reflect not only the influx and losses to the soil seedbank, but also the management impacts. This analysis documents the changes in the weed flora of the 14 contiguous states comprising the Southern Weed Science Society since the advent of transgenic, herbicide re...

  2. Broadcast application of Racer for broadleaf weed control in spring-transplanted onions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Controlling weeds can be a costly and time consuming process and uncontrolled weeds can reduce or eliminate crop yields and profits. In conventional agriculture, the use of herbicides provides a valuable tool within an integrated weed control system, but there are very few organically approved her...

  3. Weed management in transplanted lettuce with Pendimethalin and S-metolachlor

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Few herbicides are available for use in lettuce and hand weeding is required for commercially acceptable weed control. More effective herbicides are needed. Here we report field evaluations of pendimethalin and S-metolachlor for weed control in transplanted lettuce. Pendimethalin was evaluated PRE a...

  4. Improving weed germination models by incorporating seed microclimate and translocation by tillage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed emergence models are of critical importance in deciding the timing of field weed control measures (tillage or chemical). However, the state of weed germination modeling is still in its infancy. Existing models do provide a baseline picture of emergence patterns, but improvements are needed to m...

  5. 7 CFR 201.17 - Noxious-weed seeds in the District of Columbia.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Noxious-weed seeds in the District of Columbia. 201.17... ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.17 Noxious-weed seeds in the District of Columbia. (a) Noxious-weed seeds in the District of Columbia are: Quackgrass (Elytrigia...

  6. 7 CFR 360.500 - Petitions to add a taxon to the noxious weed list.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 5 2013-01-01 2013-01-01 false Petitions to add a taxon to the noxious weed list. 360... PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.500 Petitions to add a taxon to the noxious weed list. A person may petition the Administrator to have a...

  7. 7 CFR 360.302 - Consideration of applications for permits to move noxious weeds.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... noxious weeds. 360.302 Section 360.302 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.302 Consideration of applications for permits to move noxious weeds. Upon the receipt of an application made...

  8. 7 CFR 201.65 - Noxious weed seeds in interstate commerce.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Noxious weed seeds in interstate commerce. 201.65... ACT FEDERAL SEED ACT REGULATIONS Tolerances § 201.65 Noxious weed seeds in interstate commerce. Tolerances for rates of occurrence of noxious-weed seeds shall be recognized and shall be applied to...

  9. 7 CFR 360.300 - General prohibitions and restrictions on the movement of noxious weeds; permits.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... of noxious weeds; permits. 360.300 Section 360.300 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.300 General prohibitions and restrictions on the movement of noxious weeds; permits. (a)...

  10. 7 CFR 360.500 - Petitions to add a taxon to the noxious weed list.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 5 2012-01-01 2012-01-01 false Petitions to add a taxon to the noxious weed list. 360... PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.500 Petitions to add a taxon to the noxious weed list. A person may petition the Administrator to have a...

  11. 7 CFR 360.500 - Petitions to add a taxon to the noxious weed list.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 5 2014-01-01 2014-01-01 false Petitions to add a taxon to the noxious weed list. 360... PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.500 Petitions to add a taxon to the noxious weed list. A person may petition the Administrator to have a...

  12. 7 CFR 360.501 - Petitions to remove a taxon from the noxious weed lists.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 5 2013-01-01 2013-01-01 false Petitions to remove a taxon from the noxious weed...) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.501 Petitions to remove a taxon from the noxious weed lists. A person may petition the Administrator to remove...

  13. 7 CFR 201.65 - Noxious weed seeds in interstate commerce.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Noxious weed seeds in interstate commerce. 201.65... ACT FEDERAL SEED ACT REGULATIONS Tolerances § 201.65 Noxious weed seeds in interstate commerce. Tolerances for rates of occurrence of noxious-weed seeds shall be recognized and shall be applied to...

  14. 7 CFR 360.302 - Consideration of applications for permits to move noxious weeds.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... noxious weeds. 360.302 Section 360.302 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.302 Consideration of applications for permits to move noxious weeds. Upon the receipt of an application made...

  15. 7 CFR 360.301 - Information required for applications for permits to move noxious weeds.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... move noxious weeds. 360.301 Section 360.301 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.301 Information required for applications for permits to move noxious weeds. (a) Permit to...

  16. 7 CFR 360.301 - Information required for applications for permits to move noxious weeds.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... move noxious weeds. 360.301 Section 360.301 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.301 Information required for applications for permits to move noxious weeds. (a) Permit to...

  17. 7 CFR 360.301 - Information required for applications for permits to move noxious weeds.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... move noxious weeds. 360.301 Section 360.301 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.301 Information required for applications for permits to move noxious weeds. (a) Permit to...

  18. 7 CFR 360.501 - Petitions to remove a taxon from the noxious weed lists.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 5 2012-01-01 2012-01-01 false Petitions to remove a taxon from the noxious weed...) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.501 Petitions to remove a taxon from the noxious weed lists. A person may petition the Administrator to remove...

  19. 7 CFR 201.17 - Noxious-weed seeds in the District of Columbia.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Noxious-weed seeds in the District of Columbia. 201.17... ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.17 Noxious-weed seeds in the District of Columbia. (a) Noxious-weed seeds in the District of Columbia are: Quackgrass (Elytrigia...

  20. 7 CFR 360.501 - Petitions to remove a taxon from the noxious weed lists.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 5 2014-01-01 2014-01-01 false Petitions to remove a taxon from the noxious weed...) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.501 Petitions to remove a taxon from the noxious weed lists. A person may petition the Administrator to remove...

  1. 7 CFR 360.302 - Consideration of applications for permits to move noxious weeds.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... noxious weeds. 360.302 Section 360.302 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.302 Consideration of applications for permits to move noxious weeds. Upon the receipt of an application made...

  2. 7 CFR 201.17 - Noxious-weed seeds in the District of Columbia.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 3 2012-01-01 2012-01-01 false Noxious-weed seeds in the District of Columbia. 201.17... ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.17 Noxious-weed seeds in the District of Columbia. (a) Noxious-weed seeds in the District of Columbia are: Quackgrass (Elytrigia...

  3. 7 CFR 201.17 - Noxious-weed seeds in the District of Columbia.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 3 2014-01-01 2014-01-01 false Noxious-weed seeds in the District of Columbia. 201.17... ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.17 Noxious-weed seeds in the District of Columbia. (a) Noxious-weed seeds in the District of Columbia are: Quackgrass (Elytrigia...

  4. 7 CFR 201.17 - Noxious-weed seeds in the District of Columbia.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 false Noxious-weed seeds in the District of Columbia. 201.17... ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.17 Noxious-weed seeds in the District of Columbia. (a) Noxious-weed seeds in the District of Columbia are: Quackgrass (Elytrigia...

  5. 7 CFR 360.501 - Petitions to remove a taxon from the noxious weed lists.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 5 2011-01-01 2011-01-01 false Petitions to remove a taxon from the noxious weed...) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.501 Petitions to remove a taxon from the noxious weed lists. A person may petition the Administrator to remove...

  6. 7 CFR 360.302 - Consideration of applications for permits to move noxious weeds.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... noxious weeds. 360.302 Section 360.302 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.302 Consideration of applications for permits to move noxious weeds. Upon the receipt of an application made...

  7. 7 CFR 360.301 - Information required for applications for permits to move noxious weeds.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... move noxious weeds. 360.301 Section 360.301 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.301 Information required for applications for permits to move noxious weeds. (a) Permit to...

  8. 7 CFR 360.500 - Petitions to add a taxon to the noxious weed list.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 5 2011-01-01 2011-01-01 false Petitions to add a taxon to the noxious weed list. 360... PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.500 Petitions to add a taxon to the noxious weed list. A person may petition the Administrator to have a...

  9. Lawn Weed Control with Herbicides. Home and Garden Bulletin No. 123.

    ERIC Educational Resources Information Center

    Agricultural Research Service (USDA), Washington, DC.

    Information and diagrams are given for identification and treatment of weed grasses and broadleaf weeds. Herbicides are suggested for use against each weed and instructions are given for proper application. Information is given for buying herbicides, and applying sprays and cleaning sprayers. (BB)

  10. Airborne hyperspectral and LiDAR data integration for weed detection

    NASA Astrophysics Data System (ADS)

    Tamás, János; Lehoczky, Éva; Fehér, János; Fórián, Tünde; Nagy, Attila; Bozsik, Éva; Gálya, Bernadett; Riczu, Péter

    2014-05-01

    Agriculture uses 70% of global available fresh water. However, ca. 50-70% of water used by cultivated plants, the rest of water transpirated by the weeds. Thus, to define the distribution of weeds is very important in precision agriculture and horticulture as well. To survey weeds on larger fields by traditional methods is often time consuming. Remote sensing instruments are useful to detect weeds in larger area. In our investigation a 3D airborne laser scanner (RIEGL LMS-Q680i) was used in agricultural field near Sopron to scouting weeds. Beside the airborne LiDAR, hyperspectral imaging system (AISA DUAL) and air photos helped to investigate weed coverage. The LiDAR survey was carried out at early April, 2012, before sprouting of cultivated plants. Thus, there could be detected emerging of weeds and direction of cultivation. However airborne LiDAR system was ideal to detect weeds, identification of weeds at species level was infeasible. Higher point density LiDAR - Terrestrial laser scanning - systems are appropriate to distinguish weed species. Based on the results, laser scanner is an effective tool to scouting of weeds. Appropriate weed detection and mapping systems could contribute to elaborate water and herbicide saving management technique. This publication was supported by the OTKA project K 105789.

  11. Predicting field weed emergence with empirical models and soft computing techniques

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seedling emergence is the most important phenological process that influences the success of weed species; therefore, predicting weed emergence timing plays a critical role in scheduling weed management measures. Important efforts have been made in the attempt to develop models to predict seedling e...

  12. VINEYARD WEED SEEDBANK COMPOSITION RESPONDS TO GLYPHOSATE AND CULTIVATION AFTER THREE YEARS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Herbicide and tillage have been shown to influence weed seedbank composition in annual cropping systems, but little information is available for perennial cropping systems like vineyards, where weed control practices are comparatively less intensive. We hypothesized that vineyard weed seedbanks woul...

  13. Beyond Patch Spraying: Site-specific Weed Mmanagement With Multiple Herbicides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Site-specific weed management can include both limiting herbicide to areas of the field where weed pressure is above the economic threshold (patch spraying) and varying the choice of herbicide for most cost-effective weed control of local populations. The benefits of patch spraying with multiple, po...

  14. Seed Production as Influenced by Glyphosate Applications Across a Weed Community

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Late-season weed infestations often do not affect yields and are allowed to mature and contribute seed to the soil seedbank, ensuring the future establishment of competitive weed communities. Effective long-term weed management strategies must incorporate practices to reduce the soil seedbank by re...

  15. Integrating multiple tactics for managing weeds in high residue no-till soybean

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rolled cover crop mulches can suppress weeds in subsequent cash crops, reduce the need for herbicides and allow organic no-till cash crop establishment. This study investigated the weed suppressiveness of a cereal rye (Secale cereale L.) cover crop mulch across varying weed seedbank density. Cereal ...

  16. Weed management practices for organic production of trailing blackberry. I. Plant growth and early fruit production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed management practices were evaluated in a new field of trailing blackberry established in western Oregon. The field was planted in May 2010 and certified organic in May 2012. Treatments included two cultivars, ‘Marion’ and ‘Black Diamond’, grown in 1) non-weeded plots, where weeds were cut to th...

  17. Residual Weeds of Processing Sweet Corn in the North Central Region

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Knowledge of weed community structure in vegetable crops of the North Central Region (NCR) is poor. To characterize weed composition of species persisting in sweet corn to harvest, hereafter called residual weeds, 175 sweet corn fields were surveyed in Illinois, Minnesota, and Wisconsin from 2005 to...

  18. Image classification approach for automatic identification of grassland weeds

    NASA Astrophysics Data System (ADS)

    Gebhardt, Steffen; Kühbauch, Walter

    2006-08-01

    The potential of digital image processing for weed mapping in arable crops has widely been investigated in the last decades. In grassland farming these techniques are rarely applied so far. The project presented here focuses on the automatic identification of one of the most invasive and persistent grassland weed species, the broad-leaved dock (Rumex obtusifolius L.) in complex mixtures of grass and herbs. A total of 108 RGB-images were acquired in near range from a field experiment under constant illumination conditions using a commercial digital camera. The objects of interest were separated from the background by transforming the 24 bit RGB-images into 8 bit intensities and then calculating the local homogeneity images. These images were binarised by applying a dynamic grey value threshold. Finally, morphological opening was applied to the binary images. The remaining contiguous regions were considered to be objects. In order to classify these objects into 3 different weed species, a soil and a residue class, a total of 17 object-features related to shape, color and texture of the weeds were extracted. Using MANOVA, 12 of them were identified which contribute to classification. Maximum-likelihood classification was conducted to discriminate the weed species. The total classification rate across all classes ranged from 76 % to 83 %. The classification of Rumex obtusifolius achieved detection rates between 85 % and 93 % by misclassifications below 10 %. Further, Rumex obtusifolius distribution and the density maps were generated based on classification results and transformation of image coordinates into Gauss-Krueger system. These promising results show the high potential of image analysis for weed mapping in grassland and the implementation of site-specific herbicide spraying.

  19. [Lead absorption by weeds from lead-polluted soil].

    PubMed

    Wu, Chunhua; Chen, Xin; Wang, Zhaoqian

    2004-08-01

    A pot experiment with red soil was installed in 2002 and 2003 to study the impact of lead pollution on weed growth, its lead and nutrients uptake, and AMF colonization. The results showed that lead pollution had no significant influence on weed growth, and the absorbed lead was mainly accumulated in root system. The impact of lead pollution on nutrients uptake by weeds was depended on weed species, their growth stages, and kinds of nutrients. No significant difference was found between lead treatment and control in nutrient contents except potassium in Digitaria adscendens at its early growth stages, and lead had little influence on the absorption of nutrients by Kummerowia striata, Ixeris chinensis, Digitaria adscendens and Echinochloa crusgalli var. mitis. The phosphorus content in Ixeris chinensis and Digitaria adscendens at their ripen stage sampled from lead-polluted soil was significantly higher than that from control, while the nitrogen content in matured Echinochloa crusgalli var. mitis sampled from polluted soil was significantly lower than that from the control. There existed great difference of mycorrhizal colonization among various weed species. The infection rate of Kummerowia striata and Digitaria adscendens showed a slight difference between lead treatment and control both at vegetative and ripen stage. Lead pollution hindered the colonization of Ixeris chinensis. In lead-polluted soil, the AMF infection rate of Ixeris chinensis was 45.52% at vegetative stage and 74.64% at ripen stage, while in the control, it was 69.44% at vegetative stage and 82.21% at ripen stage. Echinochloa crusgalli var. mitis, an annual weed, showed an opposite response of AMF colonization to lead pollution. The colonization rate of AMF in Echinochloa crusgalii var. mitis root was higher under lead pollution condition, being 82.45% at vegetative stage and 91.36% at ripen stage, while in the control, it was 59.19% and 78.28%, respectively. PMID:15574006

  20. Phenological observations on shrubs to predict weed emergence in turf

    NASA Astrophysics Data System (ADS)

    Masin, Roberta; Zuin, Maria Clara; Zanin, Giuseppe

    2005-09-01

    Phenology is the study of periodic biological events. If we can find easily recognizable events in common plants that precede or coincide with weed emergences, these plants could be used as indicators. Weed seedlings are usually difficult to detect in turf, so the use of phenological indicators may provide an alternative approach to predict the time when a weed appears and consequently guide management decisions. A study was undertaken to determine whether the phenological phases of some plants could serve as reliable indicators of time of weed emergence in turf. The phenology of six shrubs (Crataegus monogyna Jacq., Forsythia viridissima Lindl., Sambucus nigra L., Syringa vulgaris L., Rosa multiflora Thunb., Ziziphus jujuba Miller) and a perennial herbaceous plant [Cynodon dactylon (L.) Pers.] was observed and the emergence dynamics of four annual weed species [Digitaria sanguinalis (L.) Scop., Eleusine indica (L.) Gaertner, Setaria glauca (L.) Beauv., Setaria viridis (L.) Beauv.] were studied from 1999 to 2004 in northern Italy. A correlation between certain events and weed emergence was verified. S. vulgaris and F. viridissima appear to be the best indicators: there is a quite close correspondence between the appearance of D. sanguinalis and lilac flowering and between the beginning of emergence of E. indica and the end of lilac flowering; emergences of S. glauca and S. viridis were predicted well in relation to the end of forsythia flowering. Base temperatures and starting dates required to calculate the heat unit sums to reach and complete the flowering phase of the indicators were calculated using two different methods and the resultant cumulative growing degree days were compared.

  1. Development of a spatial method for weed detection and localization

    NASA Astrophysics Data System (ADS)

    Vioix, Jean-Baptiste; Douzals, Jean-Paul; Truchetet, Fréd. éric

    2004-02-01

    This paper presents an algorithm specifically developed for filtering low frequency signals. The application is related to weed detection into aerial images where crop lines are detected as repetitive structures. Theoretical bases of this work are presented first. Then, two methods are compared to select low frequency signals and their limitations are described. A decomposition based on wavelet packet is used to combine advantages of both methods. This algorithm allows a high selectivity of low frequency signals with an interesting computation time. At last, a complete algorithm for weed/crop classification is explained and a few results are shown.

  2. Study on the weed-crop competition for nutrients in maize.

    PubMed

    Lehoczky, E; Reisinger, P

    2003-01-01

    Considering the effect of crop-weed competition the rate of weed growing, the competitiveness of the occurring weed species and the duration of competition are determining factors. Experiments were carried out on fields in order to collect data on the effect of early weed competition on maize, including the competition for nutrients and the possible rate of nutrient removal by weeds. From 7 sampling areas of the 9.2 ha field weeds and maize samples were collected 1 month after the sowing of maize. We determined the total numbers and the species numbers of weeds by plots. The removed plant species and maize were weighed then dried until the weight balance was reached. The samples were tested for N, P, K and Ca. Comparison was done with the weight and nutrient element content of maize plants taken from the treated, weed-free area. At the same time comparative analyses were made with the mass and nutrient contents of maize plants. There were 12 occurring weed species in this experiment. Based on the rate of weed cover the following species were dominant: Datum stramonium L., Cannabis sativa L., Amaranthus chlorostachis Willd., Chenopodium album L., Chenopodium hybridum L. Our experiments revealed that in the areas being likely to produce high weed populations and showing a considerable high nutrient removal by weeds, the competition between weed plants and maize occurs at an earlier stage of the vegetation period of maize than on fields with moderate weed populations. Weeds have utilised significant amount of nutrients which has been many fold of maize in case of unit area. PMID:15149132

  3. Seed preferences by rodents in the agri-environment and implications for biological weed control.

    PubMed

    Fischer, Christina; Türke, Manfred

    2016-08-01

    Post-dispersal seed predation and endozoochorous seed dispersal are two antagonistic processes in relation to plant recruitment, but rely on similar preconditions such as feeding behavior of seed consumers and seed traits. In agricultural landscapes, rodents are considered important seed predators, thereby potentially providing regulating ecosystem services in terms of biological weed control. However, their potential to disperse seeds endozoochorously is largely unknown. We exposed seeds of arable plant species with different seed traits (seed weight, nutrient content) and different Red List status in an experimental rye field and assessed seed removal by rodents. In a complementary laboratory experiment, consumption rates, feeding preferences, and potential endozoochory by two vole species (Microtus arvalis and Myodes glareolus) were tested. Seed consumption by rodents after 24 h was 35% in the field and 90% in the laboratory. Both vole species preferred nutrient-rich over nutrient-poor seeds and M. glareolus further preferred light over heavy seeds and seeds of common over those of endangered plants. Endozoochory by voles could be neglected for all tested plant species as no seeds germinated, and only few intact seeds could be retrieved from feces. Synthesis and applications. Our results suggest that voles can provide regulating services in agricultural landscapes by depleting the seed shadow of weeds, rather than facilitating plant recruitment by endozoochory. In the laboratory, endangered arable plants were less preferred by voles than noxious weeds, and thus, our results provide implications for seed choice in restoration approaches. However, other factors such as seed and predator densities need to be taken into account to reliably predict the impact of rodents on the seed fate of arable plants. PMID:27547355

  4. Combinations of corn glutel meal, clove oil, and sweep cultivation are ineffective for weed control in organic peanut production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed control in organic peanut is difficult and lack of residual weed control complicates weed management efforts. Weed management systems using corn gluten meal in combination with clove oil and sweep cultivation were evaluated in a series of irrigated field trials. Corn gluten meal applied in a ...

  5. Modeling "habitat suitability" for a herbicide resistant weed using a species distribution model and presence-only data

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Herbicide resistant weeds are like invasive weeds: prompt management is needed to prevent their spread. For invasive weeds, first reports of a weed's occurrence are often analyzed with species distribution models (SDM) to prioritize detection and treatment. Suitability of other areas as habitat for ...

  6. Weed management, training, and irrigation practices for organic production of trailing blackberry: II. Soil and plant nutrient concentrations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic production of blackberries is increasing, but there is relatively little known about how production practices affect plant and soil nutrient status. The impact of cultivar (‘Black Diamond’ and ‘Marion’), weed management (weed mat, hand weeding, and no weeding), primocane training time (Augus...

  7. Weed management, training, and irrigation practices for organic production of trailing blackberry: II. Soil and plant nutrient concentrations.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic production of blackberries is increasing, but there is relatively little known about how production practices affect plant and soil nutrient status. The impact of cultivar (‘Black Diamond’ and ‘Marion’), weed management (weed mat, hand weeding, and no weeding), primocane training time (Augus...

  8. Herbicide-Resistant Crops: Utilities and Limitations for Herbicide-Resistant Weed Management

    PubMed Central

    2010-01-01

    Since 1996, genetically modified herbicide-resistant (HR) crops, particularly glyphosate-resistant (GR) crops, have transformed the tactics that corn, soybean, and cotton growers use to manage weeds. The use of GR crops continues to grow, but weeds are adapting to the common practice of using only glyphosate to control weeds. Growers using only a single mode of action to manage weeds need to change to a more diverse array of herbicidal, mechanical, and cultural practices to maintain the effectiveness of glyphosate. Unfortunately, the introduction of GR crops and the high initial efficacy of glyphosate often lead to a decline in the use of other herbicide options and less investment by industry to discover new herbicide active ingredients. With some exceptions, most growers can still manage their weed problems with currently available selective and HR crop-enabled herbicides. However, current crop management systems are in jeopardy given the pace at which weed populations are evolving glyphosate resistance. New HR crop technologies will expand the utility of currently available herbicides and enable new interim solutions for growers to manage HR weeds, but will not replace the long-term need to diversify weed management tactics and discover herbicides with new modes of action. This paper reviews the strengths and weaknesses of anticipated weed management options and the best management practices that growers need to implement in HR crops to maximize the long-term benefits of current technologies and reduce weed shifts to difficult-to-control and HR weeds. PMID:20586458

  9. Simulation of agronomic images for an automatic evaluation of crop/ weed discrimination algorithm accuracy

    NASA Astrophysics Data System (ADS)

    Jones, G.; Gée, Ch.; Truchetet, F.

    2007-01-01

    In the context of precision agriculture, we present a robust and automatic method based on simulated images for evaluating the efficiency of any crop/weed discrimination algorithms for a inter-row weed infestation rate. To simulate these images two different steps are required: 1) modeling of a crop field from the spatial distribution of plants (crop and weed) 2) projection of the created field through an optical system to simulate photographing. Then an application is proposed investigating the accuracy and robustness of crop/weed discrimination algorithm combining a line detection (Hough transform) and a plant discrimination (crop and weeds). The accuracy of weed infestation rate estimate for each image is calculated by direct comparison to the initial weed infestation rate of the simulated images. It reveals an performance better than 85%.

  10. Host Status of Seven Weed Species and Their Effects on Ditylenchus destructor Infestation of Peanut

    PubMed Central

    De Waele, D.; Jordaan, Elizabeth M.; Basson, Selmaré

    1990-01-01

    The host suitability to Ditylenchus destructor of seven common weed species in peanut (Arachis hypogaea) fields in South Africa was determined. Based on the number of nematodes per root unit, white goosefoot (Chenopodium album), feathertop chloris (Chloris virgata), purple nutsedge (Cyperus rotundus), jimson weed (Datura stramonium), goose grass (Eleusine indica), khaki weed (Tagetes minuta), and cocklebur (Xanthium strumarium) were poor hosts. Ditylenchus destructor survived on all weed species; population densities increased in peanut hulls and caused severe damage to seeds of peanut grown after weeds. Roots of purple nutsedge left in the soil suppressed populations of D. destructor and root and pod development in peanut grown after the weed. However, nematode populations in peanut hulls and seeds were not suppressed. Some weed species, especially purple nutsedge which is common in peanut fields, can be used to indicate the presence of D. destructor in the absence of peanut. PMID:19287723

  11. Host Status of Seven Weed Species and Their Effects on Ditylenchus destructor Infestation of Peanut.

    PubMed

    De Waele, D; Jordaan, E M; Basson, S

    1990-07-01

    The host suitability to Ditylenchus destructor of seven common weed species in peanut (Arachis hypogaea) fields in South Africa was determined. Based on the number of nematodes per root unit, white goosefoot (Chenopodium album), feathertop chloris (Chloris virgata), purple nutsedge (Cyperus rotundus), jimson weed (Datura stramonium), goose grass (Eleusine indica), khaki weed (Tagetes minuta), and cocklebur (Xanthium strumarium) were poor hosts. Ditylenchus destructor survived on all weed species; population densities increased in peanut hulls and caused severe damage to seeds of peanut grown after weeds. Roots of purple nutsedge left in the soil suppressed populations of D. destructor and root and pod development in peanut grown after the weed. However, nematode populations in peanut hulls and seeds were not suppressed. Some weed species, especially purple nutsedge which is common in peanut fields, can be used to indicate the presence of D. destructor in the absence of peanut. PMID:19287723

  12. [Potential role of winter rape weeds in the extension of broomrape in Poitou-Charentes].

    PubMed

    Gibot-Leclerc, Stéphanie; Brault, Marianne; Pinochet, Xavier; Sallé, Georges

    2003-07-01

    In the Poitou-Charentes district, among the 82 species of winter rape weeds identified, 22 displayed a strong affinity for this crop (Brassica napus L.). In fields, 50% of these weeds were parasitized by Orobanche ramosa, playing the role of host plants. Greenhouse co-cultures (weed/Orobanche ramosa) showed that weeds non-parasitized in fields could be attacked by broomrape, developing a more or less complete cycle. In vitro co-cultures (weed/Orobanche ramosa) revealed that root exudates of non-parasitized weeds, in fields or in greenhouse co-cultures, could induce Orobanche ramosa seed germination, but not attachment. These weeds could play the role of false hosts. PMID:14556384

  13. Response of four sweet corn hybrids to weed management level.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Planting no-till into cover crop residues left on the soil surface offers benefits of suppressing weeds, reducing soil erosion, and eliminating trips through the field. Adequate suppression of cover crops to prevent competition with the main crop can be challenging, particularly in organic systems w...

  14. A new weed control strategy in onion culture.

    PubMed

    Thieron, M; Kerres, W; Schäffer, A

    2007-01-01

    A new strategy combining modem hoeing technique and spray application has been developed in order to reduce the amount of herbicides down to 20% compared to common practice. The effects on weed control have been investigated as well as the impact on qualitative and quantitative harvest. In two large scale field trials and two years of testing the authors evaluated different hoeing techniques combined with band spray application and standard spray application, the minimal lethal herbicide dose method (MLHD). All varieties have been calculated for environmental impact as well as practical and economical means. These studies reveal crop losses due to improper weed control as well as losses due to herbicide stress. Detailed information on concentration depending impact of several herbicides have been correlated to their control of different weeds and the achieved yield. Two contrary effects influencing the total yield have been identified. The novel strategy is based on the knowledge of these complex effects which finally led to a well practicable and highly economic strategy that enables onion farmers to control weeds while reducing the amounts of herbicides down to approximately 20%. PMID:18399447

  15. STRATEGIES FOR THE USE OF NATURAL PRODUCTS FOR WEED MANAGEMENT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Natural products have not been utilized as extensively for weed management as they have been for insect and plant pathogen management, but there are several notable successes such as glufosinate and the natural product-derived triketone herbicides. The two fundamental approaches to the use of natur...

  16. Organic weed control for cantaloupe methods comparison trial

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Effective weed control is needed for successful melon production. Synthetic herbicides that are available for non-organic melon production cannot be used in organic production. In addition to organic producers' needs, herbicide use is not always practical in many garden situations, whether organic o...

  17. Effect of intermittent irrigation on rice productivity and weed suppression

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Certain indica rice lines from Asia have been shown to suppress barnyardgrass (Echinochloa crus-galli) effectively in conventional flood-irrigated (FLI) production systems, but their weed suppression potential in “intermittent flood-irrigated” (IFI) production systems is unknown. IFI systems (aka “...

  18. Laser-induced fluorescence for discrimination of crops and weeds

    NASA Astrophysics Data System (ADS)

    Hilton, Peter J.

    2000-11-01

    This paper reports the use of Laser Induced Fluorescence (LIF) of plants to discriminate between crops and weeds for potential use in an intelligent crop spraying system. Past and current work in intelligent crop spraying has concentrated on using multi-spectral reflectance data in particular using near infrared (NIR) and color. Texture and shape image processing has also been used with limited success and is usually computationally expensive. Also, most of these approaches are error prone since they rely on ambient solar illumination and so are susceptible to errors caused by cloud variations, shadows and other non-uniformities. There are several commercial spraying systems available that detect presence or absence of plants using the NIR 'red-edge' effect without discrimination between species. 'Weedseeker' and 'Detectspray' are two examples of such systems, the 'Weedseeker' system being one of the few active systems, incorporating its own light source. However, both systems suffer from poor spatial resolution. The use of plant or chlorophyll fluorescence for discrimination between species is a relatively under researched area. This paper shows that LIF of several crops and weeds can be used to discriminate between species. Spectra are presented for two crop and two weed species over a range of discrete laser excitation wavelengths. The technique can be directly implemented with a laser imaging system for real-time detection and discrimination of crops and weeds.

  19. Real-time weed detection in outdoor field conditions

    NASA Astrophysics Data System (ADS)

    Steward, Brian L.; Tian, Lei F.

    1999-01-01

    Though most herbicide is applied uniformly in agronomic fields, there is strong evidence that weeds are not distributed uniformly within the crop fields. If an effective weed detection system were developed, both economic and environmental benefits would result from its use for site-specific weed management. Past work in this area has focused mainly on either low spatial resolution photo-detectors or off-line machine vision system. This study was undertaken to develop real-time machine vision weed detection for outdoor lighting conditions. The novel environmentally adaptive segmentation algorithm was developed with the objective of real-time operation on an on-board computer-based system. The EASA used cluster analysis to group pixels of homogeneous color regions of the image together which formed the basis for image segmentation. The performance of several variations of this algorithm was measured by comparing segmented field images produced by the EASA, fixed-color HSI region segmentation, and ISODATA clustering with hand-=segmented reference images. The time cost and questionable accuracy of hand- segmented reference images led to exploration of the use of computer-segmented reference images. Sensitivity and background sensitivity were used as performance measured. Significant differences were found between the means of sensitivity, background sensitivity, and overall performance across segmentation schemes. Similar results were obtained with computer-segmented reference images.

  20. Biology and Biological Control of Mile-a-Minute Weed

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mile-a-minute weed (MAM), Persicaria perfoliata (L.) H. Gross (Fig. 1), is a member of the family Polygonaceae. It is an annual vine that can grow up to 6 meters long over the course of a season. It is widely distributed throughout east Asia, including Japan, China, Korea, India, Indonesia, Banglade...

  1. 7 CFR 201.52 - Noxious-weed seeds.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ..., Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT... following indicated numbers of a single kind of seed, bulblet, or tuber are found in the pure seed analysis (or noxious-weed seed examination of a like amount) the occurrence of that kind in the remainder...

  2. 7 CFR 201.52 - Noxious-weed seeds.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ..., Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT... following indicated numbers of a single kind of seed, bulblet, or tuber are found in the pure seed analysis (or noxious-weed seed examination of a like amount) the occurrence of that kind in the remainder...

  3. 7 CFR 201.52 - Noxious-weed seeds.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ..., Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT... following indicated numbers of a single kind of seed, bulblet, or tuber are found in the pure seed analysis (or noxious-weed seed examination of a like amount) the occurrence of that kind in the remainder...

  4. 7 CFR 201.52 - Noxious-weed seeds.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ..., Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT... following indicated numbers of a single kind of seed, bulblet, or tuber are found in the pure seed analysis (or noxious-weed seed examination of a like amount) the occurrence of that kind in the remainder...

  5. 7 CFR 201.52 - Noxious-weed seeds.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ..., Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT... following indicated numbers of a single kind of seed, bulblet, or tuber are found in the pure seed analysis (or noxious-weed seed examination of a like amount) the occurrence of that kind in the remainder...

  6. Confused about Fusion? Weed Your Science Collection with a Pro.

    ERIC Educational Resources Information Center

    O'Dell, Charli

    1998-01-01

    Provides guidelines on weeding science collections in junior high/high school libraries. Highlights include checking copyright dates, online sources, 13 science subject areas that deserve special consideration (plate tectonics, fission, fusion, radioactive dating, weather/climate, astronomy/space science, elements, integrated science,…

  7. Vinegar: Application volumes and adjuvants for weed control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vinegar has been identified as a potential organic herbicide, yet more information is needed to determine influence of application volume and use of additives (adjuvants) on weed control. Vinegar is a solution containing water and acetic acid, an organic acid produced through the natural fermentatio...

  8. Integrated Systems of Weed Management in Organic 'Vidalia' Onion

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Trials were conducted in southeastern Georgia to develop integrated systems of weed management in organic Vidalia® onion. Treatments were a factorial arrangement of summer solarization, cultivation, and herbicides appropriate for use in certified organic production systems. Plots were solarized wi...

  9. Weed control and canopy light management in blackberries

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed control in blackberries (Rubus spp.) is a serious problem for organic producers and those who wish to reduce their reliance on herbicides. At the southern limits of blackberry production, late season yields are reduced because of high day-time temperatures generated by solar irradiation and ot...

  10. Managing weeds with a population-based approach

    Technology Transfer Automated Retrieval System (TEKTRAN)

    No-till cropping systems are improving precipitation-use-efficiency, increasing land productivity, and restoring soil health in semiarid regions of the world. However, weed resistance, rising costs, and concern about environmental impacts are stimulating questions about the extensive reliance on he...

  11. Potential of Air-Propelled Abrasives for Selective Weed Control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Novel forms of selective weed control are needed by many types of growers, but especially organic growers who are restricted from using synthetic herbicides. Abrasive grit made from corn cobs was expelled from a sand blaster at 517 kPa pressure and aimed at seedlings of common lambsquarters and corn...

  12. Onion and weed response to mustard (Sinapis alba) seed meal

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Onion and weed response to mustard seed meal (MSM) were tested in greenhouse and field trials in 2007-2009. MSM was applied to the soil surface at rates of 1.1, 2.2, and 4.4 MT/ha. In greenhouse trials, onions were severely injured and stands reduced with all rates of MSM applied prior to onion emer...

  13. Weed Community and Glyphosate Management in Soybean Crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A concern to some conservationists is the loss of biodiversity of weedy plant species in the face of wide-spread adoption by farmers of transgenic crops that are resistant to broad-spectrum herbicides such as glyphosate. We studied weed biodiversity in both Argentina and the USA, the two countries w...

  14. 75 FR 68945 - Update of Noxious Weed Regulations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-10

    ... (74 FR 27456-27467, Docket No. APHIS-2007-0146) a proposal \\1\\ to make several changes to the... interim rule published and effective on October 19, 2009 (74 FR 53397-53400, Docket No. APHIS-2008-0097... contaminated with various noxious weed seeds, including Cuscuta spp. We have determined that heat...

  15. Crop seeding level: implications for weed management in sweet corn

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sweet corn is seeded under a wide range of population densities; however, the extent to which variable population density influences weed fitness is unknown. Therefore, field studies were undertaken to quantify the influence of sweet corn seeding level on growth, seed production, and post-harvest se...

  16. Robust crop and weed segmentation under uncontrolled outdoor illumination

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A new machine vision for weed detection was developed from RGB color model images. Processes included in the algorithm for the detection were excessive green conversion, threshold value computation by statistical analysis, adaptive image segmentation by adjusting the threshold value, median filter, ...

  17. Response of `Alamo` switchgrass (Panicum virgatum) to weed management practices

    SciTech Connect

    Sledge, S.L.; Walker, R.H.

    1995-11-01

    Field studies were conducted in 1992 and 1994 to evaluate herbicides that would provide weed control and biomass yield of `Alamo` switchgrass during the year of establishment. For grass weed control, bensulide was applied preplant incorporated (PPI) at 4.4 kg ai ha{sup -1}, while MSMA was applied postemergence over the top (POST) at 2.2 kg ai ha{sup -1} to switchgrass that had two to four leaves. Herbicides applied POST for control of broadleaf weed species included 2,4-D at 0.6 kg ai ha{sup -1} or metsulfuron at 0.02 kg ai ha{sup -1}. Herbicide treatments included bensulide and MSMA applied alone or in combination with s,3-D or metsulfuron. They were arranged in a randomized complete block design and replicated four times. Weed control, crop tolerance and yield data were taken over time. Bensulide or MSMA applied alone provided 80% or greater control of large crabgrass, broadleaf signalgrass and fall panicum for the two years. The addition of metsulfuron or 2,4-D provided acceptable control of smooth pigweed, prickly sida, pitted morningglory and sicklepod. MSMA treatments produced slight PANVI injury that ranged from 20 to 36%. Bensulide injury was mostly moderate ranging from 19 to 88%. Although less injury was recorded with MSMA treatments, bensulide treatments trended higher for establishment-year biomass production that averaged 5123 kg ha{sup -1} as compared to 4239 kg ha{sup -1} for MSMA treatments.

  18. Effectiveness of Eriophyid Mites for Biological Control of Weeds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Eriophyid mites are thought to have a high potential for use as classical biological control agents of weeds. However, in the past 20 years few species have been authorized for introduction, and few have significantly reduced the target plant's population. Natural enemies, resistant plant genotype...

  19. Alternatives to atrazine for weed management in processing sweet corn

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Atrazine has been the most widely used herbicide in North American processing sweet corn for decades; however, increased restrictions in recent years have reduced or eliminated atrazine use in certain production areas. The objective of this study was to identify the best stakeholder-derived weed man...

  20. Herbicide Leaching Column for a Weed Science Teaching Laboratory.

    ERIC Educational Resources Information Center

    Ahrens, W. H.

    1986-01-01

    Presents an experiment which enables weed science students to observe first-hand the process of herbicide leaching in soils. Features of this technique which demonstrate the movement of herbicide within a column of soil are outlined. Diagrams are provided of the apparatus employed in the exercise. (ML)

  1. Cover crop and organic weed control integration in tomato

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The increased adoption of conservation tillage in organic vegetable production requires more information on the role of various cover crops in weed control, tomato quality and yield. An experiment was established in autumn 2005 and 2006 at the North Alabama Horticulture Experiment Station, Cullman,...

  2. Revegetation Guidelines for the Great Basin: Considering Invasive Weeds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Large portions of the Great Basin become degraded and disturbed every day due to natural and human-induced causes. Some disturbed areas may recover naturally in time, but other areas may never recover naturally because invasive weeds establish quickly and prevent native plants from establishing. I...

  3. An application of soft sets in weed identification

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soft set theory is originally proposed as a general mathematical tool for dealing with uncertainties present in most of our real life. This study applied soft sets to improve low accuracy of weed identification caused by similar features. Firstly, three types of plant leaf features including shape, ...

  4. COVER CROP SYSTEMS AFFECT WEED COMMUNITIES IN A CALIFORNIA VINEYARD

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vineyard weed communities were examined under four dormant season cover crop systems representative of those used in the north-coastal grape-growing region of California: no-till annuals (rose clover, soft brome, zorro fescue; ANoT), no-till perennials (blue wildrye, California brome, meadow barley,...

  5. Weed Control with Methyl Bromide Alternatives: A Review.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Methyl bromide (MeBr) has been used for several decades for pre-plant soil fumigation in high value agricultural and horticultural crops because it can provide broad-spectrum control of insects, nematodes, pathogens, and weeds. However, MeBr has been identified as a powerful ozone-depleting chemica...

  6. Identification of seedling cabbages and weeds using hyperspectral imaging

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Target detectionis one of research focues for precision chemical application. This study developed a method to identify seedling cabbages and weeds using hyperspectral spectral imaging. In processing the image data, with ENVI software, after dimension reduction, noise reduction, de-correlation for h...

  7. Implementing strategic weed prevention programs to protect rangeland ecosystems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed prevention is recognized as one of the most cost effective management strategies for invasive plants. A paradigm shift from traditional efforts aimed at controlling established infestations to proactive management before infestations occur is evident in practice and in the literature. Howeve...

  8. Weed control in blackberries using synthetic ground covers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed control in blackberries (Rubus spp.) is a serious problem for organic producers and those who wish to reduce their reliance on herbicides. Three landscape fabrics (Dewitt, Texel, and a white polyester weave) and one industrial grade white on black plastic were used in conjuction with newly pla...

  9. Glyphosate resistant weeds - a threat to conservation agriculture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Glyphosate-resistant weeds are now present throughout the Southeast. Hundreds of thousands of conservation tillage cotton acres, some currently under USDA Natural Resources Conservation Service (NRCS) conservation program contracts, are at risk of being converted to higher-intensity tillage systems....

  10. Acetic acid and weed control in onions (Allium cepa L.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed control is a major challenge in conventional and organic production systems, especially for organically produced sweet onion (Allium cepa L.). Although corn gluten meal shows great promise as an organic preemergent herbicide for onions, research has shown the need for supplemental, postemergen...

  11. Assembly of weed communities along a crop diversity gradient

    Technology Transfer Automated Retrieval System (TEKTRAN)

    1. Increasing cropping system diversity is one strategy for reducing reliance on external chemical inputs in agriculture and may have important implications for agroecosystem functions related to the regulation of weed populations and community assembly. However, the impacts of cropping system dive...

  12. ECOLOGICAL IMPACT OF INTEGRATED CHEMICAL AND BIOLOGICAL AQUATIC WEED CONTROL

    EPA Science Inventory

    This final report presents results of a four-year study of the ecological impacts of chemical, biological, and integrated methods of aquatic weed control. Biological and water quality changes occurred as abundance of macrophytic vegetation was altered by natural factors or manage...

  13. Biocontrol of Weeds with Allelopathy: Conventional and Transgenic Approaches

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Growing highly allelopathic crops has the potential to significantly reduce our reliance on synthetic herbicides for weed management. Specific phytotoxins have been found in allelopathic rice, wheat, and rye varieties, but this information has not been used in breeding varieties that can be markete...

  14. Mustard Seed Meal suppresses Weeds in Potato and Peppermint

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seed meal is a co-product remaining after pressing mustard seed to remove the oil. Seed meals containing high glucosinolates have been reported to have herbicidal activity. Weed suppression with seed meal of Sinapis alba, variety Ida Gold was evaluated in field trials on potatoes and peppermint in ...

  15. Significance of Atrazine in Weed Management Systems of Sweet Corn

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Knowledge of weed management systems being used by sweet corn growers, including the role of atrazine in these systems, is poorly characterized. Management records of 175 fields throughout the major sweet corn production areas of the Midwest were surveyed from 2005 to 2007. Seventy-four percent of s...

  16. Organic weed control in certified organic watermelon production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The increasing perception by consumers that organic food tastes better and is healthier continues to expand the demand for organically produced crops. Field research was conducted in southeast Oklahoma to determine the impact of organic production systems on weed control and watermelon (Citrullus l...

  17. Corn gluten meal for weed control in cowpea, Spring 2008

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cowpea is a major vegetable crop within Oklahoma. It is utilized as both a processing crop by the canning industry and as a fresh market crop for farmer’s and roadside markets. Traditionally weed control in this crop is with preemergence and some postemergence herbicides, but recently fresh market...

  18. Corn gluten meal application equipment evaluations for organic weed control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn gluten meal (CGM) produces an inhibitory effect and reduces root formation in several weed species. One limitation to further use of CGM in vegetable production is the difficulty in achieving a uniform application to the soil surface and detrimental impact of CGM on direct-seeded vegetables. ...

  19. Quantifying the effect of crop spatial arrangement on weed suppression using functional-structural plant modelling.

    PubMed

    Evers, Jochem B; Bastiaans, Lammert

    2016-05-01

    Suppression of weed growth in a crop canopy can be enhanced by improving crop competitiveness. One way to achieve this is by modifying the crop planting pattern. In this study, we addressed the question to what extent a uniform planting pattern increases the ability of a crop to compete with weed plants for light compared to a random and a row planting pattern, and how this ability relates to crop and weed plant density as well as the relative time of emergence of the weed. To this end, we adopted the functional-structural plant modelling approach which allowed us to explicitly include the 3D spatial configuration of the crop-weed canopy and to simulate intra- and interspecific competition between individual plants for light. Based on results of simulated leaf area development, canopy photosynthesis and biomass growth of the crop, we conclude that differences between planting pattern were small, particularly if compared to the effects of relative time of emergence of the weed, weed density and crop density. Nevertheless, analysis of simulated weed biomass demonstrated that a uniform planting of the crop improved the weed-suppression ability of the crop canopy. Differences in weed suppressiveness between planting patterns were largest with weed emergence before crop emergence, when the suppressive effect of the crop was only marginal. With simultaneous emergence a uniform planting pattern was 8 and 15 % more competitive than a row and a random planting pattern, respectively. When weed emergence occurred after crop emergence, differences between crop planting patterns further decreased as crop canopy closure was reached early on regardless of planting pattern. We furthermore conclude that our modelling approach provides promising avenues to further explore crop-weed interactions and aid in the design of crop management strategies that aim at improving crop competitiveness with weeds. PMID:27000875

  20. Classical biological control of invasive teasels (Dipsacus spp.) and other weeds in areas of limited or restricted weed management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Invasive teasels (Dipsacus spp.) are considered noxious in five states and listed as invasive in more than a dozen others, despite having little effect on agriculture. They are problematic in areas of limited weed management such as along highways and railroads and in ditches, wetlands and parks. A ...

  1. 7 CFR 360.304 - Denial of an application for a permit to move a noxious weed; cancelation of a permit to move a...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... noxious weed; cancelation of a permit to move a noxious weed. 360.304 Section 360.304 Agriculture..., DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.304 Denial of an application for a permit to move a noxious weed; cancelation of a permit to move a noxious weed. (a) The Administrator may deny...

  2. 7 CFR 360.304 - Denial of an application for a permit to move a noxious weed; cancelation of a permit to move a...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... noxious weed; cancelation of a permit to move a noxious weed. 360.304 Section 360.304 Agriculture..., DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.304 Denial of an application for a permit to move a noxious weed; cancelation of a permit to move a noxious weed. (a) The Administrator may deny...

  3. 7 CFR 360.304 - Denial of an application for a permit to move a noxious weed; cancelation of a permit to move a...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... noxious weed; cancelation of a permit to move a noxious weed. 360.304 Section 360.304 Agriculture..., DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.304 Denial of an application for a permit to move a noxious weed; cancelation of a permit to move a noxious weed. (a) The Administrator may deny...

  4. 7 CFR 360.304 - Denial of an application for a permit to move a noxious weed; cancelation of a permit to move a...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... noxious weed; cancelation of a permit to move a noxious weed. 360.304 Section 360.304 Agriculture..., DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.304 Denial of an application for a permit to move a noxious weed; cancelation of a permit to move a noxious weed. (a) The Administrator may deny...

  5. The role of plant-microbiome interactions in weed establishment and control.

    PubMed

    Trognitz, Friederike; Hackl, Evelyn; Widhalm, Siegrid; Sessitsch, Angela

    2016-10-01

    The soil microbiome plays an important role in the establishment of weeds and invasive plants. They associate with microorganisms supporting their growth and health. Weed management strategies, like tillage and herbicide treatments, to control weeds generally alter soil structure going alongside with changes in the microbial community. Once a weed population establishes in the field, the plants build up a close relationship with the available microorganisms. Seeds or vegetative organs overwinter in soil and select early in the season their own microbiome before crop plants start to vegetate. Weed and crop plants compete for light, nutrition and water, but may differently interact with soil microorganisms. The development of new sequencing technologies for analyzing soil microbiomes has opened up the possibility for in depth analysis of the interaction between 'undesired' plants and crop plants under different management systems. These findings will help us to understand the functions of microorganisms involved in crop productivity and plant health, weed establishment and weed prevention. Exploitation of the knowledge offers the possibility to search for new biocontrol methods against weeds based on soil and plant-associated microorganisms. This review discusses the recent advances in understanding the functions of microbial communities for weed/invasive plant establishment and shows new ways to use plant-associated microorganisms to control weeds and invasive plants in different land management systems. PMID:27387910

  6. Integrated pest management and weed management in the United States and Canada.

    PubMed

    Owen, Micheal D K; Beckie, Hugh J; Leeson, Julia Y; Norsworthy, Jason K; Steckel, Larry E

    2015-03-01

    There is interest in more diverse weed management tactics because of evolved herbicide resistance in important weeds in many US and Canadian crop systems. While herbicide resistance in weeds is not new, the issue has become critical because of the adoption of simple, convenient and inexpensive crop systems based on genetically engineered glyphosate-tolerant crop cultivars. Importantly, genetic engineering has not been a factor in rice and wheat, two globally important food crops. There are many tactics that help to mitigate herbicide resistance in weeds and should be widely adopted. Evolved herbicide resistance in key weeds has influenced a limited number of growers to include a more diverse suite of tactics to supplement existing herbicidal tactics. Most growers still emphasize herbicides, often to the exclusion of alternative tactics. Application of integrated pest management for weeds is better characterized as integrated weed management, and more typically integrated herbicide management. However, adoption of diverse weed management tactics is limited. Modifying herbicide use will not solve herbicide resistance in weeds, and the relief provided by different herbicide use practices is generally short-lived at best. More diversity of tactics for weed management must be incorporated in crop systems. PMID:25346235

  7. Impact of Fertilizing Pattern on the Biodiversity of a Weed Community and Wheat Growth

    PubMed Central

    Tang, Leilei; Cheng, Chuanpeng; Wan, Kaiyuan; Li, Ruhai; Wang, Daozhong; Tao, Yong; Pan, Junfeng; Xie, Juan; Chen, Fang

    2014-01-01

    Weeding and fertilization are important farming practices. Integrated weed management should protect or improve the biodiversity of farmland weed communities for a better ecological environment with not only increased crop yield, but also reduced use of herbicides. This study hypothesized that appropriate fertilization would benefit both crop growth and the biodiversity of farmland weed communities. To study the effects of different fertilizing patterns on the biodiversity of a farmland weed community and their adaptive mechanisms, indices of species diversity and responses of weed species and wheat were investigated in a 17-year field trial with a winter wheat-soybean rotation. This long term field trial includes six fertilizing treatments with different N, P and K application rates. The results indicated that wheat and the four prevalent weed species (Galium aparine, Vicia sativa, Veronica persica and Geranium carolinianum) showed different responses to fertilizer treatment in terms of density, plant height, shoot biomass, and nutrient accumulations. Each individual weed population exhibited its own adaptive mechanisms, such as increased internode length for growth advantages and increased light interception. The PK treatment had higher density, shoot biomass, Shannon-Wiener and Pielou Indices of weed community than N plus P fertilizer treatments. The N1/2PK treatment showed the same weed species number as the PK treatment. It also showed higher Shannon-Wiener and Pielou Indices of the weed community, although it had a lower wheat yield than the NPK treatment. The negative effects of the N1/2PK treatment on wheat yield could be balanced by the simultaneous positive effects on weed communities, which are intermediate in terms of the effects on wheat and weeds. PMID:24416223

  8. Impact of fertilizing pattern on the biodiversity of a weed community and wheat growth.

    PubMed

    Tang, Leilei; Cheng, Chuanpeng; Wan, Kaiyuan; Li, Ruhai; Wang, Daozhong; Tao, Yong; Pan, Junfeng; Xie, Juan; Chen, Fang

    2014-01-01

    Weeding and fertilization are important farming practices. Integrated weed management should protect or improve the biodiversity of farmland weed communities for a better ecological environment with not only increased crop yield, but also reduced use of herbicides. This study hypothesized that appropriate fertilization would benefit both crop growth and the biodiversity of farmland weed communities. To study the effects of different fertilizing patterns on the biodiversity of a farmland weed community and their adaptive mechanisms, indices of species diversity and responses of weed species and wheat were investigated in a 17-year field trial with a winter wheat-soybean rotation. This long term field trial includes six fertilizing treatments with different N, P and K application rates. The results indicated that wheat and the four prevalent weed species (Galium aparine, Vicia sativa, Veronica persica and Geranium carolinianum) showed different responses to fertilizer treatment in terms of density, plant height, shoot biomass, and nutrient accumulations. Each individual weed population exhibited its own adaptive mechanisms, such as increased internode length for growth advantages and increased light interception. The PK treatment had higher density, shoot biomass, Shannon-Wiener and Pielou Indices of weed community than N plus P fertilizer treatments. The N1/2PK treatment showed the same weed species number as the PK treatment. It also showed higher Shannon-Wiener and Pielou Indices of the weed community, although it had a lower wheat yield than the NPK treatment. The negative effects of the N1/2PK treatment on wheat yield could be balanced by the simultaneous positive effects on weed communities, which are intermediate in terms of the effects on wheat and weeds. PMID:24416223

  9. Patterning highly ordered arrays of complex nanofeatures through EUV directed polarity switching of non chemically amplified photoresist

    PubMed Central

    Ghosh, Subrata; Satyanarayana, V. S. V.; Pramanick, Bulti; Sharma, Satinder K.; Pradeep, Chullikkattil P.; Morales-Reyes, Israel; Batina, Nikola; Gonsalves, Kenneth E.

    2016-01-01

    Given the importance of complex nanofeatures in the filed of micro-/nanoelectronics particularly in the area of high-density magnetic recording, photonic crystals, information storage, micro-lens arrays, tissue engineering and catalysis, the present work demonstrates the development of new methodology for patterning complex nanofeatures using a recently developed non-chemically amplified photoresist (n-CARs) poly(4-(methacryloyloxy)phenyl)dimethylsulfoniumtriflate) (polyMAPDST) with the help of extreme ultraviolet lithography (EUVL) as patterning tool. The photosensitivity of polyMAPDST is mainly due to the presence of radiation sensitive trifluoromethanesulfonate unit (triflate group) which undergoes photodegradation upon exposure with EUV photons, and thus brings in polarity change in the polymer structure. Integration of such radiation sensitive unit into polymer network avoids the need of chemical amplification which is otherwise needed for polarity switching in the case of chemically amplified photoresists (CARs). Indeed, we successfully patterned highly ordered wide-raging dense nanofeatures that include nanodots, nanowaves, nanoboats, star-elbow etc. All these developed nanopatterns have been well characterized by FESEM and AFM techniques. Finally, the potential of polyMAPDST has been established by successful transfer of patterns into silicon substrate through adaptation of compatible etch recipes. PMID:26975782

  10. Patterning highly ordered arrays of complex nanofeatures through EUV directed polarity switching of non chemically amplified photoresist.

    PubMed

    Ghosh, Subrata; Satyanarayana, V S V; Pramanick, Bulti; Sharma, Satinder K; Pradeep, Chullikkattil P; Morales-Reyes, Israel; Batina, Nikola; Gonsalves, Kenneth E

    2016-01-01

    Given the importance of complex nanofeatures in the filed of micro-/nanoelectronics particularly in the area of high-density magnetic recording, photonic crystals, information storage, micro-lens arrays, tissue engineering and catalysis, the present work demonstrates the development of new methodology for patterning complex nanofeatures using a recently developed non-chemically amplified photoresist (n-CARs) poly(4-(methacryloyloxy)phenyl)dimethylsulfoniumtriflate) (polyMAPDST) with the help of extreme ultraviolet lithography (EUVL) as patterning tool. The photosensitivity of polyMAPDST is mainly due to the presence of radiation sensitive trifluoromethanesulfonate unit (triflate group) which undergoes photodegradation upon exposure with EUV photons, and thus brings in polarity change in the polymer structure. Integration of such radiation sensitive unit into polymer network avoids the need of chemical amplification which is otherwise needed for polarity switching in the case of chemically amplified photoresists (CARs). Indeed, we successfully patterned highly ordered wide-raging dense nanofeatures that include nanodots, nanowaves, nanoboats, star-elbow etc. All these developed nanopatterns have been well characterized by FESEM and AFM techniques. Finally, the potential of polyMAPDST has been established by successful transfer of patterns into silicon substrate through adaptation of compatible etch recipes. PMID:26975782

  11. Patterning highly ordered arrays of complex nanofeatures through EUV directed polarity switching of non chemically amplified photoresist

    NASA Astrophysics Data System (ADS)

    Ghosh, Subrata; Satyanarayana, V. S. V.; Pramanick, Bulti; Sharma, Satinder K.; Pradeep, Chullikkattil P.; Morales-Reyes, Israel; Batina, Nikola; Gonsalves, Kenneth E.

    2016-03-01

    Given the importance of complex nanofeatures in the filed of micro-/nanoelectronics particularly in the area of high-density magnetic recording, photonic crystals, information storage, micro-lens arrays, tissue engineering and catalysis, the present work demonstrates the development of new methodology for patterning complex nanofeatures using a recently developed non-chemically amplified photoresist (n-CARs) poly(4-(methacryloyloxy)phenyl)dimethylsulfoniumtriflate) (polyMAPDST) with the help of extreme ultraviolet lithography (EUVL) as patterning tool. The photosensitivity of polyMAPDST is mainly due to the presence of radiation sensitive trifluoromethanesulfonate unit (triflate group) which undergoes photodegradation upon exposure with EUV photons, and thus brings in polarity change in the polymer structure. Integration of such radiation sensitive unit into polymer network avoids the need of chemical amplification which is otherwise needed for polarity switching in the case of chemically amplified photoresists (CARs). Indeed, we successfully patterned highly ordered wide-raging dense nanofeatures that include nanodots, nanowaves, nanoboats, star-elbow etc. All these developed nanopatterns have been well characterized by FESEM and AFM techniques. Finally, the potential of polyMAPDST has been established by successful transfer of patterns into silicon substrate through adaptation of compatible etch recipes.

  12. A Hybrid Differential Invasive Weed Algorithm for Congestion Management

    NASA Astrophysics Data System (ADS)

    Basak, Aniruddha; Pal, Siddharth; Pandi, V. Ravikumar; Panigrahi, B. K.; Das, Swagatam

    This work is dedicated to solve the problem of congestion management in restructured power systems. Nowadays we have open access market which pushes the power system operation to their limits for maximum economic benefits but at the same time making the system more susceptible to congestion. In this regard congestion management is absolutely vital. In this paper we try to remove congestion by generation rescheduling where the cost involved in the rescheduling process is minimized. The proposed algorithm is a hybrid of Invasive Weed Optimization (IWO) and Differential Evolution (DE). The resultant hybrid algorithm was applied on standard IEEE 30 bus system and observed to beat existing algorithms like Simple Bacterial foraging (SBF), Genetic Algorithm (GA), Invasive Weed Optimization (IWO), Differential Evolution (DE) and hybrid algorithms like Hybrid Bacterial Foraging and Differential Evolution (HBFDE) and Adaptive Bacterial Foraging with Nelder Mead (ABFNM).

  13. Identification of Begomoviruses Infecting Crops and Weeds in Belize

    PubMed Central

    McLaughlin, Pamela D.; McLaughlin, Wayne A.; Maxwell, Douglas P.; Roye, Marcia E.

    2010-01-01

    Plants including pepper, red kidney bean, squash, string bean and tomato, as well as weeds with viral symptoms were collected from five districts in Belize over a three year period with the aim of determining the diversity of the begomoviruses present. Sixty five percent of the samples screened via DNA hybridization produced signals indicative of begomovirus infection. Subsequent PCR amplifications and nucleotide sequence analyses revealed the presence of four begomoviruses in Belize. Pepper golden mosaic virus and Tomato mottle virus-[Flo] were found associated with tomato and sweet pepper and the former was also isolated from hot pepper. Merremia mosaic virus was found infecting hot pepper, sweet pepper and the weed species Euphorbia heterophylla. Euphorbia mosaic virus-[Yucatan Peninsula] was found in hot pepper and Euphorbia. This is the first report of the identification of begomoviruses in Belize. PMID:20596296

  14. [Parthenium hysterophorus allergy. A weed problem in India (author's transl)].

    PubMed

    Hausen, B M

    1978-01-01

    Parthenium allergy is caused by direct and indirect contact with Parthenium hysterophorus L. of the Compositae family, accidentally introduced into India from the USA 20 years ago. Its distribution was supported by the optimal environmental conditions of this country. It causes severe contact dermatitis in a lot of people, which becomes chronic after longer exposition. The source of the epidemic are the strong sensitizing sesquiterpene lactones parthenin, ambrosin and others, which are highly concentrated in the trichomes of the plant. During the dry season in India the mature plants crumble to a fine dust, that is scattered by the wind and becomes disseminated throughout the countryside. Permanent contact with this dust is the source of this socalled "airborne contact dermatitis". About 12 deaths occurred in severely affected persons due to intercurrent infection. Control of Parthenium hysterophorus is possible with Ansar-529, a weed-killer containing arsenic. Recently the weed has been introduced into Central-Australia too. PMID:755653

  15. Water Hyacinths and Alligator Weeds for Final Filtration of Sewage

    NASA Technical Reports Server (NTRS)

    Wolverton, B. C.; Mcdonald, R. C.; Gordon, J.

    1976-01-01

    The potential of water hyacinths (Eichhornia crassipes) (Mart.) Solms and alligator weeds (Alternanthera philoxerides) (Mart.) Griesb. as secondary and tertiary filtration systems for domestic sewage was demonstrated. These two vascular aquatic plants reduced the suspended solids, total Kjeldahl nitrogen, total phosphorus, BOD sub 5, and total organic carbon levels in domestic sewage from 60 percent to 98 percent within a two week period. These plants grown in domestic sewage were also free of toxic levels of trace heavy metals.

  16. Stratification requirements for seed dormancy alleviation in a wetland weed.

    PubMed

    Boddy, Louis G; Bradford, Kent J; Fischer, Albert J

    2013-01-01

    Echinochloaoryzicola(syn.E. phyllopogon) is an exotic weed of California rice paddies that has evolved resistance to multiple herbicides. Elimination of seedlingsthroughcertain weed control methods can limit the spread of this weed, but is contingent on accurate predictions of germination and emergence timing, which are influenced by seed dormancy levels.In summer annuals, dormancy can often be relieved through stratification, a period of prolonged exposure to cold and moist conditions.We used population-based threshold models to quantify the effects of stratification on seed germination of four E. Oryzicola populations at a range of water potential (Ψ) and oxygen levels. We also determined how stratification temperatures, moisture levels and durations contributed to dormancy release. Stratification released dormancy by decreasing base Ψ and hydrotimerequired for germination and by eliminating any germination sensitivity to oxygen. Stratification also increased average germination rates (GR), which were used as a proxy for relative dormancy levels. Alternating temperatures nearly doubled GR in all populations, indicating that seeds could be partially dormant despite achieving high final germination percentages. Stratification at Ψ = 0 MPa increased GR compared to stratification at lower water potentials, demonstrating that Ψ contributed to regulating dormancy release. Maximum GR occurred after 2-4 weeks of stratification at 0 MPa; GR were often more rapid for herbicide-resistant than for herbicide-susceptible seeds, implying greater dormancy in the latter. Manipulation of field conditions to promote dormancy alleviation of E. oryzicola seeds might improve the rate and uniformity of germination for seed bank depletion through seedling weed control. Our results suggest field soil saturation in winter would contribute towards E. oryzicola dormancy release and decrease the time to seedling emergence. PMID:24039714

  17. Killing Weeds with 2,4-D. Extension Bulletin 389.

    ERIC Educational Resources Information Center

    Lee, Oliver C.

    Discussed is the use of the herbicide 2,4-D. Though written for farmers and agricultural workers, the pamphlet considers turf weed control and use of 2,4-D near ornamental plants. Aspects of the use of this herbicide covered are: (1) the common forms of 2,4-D; (2) plant responses and tolerances to the herbicide; (3) dilution and concentration of…

  18. Allelopathy in crop/weed interactions--an update.

    PubMed

    Belz, Regina G

    2007-04-01

    Since varietal differences in allelopathy of crops against weeds were discovered in the 1970s, much research has documented the potential that allelopathic crops offer for integrated weed management with substantially reduced herbicide rates. Research groups worldwide have identified several crop species possessing potent allelopathic interference mediated by root exudation of allelochemicals. Rice, wheat, barley and sorghum have attracted most attention. Past research focused on germplasm screening for elite allelopathic cultivars and the identification of the allelochemicals involved. Based on this, traditional breeding efforts were initiated in rice and wheat to breed agronomically acceptable, weed-suppressive cultivars with improved allelopathic interference. Promising suppressive crosses are under investigation. Molecular approaches have elucidated the genetics of allelopathy by QTL mapping which associated the trait in rice and wheat with several chromosomes and suggested the involvement of several allelochemicals. Potentially important compounds that are constitutively secreted from roots have been identified in all crop species under investigation. Biosynthesis and exudation of these metabolites follow a distinct temporal pattern and can be induced by biotic and abiotic factors. The current state of knowledge suggests that allelopathy involves fluctuating mixtures of allelochemicals and their metabolites as regulated by genotype and developmental stage of the producing plant, environment, cultivation and signalling effects, as well as the chemical or microbial turnover of compounds in the rhizosphere. Functional genomics is being applied to identify genes involved in biosynthesis of several identified allelochemicals, providing the potential to improve allelopathy by molecular breeding. The dynamics of crop allelopathy, inducible processes and plant signalling is gaining growing attention; however, future research should also consider allelochemical release

  19. Essential oils from Mediterranean lamiaceae as weed germination inhibitors.

    PubMed

    Angelini, Luciana G; Carpanese, Giovanna; Cioni, Pier Luigi; Morelli, Ivano; Macchia, Mario; Flamini, Guido

    2003-10-01

    The essential oils obtained from rosemary (Rosmarinus officinalis L.), thyme (Thymus vulgaris L.), and savory (Satureja montana L.) and the four monoterpenes that are their major constituents have been analyzed by GC and GC-MS and tested for their allelopathic properties on the seeds of three different annual weeds (Chenopodium album, Portulaca oleracea, and Echinochloa crus-galli) and three crops (Raphanus sativus, Capsicum annuum, and Lactuca sativa), with the aim to evaluate in vitro their potential as germination inhibitors. The essential oil composition varied with the species, thymol being the main constituent (44%) of thyme and carvacrol (57%) that of savory oil. Differences in essential oil composition were observed within two different rosemary ecotypes, type A, with alpha-pinene (37%) and 1,8-cineole (23%), and type B, characterized by a 2-fold content of 1,8-cineole (47%). This latest essential oil inhibited completely the germination of weeds while concurrently displaying little effect on pepper. The other two oils showed less selective action. S. montana essential oil, with 57% carvacrol, is the most active compound, completely inhibiting germination both of crops and weeds. Borneol, one of the main constituents of the oil of rosemary type B, showed an activity comparable to that of the whole oil. Crop and weed seeds treated with 1,8-cineole showed germination values that were not significantly different from controls, even if a slowing of the germination process expressed in terms of a significant increase in mean germination time was observed. Monoterpene compounds also present in the essential oils mainly represented the volatile fraction released from the crops and their residues into the soil. PMID:14518938

  20. Protocols for Robust Herbicide Resistance Testing in Different Weed Species.

    PubMed

    Panozzo, Silvia; Scarabel, Laura; Collavo, Alberto; Sattin, Maurizio

    2015-01-01

    Robust protocols to test putative herbicide resistant weed populations at whole plant level are essential to confirm the resistance status. The presented protocols, based on whole-plant bioassays performed in a greenhouse, can be readily adapted to a wide range of weed species and herbicides through appropriate variants. Seed samples from plants that survived a field herbicide treatment are collected and stored dry at low temperature until used. Germination methods differ according to weed species and seed dormancy type. Seedlings at similar growth stage are transplanted and maintained in the greenhouse under appropriate conditions until plants have reached the right growth stage for herbicide treatment. Accuracy is required to prepare the herbicide solution to avoid unverifiable mistakes. Other critical steps such as the application volume and spray speed are also evaluated. The advantages of this protocol, compared to others based on whole plant bioassays using one herbicide dose, are related to the higher reliability and the possibility of inferring the resistance level. Quicker and less expensive in vivo or in vitro diagnostic screening tests have been proposed (Petri dish bioassays, spectrophotometric tests), but they provide only qualitative information and their widespread use is hindered by the laborious set-up that some species may require. For routine resistance testing, the proposed whole plant bioassay can be applied at only one herbicide dose, so reducing the costs. PMID:26167668

  1. Organic fields sustain weed metacommunity dynamics in farmland landscapes

    PubMed Central

    Henckel, Laura; Börger, Luca; Meiss, Helmut; Gaba, Sabrina; Bretagnolle, Vincent

    2015-01-01

    Agro-ecosystems constitute essential habitat for many organisms. Agricultural intensification, however, has caused a strong decline of farmland biodiversity. Organic farming (OF) is often presented as a more biodiversity-friendly practice, but the generality of the beneficial effects of OF is debated as the effects appear often species- and context-dependent, and current research has highlighted the need to quantify the relative effects of local- and landscape-scale management on farmland biodiversity. Yet very few studies have investigated the landscape-level effects of OF; that is to say, how the biodiversity of a field is affected by the presence or density of organically farmed fields in the surrounding landscape. We addressed this issue using the metacommunity framework, with weed species richness in winter wheat within an intensively farmed landscape in France as model system. Controlling for the effects of local and landscape structure, we showed that OF leads to higher local weed diversity and that the presence of OF in the landscape is associated with higher local weed biodiversity also for conventionally farmed fields, and may reach a similar biodiversity level to organic fields in field margins. Based on these results, we derive indications for improving the sustainable management of farming systems. PMID:25994672

  2. 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. PMID:26314055

  3. Distinct germination response of endangered and common arable weeds to reduced water potential.

    PubMed

    Rühl, A T; Eckstein, R L; Otte, A; Donath, T W

    2016-01-01

    Arable weeds are one of the most endangered species groups in Europe. Modern agriculture and intensive land-use management are the main causes of their dramatic decline. However, besides the changes in land use, climate change may further challenge the adaptability of arable weeds. Therefore, we investigated the response pattern of arable weeds to different water potential and temperature regimes during the phase of germination. We expected that endangered arable weeds would be more sensitive to differences in water availability and temperature than common arable weeds. To this end, we set up a climate chamber experiment where we exposed seeds of five familial pairs of common and endangered arable weed species to different temperatures (5/15, 10/20 °C) and water potentials (0.0 to -1.2 MPa). The results revealed a significant relationship between the reaction of arable weed species to water availability and their Red List status. The effects of reduced water availability on total germination, mean germination time and synchrony were significantly stronger in endangered than in common arable weeds. Therefore, global climate change may present a further threat to the survival of endangered arable weed species. PMID:25786499

  4. Development of remote sensing based site specific weed management for Midwest mint production

    NASA Astrophysics Data System (ADS)

    Gumz, Mary Saumur Paulson

    Peppermint and spearmint are high value essential oil crops in Indiana, Michigan, and Wisconsin. Although the mints are profitable alternatives to corn and soybeans, mint production efficiency must improve in order to allow industry survival against foreign produced oils and synthetic flavorings. Weed control is the major input cost in mint production and tools to increase efficiency are necessary. Remote sensing-based site-specific weed management offers potential for decreasing weed control costs through simplified weed detection and control from accurate site specific weed and herbicide application maps. This research showed the practicability of remote sensing for weed detection in the mints. Research was designed to compare spectral response curves of field grown mint and weeds, and to use these data to develop spectral vegetation indices for automated weed detection. Viability of remote sensing in mint production was established using unsupervised classification, supervised classification, handheld spectroradiometer readings and spectral vegetation indices (SVIs). Unsupervised classification of multispectral images of peppermint production fields generated crop health maps with 92 and 67% accuracy in meadow and row peppermint, respectively. Supervised classification of multispectral images identified weed infestations with 97% and 85% accuracy for meadow and row peppermint, respectively. Supervised classification showed that peppermint was spectrally distinct from weeds, but the accuracy of these measures was dependent on extensive ground referencing which is impractical and too costly for on-farm use. Handheld spectroradiometer measurements of peppermint, spearmint, and several weeds and crop and weed mixtures were taken over three years from greenhouse grown plants, replicated field plots, and production peppermint and spearmint fields. Results showed that mints have greater near infrared (NIR) and lower green reflectance and a steeper red edge slope than

  5. How weeds emerge: a taxonomic and trait-based examination using United States data

    PubMed Central

    Kuester, Adam; Conner, Jeffrey K; Culley, Theresa; Baucom, Regina S

    2014-01-01

    Weeds can cause great economic and ecological harm to ecosystems. Despite their importance, comparisons of the taxonomy and traits of successful weeds often focus on a few specific comparisons – for example, introduced versus native weeds.We used publicly available inventories of US plant species to make comprehensive comparisons of the factors that underlie weediness. We quantitatively examined taxonomy to determine if certain genera are overrepresented by introduced, weedy or herbicide-resistant species, and we compared phenotypic traits of weeds to those of nonweeds, whether introduced or native.We uncovered genera that have more weeds and introduced species than expected by chance and plant families that have more herbicide-resistant species than expected by chance. Certain traits, generally related to fast reproduction, were more likely to be associated with weedy plants regardless of species’ origins. We also found stress tolerance traits associated with either native or introduced weeds compared with native or introduced nonweeds. Weeds and introduced species have significantly smaller genomes than nonweeds and native species.These results support trends for weedy plants reported from other floras, suggest that native and introduced weeds have different stress adaptations, and provide a comprehensive survey of trends across weeds within the USA. PMID:24494694

  6. Airborne gamma-ray spectrometer and magnetometer survey: Weed quadrangle, California. Final report

    SciTech Connect

    Not Available

    1981-05-01

    Volume II contains the flight path, radiometric multi-parameter stacked profiles, magnetic and ancillary parameter stacked profiles, histograms, and anomaly maps for the Weed Quadrangle in California.

  7. Integration of Agronomic Practices with Herbicides for Sustainable Weed Management in Aerobic Rice

    PubMed Central

    Anwar, M. P.; Juraimi, A. S.; Mohamed, M. T. M.; Uddin, M. K.; Samedani, B.; Puteh, A.; Man, Azmi

    2013-01-01

    Till now, herbicide seems to be a cost effective tool from an agronomic view point to control weeds. But long term efficacy and sustainability issues are the driving forces behind the reconsideration of herbicide dependent weed management strategy in rice. This demands reappearance of physical and cultural management options combined with judicious herbicide application in a more comprehensive and integrated way. Keeping those in mind, some agronomic tools along with different manual weeding and herbicides combinations were evaluated for their weed control efficacy in rice under aerobic soil conditions. Combination of competitive variety, higher seeding rate, and seed priming resulted in more competitive cropping system in favor of rice, which was reflected in lower weed pressure, higher weed control efficiency, and better yield. Most of the herbicides exhibited excellent weed control efficiency. Treatments comprising only herbicides required less cost involvement but produced higher net benefit. On the contrary, treatments comprising both herbicide and manual weeding required high cost involvement and thus produced lower net benefit. Therefore, adoption of competitive rice variety, higher seed rate, and seed priming along with spraying different early-postemergence herbicides in rotation at 10 days after seeding (DAS) followed by a manual weeding at 30 DAS may be recommended from sustainability view point. PMID:24223513

  8. Broccoli/weed/soil discrimination by optical reflectance using neural networks

    NASA Astrophysics Data System (ADS)

    Hahn, Federico

    1995-04-01

    Broccoli is grown extensively in Scotland, and has become one of the main vegetables cropped, due to its high yields and profits. Broccoli, weed and soil samples from 6 different farms were collected and their spectra obtained and analyzed using discriminant analysis. High crop/weed/soil discrimination success rates were encountered in each farm, but the selected wavelengths varied in each farm due to differences in broccoli variety, weed species incidence and soil type. In order to use only three wavelengths, neural networks were introduced and high crop/weed/soil discrimination accuracies for each farm were achieved.

  9. Critical period of weed control in oilseed rape in two Moroccan regions.

    PubMed

    Maataoui, A; Bouhache, M; Benbella, M; Talouizte, A

    2003-01-01

    The determination of critical period of weed control in oilseed rape is necessary to know the weed control period. To determine the critical period, two fields experiments were carried out during 1995-96 growth season in Loukkos and Saïs regions at two oilseed densities (D1 = 24 and D2 = 36 plants m(-2)). Ten treatments corresponding to plots left weed free or weeded plots until four leaves, flowers bud, flowering, puds formation, and maturity stages of oilseed rape were tested. Density and biomass of weeds were determined at each oilseed stages. Results showed that weed density and biomass were higher in Saïs than in Loukkos sites. For a 10% yield loss, critical period of weed control in Loukkos was from 458 to 720 degree days after emergence (D degrees AE) and from 480 to 720 D degrees AE in oilseed conducted at densities D1 and D2, respectively. In Saïs, critical period of weed control was from 474 to 738 D degrees AE and from 468 to 675 D degrees AE in oilseed conducted at D1 and D2, respectively. It was concluded that the length of the critical period of weed control in oilseed rape grain yield seems to be dependant of the level of the infestation. PMID:15149131

  10. The development of a phosphite-mediated fertilization and weed control system for rice.

    PubMed

    Manna, Mrinalini; Achary, V Mohan M; Islam, Tahmina; Agrawal, Pawan K; Reddy, Malireddy K

    2016-01-01

    Fertilizers and herbicides are two vital components of modern agriculture. The imminent danger of phosphate reserve depletion and multiple herbicide tolerance casts doubt on agricultural sustainability in the future. Phosphite, a reduced form of phosphorus, has been proposed as an alternative fertilizer and herbicide that would address the above problems to a considerable extent. To assess the suitability of a phosphite-based fertilization and weed control system for rice, we engineered rice plants with a codon-optimized ptxD gene from Pseudomonas stutzeri. Ectopic expression of this gene led to improved root growth, physiology and overall phenotype in addition to normal yield in transgenic plants in the presence of phosphite. Phosphite functioned as a translocative, non-selective, pre- and post-emergent herbicide. Phosphite use as a dual fertilizer and herbicide may mitigate the overuse of phosphorus fertilizers and reduce eutrophication and the development of herbicide resistance, which in turn will improve the sustainability of agriculture. PMID:27109389

  11. The development of a phosphite-mediated fertilization and weed control system for rice

    PubMed Central

    Manna, Mrinalini; Achary, V. Mohan M.; Islam, Tahmina; Agrawal, Pawan K.; Reddy, Malireddy K.

    2016-01-01

    Fertilizers and herbicides are two vital components of modern agriculture. The imminent danger of phosphate reserve depletion and multiple herbicide tolerance casts doubt on agricultural sustainability in the future. Phosphite, a reduced form of phosphorus, has been proposed as an alternative fertilizer and herbicide that would address the above problems to a considerable extent. To assess the suitability of a phosphite-based fertilization and weed control system for rice, we engineered rice plants with a codon-optimized ptxD gene from Pseudomonas stutzeri. Ectopic expression of this gene led to improved root growth, physiology and overall phenotype in addition to normal yield in transgenic plants in the presence of phosphite. Phosphite functioned as a translocative, non-selective, pre- and post-emergent herbicide. Phosphite use as a dual fertilizer and herbicide may mitigate the overuse of phosphorus fertilizers and reduce eutrophication and the development of herbicide resistance, which in turn will improve the sustainability of agriculture. PMID:27109389

  12. Efficacy evaluation of selected herbicides on weed control and productivity evaluation of Bt cotton in Punjab.

    PubMed

    Singh, Kulvir; Rathore, Pankaj

    2015-07-01

    Field experiments were conducted during Kharif 2012 and 2013 to evaluate the efficacy of different herbicides for weed management in cotton. Highest seed cotton yield (3537.3 kg ha(-1)) was recorded in weed free plots followed by pendimethalin @1.0 kg a.i ha(-1) as Pre.em.+quizalofopethyl @50 g a.i ha(-1) post-em at 2-4 weed leaf stage + one hoeing (3318.9 kg ha") owing to improved number of bolls per plant and boll weight. Statistically least yield was recorded underweedy check (1435.4 kg ha(-1)). Application of pyrithiobac sodium could not express any visible toxic effect on crop indicating its selectivity for cotton, although none of the tested new chemicals i.e., pyrithiobac sodium@ 62.5g a.i ha(-1) and quizalofopethyl @50g a.i ha(-1) when applied alone could not outperform the existing recommended chemicals for weed management. Yield losses to the extent of 6.2-59.4% were recorded due to weed competition. Weed control efficiency (WCE) was highest under weed free check (86.8%) followed by pendimethalin @1.0 kg a.i ha(-1) as Pre. em.+quizalofopethyl @50g a.i ha(-1), at 2-4 weed leaf stage + one hoeing (73.7%), whereas minimum values were for weedy check (24.7%). Though net returns (r94660 ha(-1)) were highest for weed free check but higher B:C ratio (2:11) was observed for pendimethalin @1.0 kg a.i ha(-1) as Pre em.+quizalofopethyl @50 g a.i ha(-1) post-em at 2-4 weed leaf stage+one hoeing. Therefore, for reasons such as labor shortage besides their timely availability, using these herbicides in combination with cultural practices could be the practical solution foreconomically efficient and effective weed management. PMID:26364480

  13. The art and science of weed mapping

    USGS Publications Warehouse

    Barnett, David T.; Stohlgren, Thomas J.; Jarnevich, Catherine S.; Chong, Geneva W.; Ericson, Jenny A.; Davern, Tracy R.; Simonson, Sara E.

    2007-01-01

    Land managers need cost-effective and informative tools for non-native plant species management. Many local, state, and federal agencies adopted mapping systems designed to collect comparable data for the early detection and monitoring of non-native species. We compared mapping information to statistically rigorous, plot-based methods to better understand the benefits and compatibility of the two techniques. Mapping non-native species locations provided a species list, associated species distributions, and infested area for subjectively selected survey sites. The value of this information may be compromised by crude estimates of cover and incomplete or biased estimations of species distributions. Incorporating plot-based assessments guided by a stratified-random sample design provided a less biased description of non-native species distributions and increased the comparability of data over time and across regions for the inventory, monitoring, and management of non-native and native plant species.

  14. Precision placement of corn gluten meal for weed control in organic vegetable production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic vegetable producers continue to rank weeds as one of their most troublesome, time consuming, and costly production problems. As a result of the limited number of organically approved weed control herbicides, the precision placement of these materials increases their potential usefulness thr...

  15. Weed-crop competition relationships differ between organic and conventional cropping systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic farmers have identified weed management to be a top research priority and production constraint, as the efficacy of organic weed management is often more variable than conventional herbicide-based methods. The Rodale Institute Farming Systems Trial (FST) provides a unique 27-year history of ...

  16. Number of solaria needed to predict weed seedlings in two summer crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The utility of solaria to predict densities of a few weed species in summer crops had been demonstrated but needed confirmation. We tested the method with additional species and determined the minimum number of solaria required to predict the presence of weed seedlings in the forthcoming growing sea...

  17. Mulching methods for weed control in a certified organic production system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Reducing weed competition is a critical step in organic cropping systems. Use of black plastic as a weed barrier is widely used and effective. The expense associated with black plastic as well as the ecological impact of disposal has a negative impact with its use. Research was conducted at Lane,...

  18. Weed control in sweet bell pepper using sequential postdirected applications of pelargonic acid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pepper (Capsicum annuum) producers would benefit from additional herbicide options that are safe to the crop and provide effective weed control. Research was conducted in southeastern Oklahoma (Atoka County, Lane, OK) during 2010 and 2011 to determine the impact of pelargonic acid on weed control ef...

  19. The mechanism for weed suppression by a forage radish cover crop

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the Mid-Atlantic region, forage radish (Raphanus sativus L. var. longipinnatus) winter cover crops planted prior to 1 September suppress winter annual weeds from fall until early April. Little is known about the mechanism of this weed suppression. Published research reports suggest that allelopat...

  20. Impact of over-the-top broadcast applications of Racer® on onion weed control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The weed control challenges for onion production are formidable; however, these challenges are even greater for those considering organic crop production. Organic onion producers need organic herbicides that can effectively provide post-emergent weed control. Racer (registered trademark) is a poten...

  1. Tine cultivation effects on weed control, productivity, and economics of peanut under organic management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Identifying effective weed control regimes for organic peanut has become paramount for improving the feasibility of organic production. Tine cultivation is a proven effective method at reducing in-row weed populations in several crops. Field trials were therefore conducted in 2008 and 2009 to asse...

  2. WEED COMMUNITY COMPOSITION IN TREE FRUIT NURSERIES TREATED WITH METHYL BROMIDE AND ALTERNATIVE FUMIGANTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Several agricultural cropping systems, for decades, have relied on methyl bromide (MeBr) for pest control including weeds. Alternative fumigants are being sought worldwide because MeBr has been identified as an ozone-layer depleting substance. Weed communities respond dynamically to alterations in...

  3. 2006 UPDATE OF WEED ECOLOGY AND MANAGEMENT RESEARCH IN SWEET CORN

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This report summarizes the results of studies concerning weed ecology and management in sweet corn, including 1) the critical period of weed control and the effect of planting date on the critical period, 2) the influence of giant ragweed interference on sweet corn yield loss and ear traits, 3) how ...

  4. Software to quantify and map vegetative cover in fallow fields for weed management decisions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mapping weed cover during the fallow period of dryland crop rotations would be valuable for weed management in subsequent crops and could be done with low cost color digital cameras, however most managers lack the specialized software and expertise needed to create a map from the images. We develope...

  5. Implements and cultivation frequency to improve in-row weed control in organic peanut production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed control in organic peanut production is difficult and costly, which limits expansion of the production system. Sweep cultivation in the row middles is effective, but weeds remain in the crop row causing yield loss. Research trials were conducted in Tifton, GA to evaluate implements and freque...

  6. Trans-Atlantic Opportunities for Collaboration on Classical Biological Control of Weeds with Plant Pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In North America, introduced invasive weeds are having catastrophic effects on agricultural and natural, wild ecosystems. Many of these weeds have been introduced from Eurasia, and the only economically feasible means for controlling them is through classical biological control. This situation is th...

  7. Impact of broadcast applications of acetic acid on onion injury and weed control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Interest in organic onion production is growing throughout the areas now producing onions with conventional methods, but weed control continues to be a primary obstacle. Weed control is ranked as the number one research priority by organic vegetable producers. The few organic herbicides cleared for ...

  8. A Quarter of a Century of Contributions from the FDWSRU in Biological Control of Weeds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Evaluation of foreign plant pathogens for biological control of weeds was initiated at the United States Department of Agriculture, Agricultural Research Service (ARS) in the mid 1970s. Justification for locating this research effort at the Foreign Disease-Weed Science Research Unit (FDWSRU), Ft. D...

  9. Nematode, Fungi, and Weed Control using Telone C35 and Colored Plastic Mulches

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Methyl bromide fumigation controls weeds, fungi, and nematodes. An alternative treatment system was investigated that used various colored plastic mulches with Telone C35 (65% 1,3- dichloropropene plus 35% chloropicrin). These mulches controlled weeds by a thickness that prevented nutsedge penetrati...

  10. The evolutionary history of an invasive species: alligator weed, Alternanthera philoxeroides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The eco-evolutionary mechanisms of biological invasions are still not thoroughly understood. Alligator weed, Alternanthera philoxeroides (Martius) Gisebach (Amaranthaceae), is a plant native to South America and a weed in Australia and other countries. To better understand its success as an invader,...

  11. PERENNIAL CROP NURSERIES TREATED WITH METHYL BROMIDE AND ALTERNATIVE FUMIGANTS: EFFECT ON WEED COMMUNITY COMPOSTION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed communities can respond dynamically to shifts in management systems. Thus, transition from methyl bromide (MeBr) to alternative fumigants for pre-plant soil treatments may cause shifts in weed species composition. This hypothesis was tested in four perennial crop nurseries in California. The...

  12. The role of climate change and increasing atmospheric carbon dioxide on weed management: Herbicide Efficacy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rising concentrations of carbon dioxide [CO2] and a changing climate will almost certainly affect weed biology and demographics with consequences for crop productivity. The extent of such consequences could be minimal if weed management, particularly the widespread and effective use of herbicides, m...

  13. Preliminary investigation of ethanedintrile for control of weeds and nematodes important in Florida production systems.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A preliminary in vitro experiment was conducted with seeds of several weed species of importance in vegetable and ornamental production systems in Florida, and with root-knot nematode (Meloidogyne incognita) infested soil. The prepared weed and nematode inoculum were placed in open desiccators of m...

  14. Leafy Spurge: An Emerging Model to Study Traits of Perennial Weeds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weeds contain inherent genetic traits that give them remarkable plasticity, allowing them to adapt, regenerate, survive, and thrive in a multitude of ecosystems. Many weeds are capable of vegetative regeneration from tissue which can arise spontaneously from root or stem tissues following tilling or...

  15. Weed seed persistence and microbial abundance in long-term organic and conventional cropping systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed seed persistence in soil can be influenced by many factors, including crop management. This research was conducted to determine whether organic management systems with higher organic amendments and soil microbial biomass could reduce weed seed persistence compared to conventional management sy...

  16. Allelopathic effects of sunnhemp (Crotalaria juncea L.) on germination of vegetables and weeds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sunnhemp (Crotalaria juncea L.) is a tropical legume that could be an important summer cover crop in the Southeastern U.S., but it has the potential for suppressing both crops and weeds. Allelopathic effects of sunnhemp on weeds, vegetable crops, and cover crops were evaluated in growth chamber an...

  17. Mutual benefits through formalized international collaboration on biological control of weeds with plant pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the U.S., introduced invasive weeds have catastrophic effects on agricultural, aquatic, rangeland, riparian, and natural ecosystems. Often the only economically feasible means for controlling these weeds is classical biological control through the introduction of natural enemies, including plant ...

  18. Mulching methods impact on herb production and weed control in a certified organic production system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed control challenges for horticulture production are formidable; however, these challenges are even greater for those considering organic crop production. Black plastic as a weed barrier is widely used and effective. The expense associated with black plastic, as well as the ecological impact of...

  19. Pelargonic acid formulations, application rates, and sequential applications for weed control in squash

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic squash (Cucurbita pepo L.) producers need appropriate herbicides that can effectively provide season- long weed control. Research was conducted in southeast Oklahoma (Atoka County, Lane, OK) to determine the impact of potential organic herbicides on weed control efficacy, crop injury, and y...

  20. Suppressing weed growth after wheat harvest with underseeded red clover in organic farming

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic producers are seeking alternative tactics for weed control so that they can reduce their need for tillage. In this study, we examined cover crop strategies for suppressing weed growth after harvest of wheat. Two cover crop treatments, red clover (mammoth type) or a mixture of oat and dry p...

  1. Impact of mulching methods on herb production and weed control in a certified organic production system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Reducing weed competition is a critical step in organic cropping systems. Use of black plastic as a weed barrier is widely used and effective. The expense associated with black plastic as well as the ecological impact of disposal has a negative impact with its use. Research was conducted at Lane,...

  2. Role of native soil biology in brassicaceae seed meal induced weed suppression.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sustainable methods of nitrogen (N) fertility and weed management are a challenge in organic orchard management systems. Nutrient supply is dependent on decomposition and mineralization of organic matter, yet intensive cultivation commonly used to control weeds can disrupt biological processes cont...

  3. Precision placement of corn gluten meal for weed control in organic vegetable production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Producers of organic vegetables continue to rank weeds as one of their most troublesome, time consuming, and costly production problems. As a result of the limited number of organically approved weed control herbicides, the precision placement of these materials increases their potential usefulness...

  4. Pelargonic acid for weed control in organic Vidalia sweet onion production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cultivation using a tine weeder is a proven means to manage weeds in organic Vidalia® sweet onion production. If the initial cultivation is delayed, emerged weeds are not controlled by the tine weeder. In these cases, herbicides derived from natural products could be used to control the emerged we...

  5. Onion weed control with post-directed applications of pelargonic acid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic onion producers need appropriate herbicides that can effectively provide post-emergent weed control. Research was conducted in southeast Oklahoma (Atoka County, Lane, OK) to determine the impact of a potential organic herbicide on weed control efficacy, crop injury, and yields. The experim...

  6. Broadcast application of scythe for broadleaf weed control in spring-transplanted onions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Producers using organic methods for onion production need organic herbicides that will effectively provide post-emergent weed control. In 2008, a second year of field research was conducted to determine the effect of broadcast over-the-top application of Scythe (57% pelargonic acid) on weed control...

  7. Scythe (57% pelargonic acid) broadcast application for broadleaf weed control in spring-transplanted onions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although previous studies yielded important information concerning use of pelargonic acid as a potential organic herbicide, further research is indicated to increase the understanding of the relationship among application volumes, weed species, and weed maturity on herbicidal efficacy and crop injur...

  8. A susceptible weed host can compromise suppression of Meloidogyne incognita by resistant cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weeds can support nematode reproduction when a non-host or resistant host crop is grown. Meloidogyne incognita, the dominant nematode pathogen of cotton in many areas in the US, reproduces well on prickly sida (Sida spinosa), which is a significant weed in some cotton-producing areas. The developm...

  9. Response of rice genotypes to weed competition in dry direct-seeded rice in India.

    PubMed

    Mahajan, Gulshan; Ramesha, Mugalodi S; Chauhan, Bhagirath S

    2014-01-01

    The differential weed-competitive abilities of eight rice genotypes and the traits that may confer such attributes were investigated under partial weedy and weed-free conditions in naturally occurring weed flora in dry direct-seeded rice during the rainy seasons of 2011 and 2012 at Ludhiana, Punjab, India. The results showed genotypic differences in competitiveness against weeds. In weed-free plots, grain yield varied from 6.6 to 8.9 t ha(-1) across different genotypes; it was lowest for PR-115 and highest for the hybrid H-97158. In partial weedy plots, grain yield and weed biomass at flowering varied from 3.6 to 6.7 t ha(-1) and from 174 to 419 g m(-2), respectively. In partial weedy plots, grain yield was lowest for PR-115 and highest for PR-120. Average yield loss due to weed competition ranged from 21 to 46% in different rice genotypes. The study showed that early canopy closure, high leaf area index at early stage, and high root biomass and volume correlated positively with competitiveness. This study suggests that some traits (root biomass, leaf area index, and shoot biomass at the early stage) could play an important role in conferring weed competitiveness and these traits can be explored for dry-seeded rice. PMID:25093205

  10. Nitrogen competition between corn and weeds in soils under organic and conventional management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cropping systems research has shown that organic systems can have comparable yields to conventional systems at higher weed biomass levels. Higher weed tolerance in organic systems could be due to differences in labile soil organic matter and nitrogen (N) mineralization potential. The objective of ou...

  11. Weed control in yellow squash using sequential postdirected applications of pelargonic acid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Squash (Cucurbita pepo L.) producers would benefit from appropriate herbicides that can effectively provide season-long weed control. Research was conducted in southeast Oklahoma (Atoka County, Lane, OK) during 2010 and 2011 to determine the impact of a naturally derived herbicide on weed control ef...

  12. Maize dwarf mosaic can reduce weed suppressive ability of sweet corn

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Maize dwarf mosaic (MDM) stunts corn growth, delays development, and is the most prevalent viral disease of sweet corn grown in many regions of North America and Europe. Although weeds evade control in most sweet corn fields, the extent to which MDM influences the weed suppressive ability of the cro...

  13. Maize dwarf mosaic in sweet corn contributes to weed growth and seed production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Maize dwarf mosaic (MDM) stunts corn growth, delays development, and is the most prevalent viral disease of sweet corn. Although weeds evade control in most sweet corn fields, the extent to which MDM influences the crop’s weed suppressive ability is unknown. Field studies were conducted over a three...

  14. Influence of planting date and weed interference on sweet corn growth and development

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Crop planting date and canopy density influence interactions between weeds and sweet corn (Zea mays L.); however, little is known about sweet corn growth response to weed interference. Field studies were conducted in 2004 and 2005 near Urbana, Illinois to quantify the influence of planting date and ...

  15. Real World of Industrial Chemistry: The Challenge of Herbicides for Aquatic Weeds.

    ERIC Educational Resources Information Center

    Martin, Dean F.; Martin, Barbara B.

    1985-01-01

    Discusses problems in selecting the correct herbicide for use in controlling aquatic weeds, considering specificity, size of the market, fear of trace contaminants, and herbicide resistance in weeds. Also summarizes some successful herbicides, providing a table listing mode of action of some herbicides used for control of aquatic plants. (JN)

  16. [Effects of different rice farming systems on paddy field weed community].

    PubMed

    Zhang, Dan; Min, Qing-Wen; Cheng, Sheng-Kui; Yang, Hai-Long; He, Lu; Jiao, Wen-Jun; Liu, Shan

    2010-06-01

    Taking the paddy fields planted with glutinous rice and hybrid rice in the traditional agricultural region in Congjiang County of Guizhou Province as the case, and by using semi-experiment combined with random sampling investigation, this paper studied the characteristics of weed community in the paddy fields under rice monoculture (R), rice-fish culture (R-F), and rice-fish-duck culture (R-F-D). Under the three rice farming systems, glutinous rice had higher capability in inhibiting weeds, compared with hybrid rice. Farming system R-F-D decreased the weed density significantly, with the control effect on Monochoia vaginalis and Rotala indica being 100%. The overall weed-inhibiting effect of R-F-D was significantly higher than that of the other farming systems. Under R-F-D, the species richness and Shannon diversity index of weed community decreased markedly, while the Pielou evenness index increased, indicating that the species composition of weed community changed greatly, and the occurrence of native dominant weed species decreased. It was concluded that R-F-D was a feasible farming system for the control of paddy field weed community. PMID:20873641

  17. Living boundaries: tracking weed seed movement with non-dormant seeds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Synthetic seed banks are a useful tool for increasing precision of counts in weed demography studies. By sowing a known number of seeds of a single accession within a spatially well-described area, an investigator can greatly improve the signal to noise ratio, relative to the ambient weed seed bank,...

  18. Promising weed suppressive activity in high-yielding indica rice and hybrid rice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Effective weed control in U.S. rice has relied primarily on herbicides since the 1960s. Several indica rice lines tested in the 1980s suppressed aquatic weeds. Since then, they and their crosses with standard U.S. cultivars, and other indica lines were found to suppress barnyardgrass (Echinochloa ...

  19. Broadcast application of vinegar for broadleaf weed control in spring-transplanted onions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vinegar (acetic acid) is a non-selective contact herbicide used in organic crop production. Research was conducted to determine if vinegar could be successfully applied over the top of onion plants to control broadleaf weeds. The experiment included 6 weed control treatments (2 application volumes...

  20. Remote Sensing of Exotic Invasive Weeds in the Rio Grande System of Texas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Exotic invasive weeds are a serious problem in the Rio Grande system of Texas. This paper presents the results of several aerial remote sensing studies conducted from 2002 to 2006 on the Rio Grande from its mouth near Brownsville in south Texas to El Paso in west Texas. Weed species addressed inc...