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Last update: November 12, 2013.
1

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...

2

Alligator weed  

NSDL National Science Digital Library

Alligator weed is a non-native species of plant in the United States that can damage waterways by clogging them and reducing water flow. Also, it grows in a way that reduces light penetration into the water. Alligator weed is being reduced by a few different insects that were released as biological control agents, such as the alligator weed flea beetle.

Robert H. Mohlenbrock (USDA-NRCS;)

2006-11-12

3

Agronomic Weeds.  

ERIC Educational Resources Information Center

|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…

Hartwig, Nathan L.

4

Flowers & Weeds.  

ERIC Educational Resources Information Center

|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)|

Flannery, Maura C.

1996-01-01

5

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...

6

Weed extraction system, method  

US Patent & Trademark Office Database

A system and method for providing weed extraction so Industrial, Commercial and Home users (ICAHUs) can assure that unwanted weeds can be easily and effectively extracted. The system and method allows ICAHUs to work safely and efficiently and to extract weeds by using a hand-held device that can easily penetrate the ground around weeds, secure the unwanted weed, and aid the user in extracting the weed from the ground. ICAHUs can easily operate the levers of the device which operate jaws to secure to weeds. Specialized debris passages in the jaws of the device allow for debris to be passed through the jaws of the device which allow to for continued use and a greatly reduced need to clean the device during use. The method comprises a system in which unwanted weeds may be easily secured and extracted by the user without an increased risk of accidents or without unnecessary steps or procedures for cleaning.

Carter; Larry (Makawao, HI)

2013-06-25

7

MINT WEED RESEARCH  

Technology Transfer Automated Retrieval System (TEKTRAN)

Weeds lower mint oil yield and quality and weed control represents a major production cost and investment of time for producers of mint oil. The goal of this research is to develop improved weed control methods in spearmint and peppermint and to identify promising new herbicides on spearmint and pe...

8

Introduction to Weeds and Herbicides.  

ERIC Educational Resources Information Center

|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…

Hartwig, Nathan L.

9

BIOLOGICAL CONTROL OF WEEDS  

Microsoft Academic Search

Classical biological control, i.e. the introduction and release of exotic insects, mites, or pathogens to give permanent control, is the predominant method in weed biocontrol. Inundative releases of predators and integrated pest management are less widely used. The United States, Australia, South Africa, Canada, and New Zealand use biocontrol the most. Weeds in natural ecosystems are increasingly becoming targets for

Rachel E. Cruttwell McFadyen

1998-01-01

10

WEED RESEARCH IN MINT  

Technology Transfer Automated Retrieval System (TEKTRAN)

Uncontrolled weeds in peppermint and spearmint reduce mint oil yield and quality. Several weed species have developed resistance to, or are poorly controlled by herbicides labeled for mint production. Flucarbazone, and propoxycarbazone applied to dormant native spearmint caused little or no crop inj...

11

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...

12

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...

13

Operation Weed and Seed.  

National Technical Information Service (NTIS)

Operation Weed and Seed, a U.S. Department of Justice community-based initiative, is an innovative and comprehensive multi-agency approach to law enforcement, crime prevention, and community revitalization.

2008-01-01

14

Crop mimicry in weeds  

Microsoft Academic Search

The selective forces imposed by agricultural practices have resulted in the evolution of agricultural races of weeds or agroecotypes.\\u000a Some agroecotypes are intimately associated with a specific crop. Such associations can involve a system of mimicry, whereby\\u000a the weed resembles the crop at specific stages during its life history and, as a result of mistaken identity, evades eradication.\\u000a Mimetic forms

SPENCER C. H. BARRETT

1983-01-01

15

7 CFR 201.15 - Weed seeds.  

Code of Federal Regulations, 2013 CFR

...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 or transported and shall include noxious weed...

2013-01-01

16

Onion weed control: 2003 transplanted onion weed control trial  

Technology Transfer Automated Retrieval System (TEKTRAN)

Interest in fresh market onion production is increasing in Arkansas, Oklahoma, and north Texas. Effective weed control is essential in sweet onion production because even a small amount of weed competition can result in large reductions in onion yields and quality. Although mechanical weed control...

17

Weed Problems and Weed Control in the Commonwealth Caribbean  

Microsoft Academic Search

The effect of weeds on crops is discussed, with particular reference to the Commonwealth Caribbean. The most serious weeds in the region are Cyperus rotundas, Cynodon dactylon, Commelina spp., Parthenium hysterophorus, Portulaca oleracea, Cleome spp. and Amaranthus spp. Serious weeds include Eleusine indica, Echinochloa colonum, Euphorbia spp., Brachiaria mutica, Paspalum conjugatum, Sporobolus indicus and Ipomoea tiliaceae. Brief notes are given

J. L. Hammerton

1981-01-01

18

Grass and weed killer poisoning  

MedlinePLUS

... by swallowing weed killers containing a chemical called glyphosate. This is for information only and not for ... Glyphosate ... Glyphosate is found in various weed killers, including the brands listed below: Roundup Bronco Glifonox Kleen-up ...

19

WEED CONTROL IN AVOCADO ORCHARDS  

Microsoft Academic Search

Efficient weed control in avocado orchards is a challenging undertaking in most climates, but it is particularly difficult in warm, humid areas where the annual rainfall is 1,000 mm or more. Seed germination and the subsequent growth of most weeds increase with higher temperature and humidity and conversely decrease in cooler and drier weather. The most troublesome weeds in lowland,

Simon E. Malo

20

WEED CONTROL WITH ORGANIC PRODUCTION  

Technology Transfer Automated Retrieval System (TEKTRAN)

Weed management in organic crop production systems requires an integration of cultural and mechanical controls, augmented with thermal and biological tactics. Successful weed control depends on careful integration of these tactics, tailored to the crop, weed species composition, and tillage sy...

21

Weed Management Costs, Weed Best Management Practices, and The Roundup Ready® Weed Management Program  

Microsoft Academic Search

Roundup ready (RR) crops have been widely adopted because they provide significant benefits to growers, but glyphosate resistant weeds threaten the sustainability of these benefits. Several weed best management practices (BMPs) exist to help manage resistance, but these practices could substantially increase weed management costs and so discourage adoption. This paper uses survey results to explore the extent of grower

T. M. Hurley; P. D. Mitchell; G. Frisvold

22

WEED CONTROL NOTES  

Technology Transfer Automated Retrieval System (TEKTRAN)

Weeds in spearmint and peppermint lower oil yield and quality. A popular herbicide, pendimethalin, is no longer available for growers to use this spring. As a result, growers must select among several older or several new preemergence herbicides that are now available. Trifluralin and napropamid...

23

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...

24

Kudzu: Misunderstood Weed  

NSDL National Science Digital Library

In this guided inquiry unit, learn more about kudzu as an invasive species and misunderstood weed, analyze photos of the plant, and make a plan to remove it from an infested area. The unit was developed and tested by The Science House, the mathematics and science learning outreach project of North Carolina State University.

25

Controlling Landscape Weeds.  

ERIC Educational Resources Information Center

|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…

Nuss, James Robert, Jr.

26

EXOTIC AND INVASIVE HERBACEOUS RANGE WEEDS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Resource managers are often discouraged when it comes to the identification of herbaceous rangeland weeds, terminology associated with these weeds, control of these weeds, and the succession of these weeds. The terminology often used in describing herbaceous rangeland weeds (i. e. invasive) often m...

27

Weed Identification and Control in Vegetable Crops.  

ERIC Educational Resources Information Center

|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…

Ferretti, Peter A., Comp.

28

Soil, Weeds, and Computers  

NSDL National Science Digital Library

After a 2001 wildfire in the state of Wyoming, scientists were interested in learning what hydrophobic layers existed in the heavily burned areas and at what depth. In a collaborative, inquiry-based project, high school students collected soil chemistry data that helped biologists learn more about controlling noxious weed invasion. As a result of this collaboration, students became part of the process of science and members of the scientific community.

Mcclennen, Nate

2004-05-01

29

Managing Weeds in Potato Rotations Without Herbicides  

Microsoft Academic Search

Managing weeds without herbicides requires an integration of methods and strategies and a change in how weeds are perceived.\\u000a Weeds should be managed in a holistic, intentional and proactive manner. Understanding the interactions between the cropping\\u000a system and the weed community and managing the cropping system to prevent and discourage weeds and maintain a low weed seedbank\\u000a is necessary for

Rick A. Boydston

2010-01-01

30

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, ...

31

WEED MANAGEMENT ISSUES IN UKRAINE  

Technology Transfer Automated Retrieval System (TEKTRAN)

In 1991, Ukraine became a self-governing country. With the change in government, producers gained freedom to plan their crop production systems. The changes in cropping systems implemented by Ukrainian producers have affected weed dynamics. The purpose of this paper is to inform weed scientists i...

32

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...

33

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...

34

A SYSTEMATIC APPROACH TO PERENNIAL WEED MANAGEMENT  

Technology Transfer Automated Retrieval System (TEKTRAN)

Perennial weeds are prominent in croplands of Ukraine. Scientists in the United States have explored various control tactics to control perennial weeds. This paper describes the basic ecology of perennial weeds, then outlines possible management systems for three prominent perennial weeds. A key...

35

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...

36

Relative abundance in an alien weed flora  

Microsoft Academic Search

Both relative abundance and absolute abundance of alien weed species in a large geographic region increased from the year 1900 to 1980. The increase in relative abundance may have been due to competitive displacement among the weeds, patterns of landscape disturbance, or simply time. The increase in absolute abundance indicates the ineffectiveness of past weed control policies in stemming weed

Frank Forcella; Stephen J. Harvey

1983-01-01

37

Applicator Training Manual for: Aquatic Weed Control.  

ERIC Educational Resources Information Center

|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…

Herron, James W.

38

Integrated weed management in buckwheat  

Microsoft Academic Search

Field experiments were carried out at Mountain Agricultural Research and Extension Centre Sangla during the sum­ mer seasons of 2001 and 2002, to evaluate some herbicides alone and in integration with hand weeding . Three herbi­ cides viz. alachlor 1.50 kg\\/ha, oxyfluorfen 0.20 kg\\/ha and pretilachlor at 1.00 kg\\/ha, alone and at half rates supplement­ ed with one hand weeding

Surendra Singh KANA

39

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...

40

7 CFR 201.50 - Weed seed.  

Code of Federal Regulations, 2013 CFR

...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 and regulations of the...

2013-01-01

41

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...

42

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 ...

43

Weed Control Programs for Southern Rice Production  

Microsoft Academic Search

Barnyardgrass continues to be the most common weed in Arkansas rice produc- tion. Most weed control programs center around controlling barnyardgrass. In 1989, propanil-resistant barnyardgrass was discovered in Poinsett County, AR. Since then, methods have been studied to control this weed. Several new herbicides have been introduced for preemergence (PRE) and postemergence (POST) barnyardgrass control. Most recently, bispyribac-sodium and cyhalofop

B. V. Ottis; R. E. Talbert; E. F. Scherder; M. S. Malik; M. L. Lovelace

44

Allelopathy, a chance for sustainable weed management  

Microsoft Academic Search

The exploitation of crop allelopathy against weeds may be useful to reduce issues related to the use of herbicides. Several crops, such as alfalfa, barley, black mustard, buckwheat, rice, sorghum, sunflower and wheat, demonstrate strong weed suppression ability, either by exuding allelochemical compounds from living plant parts or from decomposing residues. As well as the positive effect on weed reduction,

Franco Tesio; Aldo Ferrero

2010-01-01

45

Weed control in conservation agriculture  

Technology Transfer Automated Retrieval System (TEKTRAN)

Prior to the introduction of the selective herbicide, 2,4-D (2,4-dichlorophenoxyacetic acid), in the 1940’s, weed control in agricultural crops was primarily achieved through mechanical cultivation of the soil. Since that time, an increasing number of highly efficacious herbicide options, paired wi...

46

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...

47

Effect of Weeding Regime and Plant Spacings on Weed Growth and Performance of Transplanted Rice  

Microsoft Academic Search

Effect of weeding regime (unweeded control, hand weeding once, 4 weeks after transplanting (w.a.t.) and hand weeding twice, 4 and 7 w.a.t.) and different plant spacings (20 × 2.5 cm, 20 × 5 cm, 20 × 10 cm, 20 × 15 cm and 20 × 20 cm) on weed growth and performance of transplanted rice were tested in a split-plot

N. U. Ahmed; M. Z. Hoque

1981-01-01

48

Jimson weed abuse in an Oklahoma teen.  

PubMed

Jimson weed, a plant often abused by teenagers and young adults, grows wild throughout Oklahoma. It is best known for its hallucinogenic properties; however intoxication can lead to anticholinergic manifestations that are potentially dangerous. Over the past six years, sixty-three individuals in Oklahoma have been hospitalized for jimson weed intoxication, including this Oklahoma teen. Importance lies in proper identification, understanding, and management in persons presenting with jimson weed poisoning. PMID:20131730

Honey, Brooke L; Hagemann, Tracy M; Lobb, Kelley M; McGoodwin, Lee

2009-12-01

49

Factors which facilitate waste water treatment by aquatic weeds – the mechanism of the weeds’ purifying action  

Microsoft Academic Search

Aquatic weeds such as water hyacinth, salvinia, pistia, and lemna have proved to be powerful bioagents which significantly purify wastewater lying under them. Even the performance of conventional oxidation ponds can be greatly enhanced by the simple expedient of introducing one of these aquatic weeds. Weeds absorb certain pollutants. But the contribution of absorption to the overall treatment is only

Tasneem Abbasi; S. A. Abbasi

2010-01-01

50

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

ERIC Educational Resources Information Center

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…

Lee, Marta

2009-01-01

51

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...

52

ORGANIC WEED MANAGEMENT RESEARCH IN SOUTHWESTERN MINNESOTA  

Technology Transfer Automated Retrieval System (TEKTRAN)

The University of Minnesota received funding in 2002 from the CSREES Organic Conversion Program (OCP) to investigate several weed management strategies for application to organic cropping systems. The first objective is to compare the effects of two organic management systems on annual weed populati...

53

Costs and Benefits of Aquatic Weed Control.  

National Technical Information Service (NTIS)

In order to define the extent of the aquatic weed problem in terms of economic costs and benefits an attempt is made to develop order of magnitude estimates for specific damage caused by weeds in certain settings. These estimates would give a better persp...

E. O. Gangstad

1979-01-01

54

ECONOMICS OF WEED MANAGEMENT: PRINCIPLES AND PRACTICES  

Technology Transfer Automated Retrieval System (TEKTRAN)

Weed scientists and invasive plant biologists must find cost-effective, ecologically-based methods to manage undesirable plants. Economic analyses are needed for management, policymaking and setting research priorities. The fundamental economic principle for weed management is simple: Act only if t...

55

Weed Control Programs That Utilize Less Herbicides  

Microsoft Academic Search

Bermudagrasses are widely used on golf courses throughout the southern United States. Bermudagrass has the potential to provide a high quality turfgrass on greens, tees, and fairways. However, a good turfgrass management program with particular emphasis on weed control must be followed to maintain the desirable quality. Crabgrass and goosegrass are common problem summer annual weeds that infest most bermudagrass

B. J. Johnson; T. R. Murphy

56

WEED MANAGEMENT WITH COVER CROP MULCHES  

Technology Transfer Automated Retrieval System (TEKTRAN)

Residue from desiccated cover crops can play a significant role in integrated weed management systems. Weed suppression by cover crop residue is influenced by many factors including the quantity, physical properties, and chemical properties of the residue as well as the sensitivity of the affected ...

57

Weed Control in Energy Forest Production.  

National Technical Information Service (NTIS)

The aim of the work was to collect, analyse and present experiences from mechanical and chemical weed control. The drainage status of the soil have to be good if mechanical control shall be used. Chemical weed control with soil-active herbicides requires ...

B. Danfors

1985-01-01

58

WEED CONTROL FOR COLORADO FARMERS AND WHEAT PRODUCERS  

Technology Transfer Automated Retrieval System (TEKTRAN)

For crop producers, weeds represent the most complex and expensive pest management challenge that must be addressed on an annual basis. Weeds frequently reduce crop yields by 20 to 50% by their competition for water, nutrients, and sunlight. Weed control is complicated because there are many weeds...

59

Participatory development of weed management technologies in Benin  

Microsoft Academic Search

Keywords: permanent land use, weeds, indigenous knowledge, integrated crop and soil management, participatory learning, co-researchWeeds constitute a major constraint to agricultural production in the Republic of Benin. Agricultural intensification and the evolution towards permanent cropping systems have 1ed to the emergence of novel weed problems. A diagnostic study identified speargrass (Imperata cylindricd) and the parasitic weed Striga spp. as major

P. V. Vissoh

2006-01-01

60

Influence of glyphosate-resistant cropping systems on weed species shifts and glyphosate-resistant weed populations  

Microsoft Academic Search

Glyphosate-resistant (GR) crops have facilitated increases in conservation tillage production practices and simplified weed control in GR corn, soybean, canola and cotton. Increased reliance on glyphosate, many times as the only active ingredient used, has resulted in weed species shifts and the evolution of weed populations resistant to glyphosate. However, weed shifts and the evolution of herbicide resistance are not

William G. Johnson; Vince M. Davis; Greg R. Kruger; Stephen C. Weller

2009-01-01

61

Weed Mapping with CoKriging Using Soil Properties  

Microsoft Academic Search

Our aim is to build reliable weed maps to control weeds in patches. Weed sampling is time consuming but there are some shortcuts. If an intensively sampled variable (e.g. soil property) can be used to improve estimation of a sparsely sampled variable (e.g. weed distribution), one can reduce weed sampling. The geostatistical estimation method co-kriging uses two or more sampled

Torben Heisel; Christian Andreasen

1999-01-01

62

A study of weeding policies in eleven TALON resource libraries.  

PubMed Central

A study was made of the weeding policies and practices of eleven TALON resource libraries. The results indicated that although weeding, or collection evaluation as it is also known, was performed by most of the libraries, few had a written policy. The reasons for weeding and the types of weeding done by the libraries are described. A discussion of the prevalent means of disposition of withdrawn materials and of the obstacles to cooperative weeding is included.

Goldstein, C H

1981-01-01

63

Using Weeds and Wildflowers to Study Plants.  

ERIC Educational Resources Information Center

|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)|

Nowak, Nancy

1984-01-01

64

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....

65

Cultivation of Pleurotus ostreatus on weed plants.  

PubMed

Oyster mushroom, Pleurotus ostreatus (Jacq.:Fr.) Kumm. ITCC 3308 (collected from Indian Type Culture Collection, IARI, New Delhi, India, 110012) was grown on dry weed plants, Leonotis sp, Sida acuta, Parthenium argentatum, Ageratum conyzoides, Cassia sophera, Tephrosia purpurea and Lantana camara. Leonotis sp. was the best substrate in fruit body production of P. ostreatus when it was mixed with rice straw (1:1, wet wt/wet wt) for mushroom cultivation. The fruiting time for P. ostreatus was also less on Leonotis sp. than on any other weed substrates tested in the present investigation. T. purpurea was the least suited weed for oyster mushroom cultivation. The main problem of oyster mushroom cultivation on weed substrates was found to be low yield in the second flush that could be overcome by blending weed plants with rice straw. The protein contents of the fruit bodies obtained from Cassia sophera, Parthenium argentatum and Leonotis sp. were not only better than rice straw but also from the rice straw supplemented weeds. PMID:17161599

Das, Nirmalendu; Mukherjee, Mina

2006-12-11

66

INTERACTIONS BETWEEN WEED SEEDLING RECRUITMENT, SURFACE RESIDUE, AND SOIL-BASED WEED MANAGEMENT PRACTICES  

Technology Transfer Automated Retrieval System (TEKTRAN)

Use of no-tillage cropping systems can result in the presence of crop and/or cover crop residue on the surface of soils during the time of crop and weed establishment. Research during the past decade has demonstrated the selective impact that residue can exert on recruitment of various weed species...

67

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...

68

Federal Resource Guide for Weed and Seed Communities.  

National Technical Information Service (NTIS)

The Community Capacity Development Office (CCDO) has prepared this guide to assist in implementing the Weed and Seed strategy in the community. This guide is organized by topical keyword within each of the Weed and Seed strategy elements: Law Enforcement/...

2005-01-01

69

Weed and Seed Strategy. Site Coordinators' Training Guide.  

National Technical Information Service (NTIS)

The Community Capacity Development Office (CCDO) recognizes the unique challenges that new Weed and Seed site coordinators (site coordinators) face as they struggle to implement the Weed and Seed strategy in both new and existing sites. The site coordinat...

2010-01-01

70

Funding needed for assessments of weed biological control  

Treesearch

Title: Funding needed for assessments of weed biological control ... efforts are therefore devoted to reducing weed abundance in agricultural and natural settings. Effective options for reducing invasive abundance and spread are few, although ...

71

Weed Control of Growing Stands of Energy Forests.  

National Technical Information Service (NTIS)

Investigations that would lead to the selection of suitable methods of weed control in growing stands of energy forests were started. Different methods of accomplishing the weed control measures, i.e., both mechanical and chemical methods must be availabl...

O. Noren B. Danfors A. Stambeck

1983-01-01

72

An Ultrasonic System for Weed Detection in Cereal Crops  

PubMed Central

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 assessed by discriminant analysis. The ultrasonic readings permitted the separation between weed infested zones and non-infested areas with up to 92.8% of success. This system will potentially reduce the cost of weed detection and offers an opportunity to its use in non-selective methods for weed control.

Andujar, Dionisio; Weis, Martin; Gerhards, Roland

2012-01-01

73

Guidelines for management of noxious weeds at Hanford  

SciTech Connect

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.

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

1995-10-27

74

GLYPHOSATE-RESISTANT WEEDS: CURRENT STATUS AND FUTURE OUTLOOK  

Technology Transfer Automated Retrieval System (TEKTRAN)

Introduction of glyphosate-resistant transgenic crops has revolutionized weed management. GR crops as weed management tools have allowed farmers to manage weeds more effectively and economically. High levels of adoption of GR crops by U.S. farmers have dramatically increased the use of glyphosate,...

75

TEAK (TECTONA GRANDIS) GROWTH IN RESPONSE TO WEED CONTROL TREATMENTS  

Microsoft Academic Search

dijalankan untuk menguji keberkesanan tujuh rawatan kawalan rumpai dalam jati (Tectona grandis) di negeri Kerala, di kawasan semenanjung India. Glifosfat, parakuat, 2,4 -D + dalapon, 'manual weeding', ring weeding' (parakuat) dan 'ring weeding (manual)'digunakan dua kali dalam selang masa satutahun, pada satu dirian jati yang bertimur 14 bulan. Ukuran tumbesaran direkodkan pada 5 bulan, 10 bulan dan 22 bulan selepas

E. V. Anoop; B. Mohan Kumar; C. T. Abraham

76

MANAGING INVASIVE PLANTS IN NATURAL AREAS: MOVING BEYOND WEED CONTROL  

Microsoft Academic Search

Exotic invasive plants present one of the greatest challenges to natural resource management. These weeds can alter entire communities and ecosystems, substantially degrading important ecosystem services such as forage for wild and domestic herbivores, water and soil quality, recreational values, and wildlife habitat. Traditionally, weed management in natural areas has focused on removing the target weed under the assumption that

Dean Pearson; Yvette Ortega

77

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...

78

A Century of Progress in Weed Control in Hardwood Seedbeds  

Microsoft Academic Search

Weeds have existed in nurseries since before the time Bartram grew hardwoods during the 18th century. Hand weeding was the primary method of weed control during the first part of the 20th century. From 1931 to 1970, advances in chemistry increased the use of herbicides, and advances in engineering increased the reliance on machines for cultivation. Many managers now rely

David B. South

79

WEED INVASION AND DIVERSITY RELATIONSHIPS IN PASTURE COMMUNITIES  

Technology Transfer Automated Retrieval System (TEKTRAN)

Ecological research has shown that high plant diversity can reduce weed invasion in some plant communities. In 1999, we began a study to determine whether greater forage diversity in cool season pastures could reduce weed abundance. The study consisted of three components. First, weed abundance wa...

80

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, ...

81

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...

82

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...

83

Starter Fertilizer Effects On Cotton Development And Weed Interference  

Microsoft Academic Search

Application of postemergence-directed herbi- cides in cotton (Gossypium hirsutum L.) requires a height differential between the crop and weeds. Weeds may respond more to starter fertilizer than cotton, and the enhanced weed growth could adversely affect the height differential, herbicide effectiveness, and reduce lint yields. A field experi- ment was conducted to determine the effect of type and placement of

J. E. Toler; E. C. Murdock; J. J. Camberato

2004-01-01

84

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...

85

WEED SEEDBANK DYNAMICS IN THREE ORGANIC FARMING CROP ROTATIONS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Weed management is a primary concern of organic farmers. Crop rotation is an important potential management approach for maintaining low soil weed seed populations in organic farming systems. This research was conducted to determine the effect of three organic crop rotations on the weed seedbank d...

86

Phenological observations on shrubs to predict weed emergence in turf  

Microsoft Academic Search

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

Roberta Masin; Maria Clara Zuin; Giuseppe Zanin

2005-01-01

87

A Survey of Weeds in Organic Farming in Sweden  

Microsoft Academic Search

The weed flora on 57 arable fields on 17 farms employing organic farming was recorded. With the ordination technique pCCA (partial Canonical Correspondence Analysis) the relative importance of some farming practices was evaluated (crop, preceding crop, ± undersown ley, ± weed harrowing, ± weed hoeing, ploughing regime, ± compost, ± animal husbandry, ± biodynamic agriculture). The variables that explained most

N. T. Rydberg; P. Milberg

2000-01-01

88

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,...

89

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

ERIC Educational Resources Information Center

|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…

Doersch, R. E.; And Others

90

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

PubMed Central

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.

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

2013-01-01

91

Molecular Biology and Genomics: New Tools for Weed Science  

NSDL National Science Digital Library

Some 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 manage weeds, they continue to interfere with crop production. There is clearly much to learn about weeds, information that could aid in weed management and improve competitiveness in nonweedy species. The tools of molecular biology have been enlisted in ongoing efforts to manage weeds, most notably in the development and commercialization of crop plants tailored to resist certain herbicides. Molecular biology also has been used to gain a better understanding of how weeds compete and interact with neighboring plants, survive harsh environmental conditions, and evolve resistance to the herbicides used to control them. The next generation of molecular biology tools, such as genomic resources, may yield novel weed management strategies and shed new light on what makes plants weedy.

Patrick Tranel (University of Illinois;College of Agricultural, Consumer, and Environmental Sciences)

2009-03-01

92

Weed Suppression by Seven Clover Species  

Microsoft Academic Search

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

Shirley M. Ross; Jane R. King; R Cesar C. Izaurralde; John T. ODonovan

2001-01-01

93

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 ...

94

Weed Science and Technology. MP-17.  

ERIC Educational Resources Information Center

|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…

Alley, Harold P.; Lee, Gary A.

95

Optical weed detection and evaluation using reflection measurements  

NASA Astrophysics Data System (ADS)

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.

Vrindts, Els; de Baerdemaeker, Josse

1999-01-01

96

Performance evaluation of a crop\\/weed discriminating microsprayer  

Microsoft Academic Search

An intelligent real-time microspraying weed control system was developed. The system distinguishes between weed and crop plants and a herbicide (glyphosate) is selectively applied to the detected weed plants. The vision system captures 40 RGB images per second, each covering 140mm by 105mm with an image resolution of 800×600 pixels. From the captured images the forward velocity is estimated and

Henrik Skov Midtiby; Solvejg K. Mathiassen; Kim Johan Andersson; Rasmus Nyholm Jørgensen

2011-01-01

97

Innovations in parasitic weeds management in legume crops. A review  

Microsoft Academic Search

Parasitic weeds decrease severely the production of major grain and forage legumes. The most economically damaging weeds for\\u000a temperate legumes are broomrapes, in particular Orobanche crenata. Broomrape species such as Orobanche foetida, Orobanche minor, and Phelipanche aegyptiaca can also induce high local damage. Other parasitic weeds such as Striga gesnerioides and Alectra vogelii decrease yield of legume crops throughout semi-arid

Diego Rubiales; Mónica Fernández-Aparicio

98

Activity of mesotrione on resistant weeds in maize.  

PubMed

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

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

2002-09-01

99

Critical Period of Weed Control in Aerobic Rice  

PubMed Central

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.

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

2012-01-01

100

7 CFR 360.200 - Designation of noxious weeds.  

Code of Federal Regulations, 2013 CFR

...Miramar weed) Ipomoea aquatica Forsskal (water-spinach, swamp morning-glory) Lagarosiphon major (Ridley) Moss Limnophila sessiliflora (Vahl) Blume (ambulia) Melaleuca quinquenervia (Cavanilles) S.T. Blake...

2013-01-01

101

What makes a weed a weed: life history traits of native and exotic plants in the USA  

Microsoft Academic Search

I compared ten life history traits (vegetative reproduction, breeding system, compatibility, pollination system, shade tolerance, habitat, life span, life form, morphology, and toxicity) from two existing databases for the 19,960 plant species that occur in the USA. I used two-way tests of independence to determine if there were significant life history traits that distinguish weeds from non-weeds, exotic weeds from

Steve Sutherland

2004-01-01

102

WEED CONTROL FOR COLORADO FARMERS AND WHEAT PRODUCERS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Crop producers will use this handbook to address complex and expensive weed management challenges that must be on an annual basis. The purpose of this handbook was to summarize the various complexities of weed control issues for dry-land and irrigated agricultural practices in the Central Great Plai...

103

Executive Office for Weed and Seed Implementation Manual.  

National Technical Information Service (NTIS)

The manual is intended to provide an easy-to-read guide for communities attempting to implement a Weed and Seed strategy. It must be provided to each new site that is Officially Recognized or funded by the Executive office for Weed and Seed (EOWS). This m...

2001-01-01

104

National Evaluation of Weed and Seed. Shreveport Case Study.  

National Technical Information Service (NTIS)

Unveiled in 1991, Operation Weed and Seed represents an ambitious attempt to improve the quality of life in America's cities. The ultimate goals of Weed and Seed are to control violent crime, drug trafficking, and drug-related crime in targeted high-crime...

T. Dunworth G. Mills G. Cordner C. Roberts K. Jacoby

1999-01-01

105

Valuing the Roundup Ready® Soybean Weed Management Program  

Microsoft Academic Search

This study examines soybean grower adoption of the Roundup Ready® (RR) weed management program with and without a residual herbicide application, and grower concerns regarding weed resistance to herbicides using telephone survey data from of 357 growers in 2007. It also estimates the pecuniary and non-pecuniary benefits enjoyed by growers from their RR program. The results indicate that soybean growers

Stephen Aultman; Terrance M. Hurley; Paul D. Mitchell; George B. Frisvold

2009-01-01

106

Predictable risk to native plants in weed biological control  

Microsoft Academic Search

Data on field host use of 112 insects, 3 fungi, 1 mite, and 1 nematode established for biological control of weeds in Hawaii, the continental United States, and the Caribbean indicate that the risk to native flora can be judged reliably before introduction. Virtually all risk is borne by native plant species that are closely related to target weeds. Fifteen

Robert W. Pemberton

2000-01-01

107

FORAGE DIVERSITY AND WEED ABUNDANCE RELATIONSHIPS IN GRAZED PASTURE COMMUNITIES  

Technology Transfer Automated Retrieval System (TEKTRAN)

Studies have shown that weed invasion into grasslands may be suppressed in diverse plant communities. Our main objective was to determine whether increased forage plant diversity in pasture communities could help reduce weed abundance in the aboveground vegetation and soil seed bank. We also teste...

108

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...

109

Allelopathic Interactions and Allelochemicals: New Possibilities for Sustainable Weed Management  

Microsoft Academic Search

Weeds are known to cause enormous losses due to their interference in agroecosystems. Because of environmental and human health concerns, worldwide efforts are being made to reduce the heavy reliance on synthetic herbicides that are used to control weeds. In this regard the phenomenon of allelopathy, which is expressed through the release of chemicals by a plant, has been suggested

H. P. Singh; Daizy R. Batish; R. K. Kohli

2003-01-01

110

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...

111

Weed manipulation for insect pest management in corn  

NASA Astrophysics Data System (ADS)

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.

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

1980-11-01

112

CARROT WEED CONTROL - RESEARCH WITH CAPAROL AND NORTON  

Technology Transfer Automated Retrieval System (TEKTRAN)

In regions with mild winters and where potatoes are grown in rotation with carrots, volunteer potato is often the most troublesome weed because it is difficult to control. No herbicides are currently labeled for use in carrots that suppresses volunteer potato. Hand weeding is costly and may remove...

113

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...

114

GROWTH RESPONSE OF WEED AND CROP SEEDLINGS TO DELETERIOUS RHIZOBACTERIA  

Technology Transfer Automated Retrieval System (TEKTRAN)

Selected bacterial isolates previously demonstrated to be suppressive toward weed species in the laboratory were tested for effectiveness under greenhouse conditions. Rhizobacteria varied in ability to inhibit growth of host or other weed species. Some bacterial isolates caused up to 75% growth in...

115

Phytotoxicity of sesquiterpene lactone parthenin on aquatic weeds  

Microsoft Academic Search

The sesquiterpene lactone parthenin, one of the major toxins in an obnoxious weed, parthenium (Parthenium hysterophorus L.), was toxic at 50 ppm to the floating aquatic weeds pistia (Pistia stratiotes L.) and lemna (Lemna pausicostata Hegelm.) and at 100 ppm to water hyacinth (Eichhornia crassipes Mart Solmns.), salvinia (Salvinia molesta Mitchell), azolla (Azolla nilotica Decne.), and spirodella (Spirodella polyrhiza L.

D. K. Pandey

1996-01-01

116

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...

117

Use of Synthetic Ground Covers to Control Weeds in Blackberries  

Microsoft Academic Search

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 and one industrial grade white on black plastic were evaluated for weed control in conjuction with newly planted ‘Kiowa’ root cuttings in Feb. 2006 at a site near Monte Alto, Texas (26°N Lat.). In

D. J. Makus

2011-01-01

118

How to Identify and Control Water Weeds and Algae.  

ERIC Educational Resources Information Center

|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…

Applied Biochemists, Inc., Mequon, WI.

119

APPLICATIONS OF SOIL AND RHIZOSPHERE MICROORGANISMS IN SUSTAINABLE WEED MANAGEMENT  

Technology Transfer Automated Retrieval System (TEKTRAN)

Biological control as a single tactic approach for controlling weeds in cultivated crops has not been as efficacious as those approaches involving herbicides and other cultural methods. Bioherbicides designed for application of deleterious rhizobacteria (DRB) to soil for suppression of weed seedling...

120

Weed Suppression by Seven Clover Species  

SciTech Connect

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.

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

2001-01-01

121

Long-term experiments with reduced tillage in spring cereals. I. Effects on weed flora, weed seedbank and grain yield  

Microsoft Academic Search

In four field experiments lasting from autumn 1993 to 2000, perennial weeds and overwintering weed species increased with reduced tillage compared to ploughing in autumn or spring. Abundant species were Cirsium arvense, Elymus repens, Matricaria perforata, Poa annua and Stellaria media. With no-tillage, grassland perennials were detected. Volunteer oats increased in plots without ploughing. A combination of glyphosate and post-emergence

K. Semb Tørresen; R. Skuterud; H. J. Tandsæther; M. Bredesen Hagemo

2003-01-01

122

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

ERIC Educational Resources Information Center

|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…

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

123

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 ...

124

Profitability of chemical weed control in ginger ( Zingiber officinale Roscoe) production in Northern Nigeria  

Microsoft Academic Search

An economic assessment on the use of chemical weed control in ginger production in 1990 and 1991 indicated substantial reduction in labour requirement with the use of herbicides. The amount and consequently the cost of mulching was also reduced when herbicides instead of manual hand weeding was used as a weed control method. Although comparable yields to the hand weeding

L. Aliyu; S. T. O. Lagoke

2001-01-01

125

EVALUATION OF PLANT BREEDING APPROACHES TO IMPROVE WEED MANAGEMENT IN SWEETPOTATO  

Technology Transfer Automated Retrieval System (TEKTRAN)

Weed management in sweetpotato is expensive, because most acreage is hand weeded. Thus, application of plant breeding approaches to reduce the expense of weed control may be feasible. Some sweetpotato varieties are allelopathic to certain weeds due to production of a group of phytotoxic compounds r...

126

Use of weeds as traditional vegetables in Shurugwi District, Zimbabwe  

PubMed Central

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 livelihoods was ubiquitously perceived, with all participants reporting their contribution towards food security and nutrition. Conclusion The present study confirm findings from similar studies conducted elsewhere that rural households engage in harvesting of wild edible vegetables and other non-timber forest products (NTFPs) as a survival strategy. Based on their potential nutritional and medicinal value, edible weeds could contribute in a major way to food security, basic primary health care and balanced diets of rural households and possibly urban households as well.

2013-01-01

127

Hierarchical Bayesian methods estimate invasive weed impacts at pertinent spatial scales  

Microsoft Academic Search

Invasive weed impact estimates are needed to determine whether or not weeds warrant costly control measures. Typically, land\\u000a managers seek local weed impact estimates (e.g. ranches, parks) and policy-makers want to know how weeds are impacting entire\\u000a regions. Our goal was to provide local and regional impact estimates for a ubiquitous invasive weed: leafy spurge (Euphorbia esula L.). The specific

Matthew J. Rinella; Edward C. Luschei

2007-01-01

128

Crofton weed (Eupatorium adenophorum) toxicity in horses.  

PubMed

The clinical signs and pathology of 6 field cases of a respiratory disease of horses which occurs in the coastal hinterland of south-eastern Queensland are described. The condition has occurred for many years and has been thought to have been associated with ingestion of Crofton weed (Eupatorium adenophorum). Coughing, rapid heaving respiration, decreased exercise tolerance and loss of condition were seen in affected horses. In longstanding cases fibrosis, alveolar lining cell proliferation, oedema, neutrophil infiltration and abscessation were seen. In some cases vascular thrombosis and infarction occur in the lungs. Similar signs and lesions occurred in one horse fed E. adenophorum for 8 months and early lesions in another fed the flowering stage of the plant for about 6 weeks. Lesions also developed in 2 rabbits experimentally fed the plant, but not in sheep or rats. PMID:571272

O'Sullivan, B M

1979-01-01

129

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...

130

Bonneville Power Administration, Lower Columbia Region: Noxious weed management.  

National Technical Information Service (NTIS)

During the 1996 season Office Document Architecture (ODA) executed the contract between Bonneville Power Administration (BPA) and ODA. Execution of this contract included the following activities: Survey for target noxious weeds, such as Gorse; collection...

1996-01-01

131

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 ...

132

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

PubMed

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, such as Escherichia coli, Mycobacterium smegmatis and Pseudoxylaria spp., exhibit characteristics of both weed and non-weed species. We propose that the concept of nonweeds represents a 'dustbin' group that includes species such as Synodropsis spp., Polypaecilum pisce, Metschnikowia orientalis, Salmonella spp., and Caulobacter crescentus. We show that microbial weeds are conceptually distinct from plant weeds, microbial copiotrophs, r-strategists, and other ecophysiological groups of microorganism. Microbial weed species are unlikely to emerge from stationary-phase or other types of closed communities; it is open habitats that select for weed phenotypes. Specific characteristics that are common to diverse types of open habitat are identified, and implications of weed biology and open-habitat ecology are discussed in the context of further studies needed in the fields of environmental and applied microbiology. PMID:23336673

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

2013-01-22

133

Weed seed loss due to predation in Michigan maize fields  

Microsoft Academic Search

The influence of weed seed predation by invertebrates and vertebrates was examined in relation to distance from hedgerows in maize fields of southwestern Michigan. Experiments were conducted in spring and winter and included five common weed species, i.e., velvet-leaf (Abutilon theophrasti), redroot pigweed (Amaranthus retroflexus), common lamb's-quarters (Chenopodium album), fall panicum (Panicum dichotomiflorum), and yellow foxtail (Setaria lutescens). In the

Paul C. Marino; Katherine L. Gross; Douglas A. Landis

1997-01-01

134

Weeds and Domesticates: Evolution in the man-made habitat  

Microsoft Academic Search

Summary  Weeds evolved, and are still evolving, within the man-made habitat in three principal ways: from colonizers through selection\\u000a towards adaptation to continuous habitat disturbance; as derivatives of hybridization between wild and cultivated races of\\u000a domestic species; and through selection towards re-establishing natural seed dispersal mechanisms in abandoned domesticates.\\u000a Domesticates differ from weeds primarily in degree of dependency on man for

J. M. J. De Wet; J. R. Harlan

1975-01-01

135

75 FR 68945 - Update of Noxious Weed Regulations  

Federal Register 2010, 2011, 2012, 2013

We are amending the regulations governing the importation and interstate movement of noxious weeds by adding definitions of terms used in the regulations, adding details regarding the process of applying for the permits used to import or move noxious weeds, adding a requirement for the treatment of niger seed, and adding provisions for petitioning to add a taxon to or remove a taxon from the......

2010-11-10

136

Weed harrowing in winter cereal under semi-arid conditions  

Microsoft Academic Search

Five field experiments on barley and wheat have been carried out in North-Eastern Spain on the same field during the cropping seasons 1999-00 to 2003-04 to compare the effect of different harrowing adjustments on weed control, weed bio- mass and cereal yield. The variables considered were harrowing timing (pre- or early post-emergence), one or two passes, travelling direction, harrowing depth

Tecnología Agraria; G. Pardo; A. Cirujeda; J. Aibar; J. Cavero; C. Zaragoza

137

Agricultural Robotic Platform with Four Wheel Steering for Weed Detection  

Microsoft Academic Search

A robotic platform for mapping of weed populations in fields was used to demonstrate intelligent concepts for autonomous vehicles in agriculture which may eventually result in a new sustainable model for developed agriculture. The vehicle presented here is adapted to operate in 0·25 and 0·5m row crops and equipped with cameras for row guidance and weed detection. A modular approach

Thomas Bak; Hans Jakobsen

2004-01-01

138

Integrated weed management practices in garlic crop in Pakistan  

Microsoft Academic Search

Weed management studies in garlic crop were conducted during 2000–2001 and 2002–2003 at the National Agricultural Research Center, Islamabad Pakistan. During first year, pendimethalin was sprayed at 0.80l a.i.ha?1 pre emergence 2 days after first irrigation in moist condition followed by different mechanical weeding regimes. During second year, pendimethalin, oxadiazon, glyphosate, and metribuzin were sprayed at 0.80l, 0.25l, 0.6l, and

Tariq Mehmood; Khalid Mahmood Khokhar; Muhammad Shakeel

2007-01-01

139

Robust Crop and Weed Segmentation under Uncontrolled Outdoor Illumination  

PubMed Central

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).

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

2011-01-01

140

Robust crop and weed segmentation under uncontrolled outdoor illumination.  

PubMed

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

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

2011-06-10

141

36 CFR 222.8 - Cooperation in control of estray or unbranded livestock, animal diseases, noxious farm weeds, and...  

Code of Federal Regulations, 2010 CFR

...animal diseases, noxious farm weeds, and use of pesticides...animal diseases, noxious farm weeds, and use of pesticides...agencies in the application and enforcement of all laws and regulations...sanitation and noxious farm weeds. (2) The Animal...

2009-07-01

142

36 CFR 222.8 - Cooperation in control of estray or unbranded livestock, animal diseases, noxious farm weeds, and...  

Code of Federal Regulations, 2010 CFR

...animal diseases, noxious farm weeds, and use of pesticides...animal diseases, noxious farm weeds, and use of pesticides...agencies in the application and enforcement of all laws and regulations...sanitation and noxious farm weeds. (2) The Animal...

2010-07-01

143

36 CFR 222.8 - Cooperation in control of estray or unbranded livestock, animal diseases, noxious farm weeds, and...  

Code of Federal Regulations, 2013 CFR

...animal diseases, noxious farm weeds, and use of pesticides...animal diseases, noxious farm weeds, and use of pesticides...agencies in the application and enforcement of all laws and regulations...sanitation and noxious farm weeds. (2) The Animal...

2013-07-01

144

Classification of a broadleaf weed, a grassy weed, and corn using image processing techniques  

NASA Astrophysics Data System (ADS)

Development of a machine vision device to automatically identify different weed species within a field is needed to design a successful spatially variable herbicide applicator. This study was conducted to develop a computer vision algorithm that can successfully identify a broadleaf weed (velvetleaf, Abutilon theophrasti), a grassy weed (wild proso millet, Panicum miliacem), and corn (Zea mays, L.). Digital images were collected in laboratory and field conditions for all three plant species. Image analysis techniques were used to analyze the possibility of using a combination of size and shape features to produce a classification scheme. Two separate approaches were used to classify the velvetleaf from the wild proso millet and corn, and the wild proso millet from the corn. The first and second invariant central moment of inertia measurements along with plant perimeter were used to separate the velvetleaf from the monocot species. Due to the similar shapes of wild proso millet and corn, we were unable to classify the two species by only using size and shape features. Consequently, a two step approach was utilized. This involved using projected perimeter to determine the age (number of days after emergence) of the plant. By knowing the possible age of the plant, the wild proso millet and corn were classified using a combination of length and circularity. Future research will involve the evaluation of several other image features to determine the best classification scheme. Further data will also be collected from a library of laboratory and field images in order to increase the confidence interval of the classification scheme.

Dickson, Monte A.; Bausch, Walter C.; Howarth, M. Scott

1995-01-01

145

Natural metabolites for parasitic weed management.  

PubMed

Compounds of natural origin, such as phytotoxins produced by fungi or natural amino acids, could be used in parasitic weed management strategies by interfering with the early growth stages of the parasites. These metabolites could inhibit seed germination or germ tube elongation, so preventing attachment to the host plant, or, conversely, stimulate seed germination in the absence of the host, contributing to a reduction in the parasite seed bank. Some of the fungal metabolites assayed were very active even at very low concentrations, such as some macrocyclic trichothecenes, which at 0.1 microM strongly suppressed the germination of Orobanche ramosa L. seeds. Interesting results were also obtained with some novel toxins, such as phyllostictine A, highly active in reducing germ tube elongation and seed germination both of O. ramosa and of Cuscuta campestris Yuncker. Among the amino acids tested, methionine and arginine were particularly interesting, as they were able to suppress seed germination at concentrations lower than 1 mM. Some of the fungal metabolites tested were also able to stimulate the germination of O. ramosa seeds. The major findings in this research field are described and discussed. PMID:19266492

Vurro, Maurizio; Boari, Angela; Evidente, Antonio; Andolfi, Anna; Zermane, Nadjia

2009-05-01

146

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...

147

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...

148

75 FR 23151 - Noxious Weeds; Old World Climbing Fern and Maidenhair Creeper  

Federal Register 2010, 2011, 2012, 2013

...APHIS-2008-0097] Noxious Weeds; Old World Climbing Fern and Maidenhair Creeper AGENCY...noxious weed regulations by adding Old World climbing fern (Lygodium microphyllum...we amended the regulations by adding Old World climbing fern (Lygodium...

2010-05-03

149

Classification of Maize and Weeds by Bayesian Networks  

NASA Astrophysics Data System (ADS)

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.

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

2007-11-01

150

Research on crop and weed identification by NIR spectroscopy  

NASA Astrophysics Data System (ADS)

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.

Pan, Jiazhi; Tang, Yueming; He, Yong

2007-01-01

151

Discrimination of corn, grasses and dicot weeds by their UV-induced fluorescence spectral signature  

Microsoft Academic Search

Real-time spot spraying of weed patches requires the development of sensors for the automatic detection of weeds within a\\u000a crop. In this context, the potential of UV-induced fluorescence of green plants for corn-weed discrimination was evaluated.\\u000a A total of 1 440 spectral signatures of fluorescence were recorded in a greenhouse from three plant groups (four corn hybrids,\\u000a four dicotyledonous weed species

Louis Longchamps; Bernard Panneton; Guy Samson; Gilles D. Leroux; Roger Thériault

2010-01-01

152

A Special Vegetation Index for the Weed Detection in Sensor Based Precision Agriculture  

Microsoft Academic Search

Many technologies in precision agriculture (PA) require image analysis and image- processing with weed and background differentiations.\\u000a The detection of weeds on mulched cropland is one important image-processing task for sensor based precision herbicide applications.\\u000a The article introduces a special vegetation index, the Difference Index with Red Threshold (DIRT), for the weed detection\\u000a on mulched croplands. Experimental investigations in weed

Hans-R. Langner; Hartmut Böttger; Helmut Schmidt

2006-01-01

153

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...

154

WEEDTURF: A PREDICTIVE MODEL TO AID CONTROL OF ANNUAL SUMMER WEEDS IN TURF  

Technology Transfer Automated Retrieval System (TEKTRAN)

Predicting weed emergence is useful for planning weed management programs with limited herbicide use. Unfortunately, our ability to anticipate initial emergence and subsequent levels of emergence from simple field observations or weather reports are not good enough to achieve optimal control. Weed e...

155

STATUS OF BIOLOGICAL CONTROL OF WEEDS IN HAWAII AND IMPLICATIONS FOR MANAGING NATIVE ECOSYSTEMS  

Microsoft Academic Search

Biological control of weeds in Hawaii dates back almost 90 years. Seventy-three species of insects and one disease organism have been introduced in an effort to control 21 species of weeds. Forty-three of these •introduced species of insects and one species of fungus have become established on 19 weeds. In 11 cases, populations of the phytophagous organisms have been sufficiently

George P. Markin; Po-Yung Lai; George Y. Funasaki

156

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...

157

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

ERIC Educational Resources Information Center

|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)|

Agricultural Research Service (USDA), Washington, DC.

158

Critical periods of weed control in naturally green colored cotton BRS Verde  

Microsoft Academic Search

Cotton with naturally colored fiber is increasing as a commercial crop due specially to its textile processing with reduced environmental impact, as dying is not necessary. The critical period of weed control and the weed community were studied in a field with the naturally green colored fiber cv. BRS Verde cultivated in Missão Velha, Brazil. Without weed control during all

Gleibson D. Cardoso; Pedro L. C. A. Alves; Liv S. Severino; Leandro S. Vale

2011-01-01

159

Proactive Versus Reactive Management of Glyphosate-Resistant or Tolerant Weeds 1  

Microsoft Academic Search

The value of glyphosate has been compromised in some fields where weed populations have developed resistance or tolerant species increased. Three case studies related to reduced control from glyphosate are: (1) a weed population that has become resistant to glyphosate, with horseweed in Tennessee as an example; (2) a weed population increases due to lack of control in ''glyphosate only''

THOMAS C. MUELLER; PAUL D. MITCHELL; BRYAN G. YOUNG; A. STANLEY CULPEPPER

2005-01-01

160

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...

161

A weed risk assessment model for use as a biosecurity tool evaluating plant introductions  

Microsoft Academic Search

New plant taxa from around the world continue to be imported into Australia and New Zealand. Many of these taxa have the potential to become agricultural or environmental weeds and this risk needs to be assessed before allowing their entry. A weed risk assessment system is described that uses information on a taxon's current weed status in other parts of

P. C. Pheloung; P. A. Williams; S. R. Halloy

1999-01-01

162

The critical period of weed control in common bean ( Phaseolus vulgaris L.) in Cameroon  

Microsoft Academic Search

Field experiments were conducted in 1993 and 1995 in Cameroon to determine the critical period of weed control in common bean (Phaseolus vulgaris L.), and the effect of location and cultivar. Bean yield loss increased with increasing duration of weed interference, and decreased with increasing duration of weed control. The critical period occurred between emergence and second trifoliate leaf for

M. Ngouajio; J. Foko; D. Fouejio

1997-01-01

163

More Than Just Low-Hanging Fruit: A Collaborative Approach to Weeding in Academic Libraries  

Microsoft Academic Search

This article focuses on using collaboration to develop and implement a comprehensive and systematic approach to weeding in a small academic library. Collection assessment, analysis of options, and determination of feasibility form the basis for the development of the weeding agenda. Collaborative strategies that include the creation of a collection management committee, the formation of weeding teams, and the inclusion

Amy K. Soma; Lisa M. Sjoberg

2010-01-01

164

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...

165

Implementation of Image Processing Technique in Real Time Vision System for Automatic Weeding Strategy  

Microsoft Academic Search

A weed can be thought of as any plant growing in the wrong place at the wrong time and doing more harm than good. Weeds compete with the crop for water, light, nutrients and space, and therefore reduce crop yields and also affect the efficient use of machinery. The most widely used method for weed control is to use agricultural

M. M. Mustafa; A. Hussain; K. H. Ghazali; S. Riyadi

2007-01-01

166

Quantitative and qualitative evaluation of weed seed bank in organic farming  

Microsoft Academic Search

The influence of organic farming on weed seed bank under two different crop rotations: with and without manure, was investigated in an organic farm of Kazliskiai over the period of 1997-2002. Proven by qualitative index, organic farming increases the diversity of weed species. Seeds of 10 weed species were found in one experimental field at the beginning of a transition

V. Boguzas; A. Marcinkeviciene

2004-01-01

167

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...

168

WHY RAGWEED PARTHENIUM IS NOT A PERNICIOUS WEED IN THE CONTINENTAL USA?  

Technology Transfer Automated Retrieval System (TEKTRAN)

Ragweed parthenium has achieved major weed status in India and Australia within the past few decades. In the continental USA (48 contiguous states), ragweed parthenium is not a major weed despite close proximity to its native range. We provide rationale for why ragweed parthenium is not a major weed...

169

Weed Invasion Susceptibility Prediction (WISP) Model for Use with Geographic Information Systems  

Microsoft Academic Search

The Weed Invasion Susceptibility Prediction (WISP) model was developed as an extension of the ArcView Geographic Information System to predict potential risk of invasion by individual weed species in rangelands. Existence potential was determined by comparing growth requirements of each weed species with respect to nine site characteristics obtained from geographic data layers: distance from water and disturbance sources, elevation,

J. H. Gillham; A. L. Hild; J. H. Johnson; E. R. Hunt; T. D. Whitson

2004-01-01

170

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 ...

171

Status of weeds as reservoirs of plant parasitic nematodes in banana fields in Martinique  

Microsoft Academic Search

During a survey of the nematodes associated with weeds in banana fields in Martinique, 41 weed species in 37 genera from 20 plant families were collected to extract nematodes from the roots. Results of this survey showed that 24 weed species were hosts of Radopholus similis, 23 were hosts of Helicotylenchus spp., 13 were hosts of Pratylenchus spp., 13 were

Patrick Quénéhervé; Christian Chabrier; Annemie Auwerkerken; Patrick Topart; Bernard Martiny; S. Marie-Luce

2006-01-01

172

Phenological observations on shrubs to predict weed emergence in turf  

NASA Astrophysics Data System (ADS)

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.

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

2005-09-01

173

Using Bayesian networks with rule extraction to infer the risk of weed infestation in a corn-crop  

Microsoft Academic Search

This paper describes the modeling of a weed infestation risk inference system that implements a collaborative inference scheme based on rules extracted from two Bayesian network classifiers. The first Bayesian classifier infers a categorical variable value for the weed–crop competitiveness using as input categorical variables for the total density of weeds and corresponding proportions of narrow and broad-leaved weeds. The

Gláucia M. Bressan; Vilma A. de Oliveira; Estevam R. Hruschka Jr.; Maria do Carmo Nicoletti

2009-01-01

174

Twelfth-year response of Douglas-fir to area of weed control and herbaceous versus woody weed control treatments1  

Microsoft Academic Search

Coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) response to eight weed control treatments was measured 12 years after planting at two Oregon sites. Treatments included four areas of weed control around individual trees (0.375, 1.49, 3.35, and 5.95 m2), no weed control (check), total vegetation control, control of herbaceous competition only, or control of woody competition only. Douglas-fir growth

Robin Rose; Lee S. Rosner; J. Scott Ketchum

175

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

PubMed Central

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.

2010-01-01

176

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...

177

WEEDS OF WHEAT FIELDS OF VILLAGE QAMBAR, DISTRICT SWAT, PAKISTAN  

Microsoft Academic Search

Twenty three species of 13 families were identified as weeds of wheat fields from five different localities of village Qambar, District Swat, during April, 2007. Density, frequency, cover and importance values for each species were calculated. The families in decreasing order of number of species were Brassicaceae (5 Spp.), Fabaceae (4 Spp), Caryophyllaceae (3 Spp) and Poaceae (2 Spp). The

Naveed Akhtar; Farrukh Hussain

178

Invaders, weeds and the risk from genetically manipulated organisms  

Microsoft Academic Search

Invaders, weeds and colonizers comprise different but overlapping sets of species. The probability of successful invasion is low. The 10:10 rule state that 10% of introduced speices (those with feral individuals) become established, 10% of established species (those with self-sustaining populations) become pests. The rule gives an adequate fit to British plant data. The rule predicts that invaders will be

M. Williamson

1993-01-01

179

National Evaluation of Weed and Seed. Cross-Site Analysis.  

National Technical Information Service (NTIS)

Operation Weed and Seed represent an ambitious Federal, State, and local attempt to improve the quality of life in targeted high-crime areas of America's cities. First launched by the U.S. Department of Justice in 1991, the program is designed to control ...

T. Dunworth G. Mills G. Cordner J. Greene

1999-01-01

180

Some Prospects for Aquatic Weed Management in Guyana.  

National Technical Information Service (NTIS)

The report is aof a three-day workshop on the management and utilization of aquatic plants, to formulate recommendations for implementation by local authorities to (1) deal with the aquatic weed problem, particularly by utilizing the vegetation as a resou...

1973-01-01

181

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 ...

182

HYDRILLA, THE PERFECT AQUATIC WEED, BECOMES MORE NOXIOUS THAN EVER  

Technology Transfer Automated Retrieval System (TEKTRAN)

Hydrilla [Hydrilla verticillata (L.F.) Royale] was introduced in Florida lakes 50 years ago and is now one of the most serious aquatic weed problems in the United States. This plant possesses numerous mechanisms of vegetative reproduction that enables it to spread very rapidly. Management of this ...

183

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...

184

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...

185

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

ERIC Educational Resources Information Center

|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,…

O'Dell, Charli

1998-01-01

186

Chemical Basis for Weed Suppressive Activity of Sorghum  

Technology Transfer Automated Retrieval System (TEKTRAN)

The weed suppressive activity of Sorghum species has been associated with phytotoxic compounds that are exuded from the roots, and contain primarily sorgoleone (1). The concentration of 1 ranges from about 40 to 800 ug/mg root extract, based on quantitative analysis of seven genetically different S...

187

Introduced weeds pollinated by introduced bees: Cause or effect?  

Microsoft Academic Search

In the present review we attempt to synthesize evidence for a causative relationship between the presence of non-native bee pollinators and the successful establishment and spread of intro- duced weed species. Using data drawn from the literature and from our own survey conducted in New Zealand, we show that introduced bees favor foraging on introduced plant species, and that in

M. E. HANLEY; D. GOULSON

2003-01-01

188

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...

189

Weed Killer Deforms Sex Organs in Frogs, Study Finds  

NSDL National Science Digital Library

This Web site discusses current research findings surrounding the use of the weed killer, atrazine, and sex organ deformities in frogs exposed to it. The article from the New York Times summarizes the recent research report; free registration is required to view it. This site reports focus on the potential impact of atrazine on humans, but they do raise it as an important question.

Press., Associated

2002-01-01

190

CARROT WEED CONTROL - RESEARCH WITH CAPAROL AND NORTRON  

Technology Transfer Automated Retrieval System (TEKTRAN)

Volunteer potato is frequently a problem in regions with mild winters and where potatoes are grown in rotation with carrots. No herbicides are currently labeled for use in carrots that suppress volunteer potato. Hand weeding is usually required to remove potatoes at a cost of $150 to $250/acre. V...

191

Black bean production: Cover crops, tillage, and weed competition  

Technology Transfer Automated Retrieval System (TEKTRAN)

Winter cover crops can reduce soil erosion by protecting the soil surface and enhance soil tilth, soil moisture, and nutrient availability by increasing soil organic matter. Winter cover crops can also interact with the tillage/planting and weed control system to improve spring planted crops. The ...

192

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...

193

The Effects of Flame Weeding on Soil Microbial Biomass  

Microsoft Academic Search

The effects of liquefied petroleum gas (LPG) flaming on soil microbial biomass and soil temperature were studied in a laboratory trial. The trial was arranged to imitate the most common weed flaming practice, non-selective flaming pre-emergence of the crop. Soil samples were taken, without disturbing the soil surface, before the germination of the crop from a field cultivated and sown

J. Rahkonen; J. Pietikäinen; H. Jokela

1999-01-01

194

Future weed, pest and disease problems for plants  

Technology Transfer Automated Retrieval System (TEKTRAN)

As climate and atmospheric carbon dioxide [CO2] shift in response to anthropogenic change, the outbreak and damage induced by agricultural pests, principally weeds, insects, and diseases may increase. Although the interaction of climate/[CO2] and the impact of agricultural pests has been recognized...

195

Using fast fourier transform for weed detection in corn fields  

Microsoft Academic Search

Agriculture plays one of the most important roles in economy and therefore lowering costs and improving quality of agricultural products is highly demanded. Controlling weeds is one of the most important and also expensive labors in agriculture which can be automated using robotic cultivators. These robots should be armed with a digital camera which uses a method to classify between

Hossein Nejati; Zohreh Azimifar; Mohsen Zamani

2008-01-01

196

Organic Weed Control in White Lupin (Lupinus albus L.)  

Technology Transfer Automated Retrieval System (TEKTRAN)

Legumes such as white lupin (Lupinus albus L.) provide a valuable nitrogen source in organic agriculture. With organic farming becoming an increasing sector of US agriculture and white lupin interest increasing in the southeastern USA because winter hardy cultivars are available, non-chemical weed c...

197

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...

198

Herbicide Leaching Column for a Weed Science Teaching Laboratory.  

ERIC Educational Resources Information Center

|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)|

Ahrens, W. H.

1986-01-01

199

REVEGETATION GUIDELINES FOR WESTERN MONTANA: CONSIDERING INVASIVE WEEDS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Revegetation is a major method for managing areas seriously infested with invasive weeds because it can be used to establish a healthy plant community that is resistant to invasion. Objectives were to help improve revegetation success by providing practical concepts and effective methods to establis...

200

Solanum viarum: Weed reservoir of plant viruses in Florida  

Microsoft Academic Search

Solanum viarum Dunal (tropical soda apple), an introduced and rapidly spreading weed, currently infests over 60 000 ha in Florida. Approximately 220 plants were sampled in seven stands of S. viarum in south?west and west central Florida during 1992 and 1993 to determine the occurrence of nine viruses which can infect solanaceous crops. Virus detection utilized a double antibody sandwich?enzyme

R. J. McGovern; J. E. Polston; J. J. Mullahey

1994-01-01

201

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...

202

Corn gluten meal application options for weed control  

Technology Transfer Automated Retrieval System (TEKTRAN)

Weeds are often mentioned as the most troublesome problem facing organic vegetable producers. It has been documented that corn gluten meal (CGM), a by-product of the wet-milling process of corn, is phytotoxic. As a preemergence or preplant-incorporated herbicide CGM inhibits root development, decr...

203

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...

204

Herbicide Leaching Column for a Weed Science Teaching Laboratory.  

ERIC Educational Resources Information Center

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)

Ahrens, W. H.

1986-01-01

205

Evolution of weed beet ( Beta vulgaris L.) seed bank: Quantification of seed survival, dormancy, germination and pre-emergence growth  

Microsoft Academic Search

Weed beet is an important weed of sugar beet crops. Weed and cropped beets can cross easily and the management of weed beet is therefore crucial in the case of the advent of GM sugar beet, especially herbicide-tolerant cultivars, in order to ensure the co-existence of GM and non-GM crops and to avoid the appearance of herbicide-resistant weed beet. The

M. Sester; C. Dürr; H. Darmency; N. Colbach

2006-01-01

206

Weed control in rice with metham-sodium.  

PubMed

Metam-sodium is a soil fumigant with herbicidal properties. A field experiment was conducted in 2000 at Copiano (Pavia, Italy) to determine the efficacy of three rates of metam-sodium (300, 450 and 600 l/ha) at three different planting times (5, 12 and 18 days after chemical treatments) for the control of weeds in rice cultivation. The study mainly focused on the control of red rice (Oryza sativa var. selvatica), a weed which is worldwide distributed in rice fields and difficult to eradicate Test design was a split-plot with four replications. The main plot size was 13, 5 by 15 m and the subplot size was 13, 5 by 5 m. The chemical treatments were carried out as pre-sowing. Two days after chemical treatments, all field plots were flooded with 10 cm of water as practiced locally. An early variety of rice (Loto) was sown at 150 kg/ha. Weed control was visually evaluated as a percentage of ground covering by all weeds and by each weed individually at three, four and five weeks after treatments. Observations were made also on rice selectivity, and rice grain yield was assessed at the end. Metam-sodium did not injure the rice plants. Metam-sodium at 450 l/ha controlled 100%, 97% and 92% of red rice at the first, second and third observations, respectively. Good results were also obtained with metam-sodium at 300 and 600 l/ha, which controlled 94 to 82% of red rice during the season. Echinochloa crus-galli was better controlled with the higher rates of metam-sodium, particularly in the early part of the season. Metam-sodium did not show enough efficacy in this study against Heteranthera reniformis, Bulboschoenus maritimus and Lindernia spp. The best rice grain yield was obtained with all rates of metam-sodium, when rice was sown 5 days after treatment. PMID:17390826

Sparacino, A C; Ferro, R; Riva, N; Ditto, D; Tano, F; Croce, G; Rabasse, J M

2006-01-01

207

Identification of Begomoviruses Infecting Crops and Weeds in Belize  

PubMed Central

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.

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

2010-01-01

208

Deciphering the evolution of herbicide resistance in weeds.  

PubMed

Resistance to herbicides in arable weeds is increasing rapidly worldwide and threatening global food security. Resistance has now been reported to all major herbicide modes of action despite the development of resistance management strategies in the 1990s. We review here recent advances in understanding the genetic bases and evolutionary drivers of herbicide resistance that highlight the complex nature of selection for this adaptive trait. Whereas early studied cases of resistance were highly herbicide-specific and largely under monogenic control, cases of greatest concern today generally involve resistance to multiple modes of action, are under polygenic control, and are derived from pre-existing stress response pathways. Although 'omics' approaches should enable unraveling the genetic bases of complex resistances, the appearance, selection, and spread of herbicide resistance in weed populations can only be fully elucidated by focusing on evolutionary dynamics and implementing integrative modeling efforts. PMID:23830583

Délye, Christophe; Jasieniuk, Marie; Le Corre, Valérie

2013-07-02

209

Weed density and diversity under glyphosate-resistant crop sequences  

Microsoft Academic Search

The effect of regular and exclusive application of glyphosate in crop sequences on associated weed composition, richness and diversity was studied over five years. Three sequences (wheat–soybean, soybean monoculture and soybean–maize) including soybean and maize glyphosate-resistant cultivars were investigated under two tillage systems (conventional or no-tillage). Regardless of sequence and tillage system, regular glyphosate application appeared to reduce richness and

E. Puricelli; D. Tuesca

2005-01-01

210

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

ERIC Educational Resources Information Center

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…

Lee, Oliver C.

211

Stratification Requirements for Seed Dormancy Alleviation in a Wetland Weed  

PubMed Central

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 (?) and oxygen levels. We also determined how stratification temperatures, moisture levels and durations contributed to dormancy release. Stratification released dormancy by decreasing base ? 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 ??=?0 MPa increased GR compared to stratification at lower water potentials, demonstrating that ? 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.

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

2013-01-01

212

Stratification requirements for seed dormancy alleviation in a wetland weed.  

PubMed

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 (?) and oxygen levels. We also determined how stratification temperatures, moisture levels and durations contributed to dormancy release. Stratification released dormancy by decreasing base ? 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 ??=?0 MPa increased GR compared to stratification at lower water potentials, demonstrating that ? 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

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

2013-09-05

213

Data Weeding Techniques Applied to Roget’s Thesaurus  

Microsoft Academic Search

\\u000a It can be difficult to automatically generate “nice” graphical representations for concept lattices from lexical databases,\\u000a such as Roget’s Thesaurus, because the data sources tend to be large and complex. This paper discusses a variety of “data\\u000a weeding” techniques that can be applied in order to reduce the size of a concept lattice, first in general, and then with\\u000a respect

Uta Priss; L. John Old

214

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

ERIC Educational Resources Information Center

|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…

Lee, Oliver C.

215

A Rotary-wing Unmanned Air Vehicle for Aquatic Weed Surveillance and Management  

Microsoft Academic Search

This paper addresses the novel application of an autonomous rotary-wing unmanned air vehicle (RUAV) as a cost-effective tool\\u000a for the surveillance and management of aquatic weeds. A conservative estimate of the annual loss of agricultural revenue to\\u000a the Australian economy due to weeds is in the order of A$4 billion, hence the reason why weed control is of national significance.

Ali Haydar Gökto?an; Salah Sukkarieh; Mitch Bryson; Jeremy Randle; Todd Lupton; Calvin Hung

2010-01-01

216

Weed control and yield response of soil solarization with different plastic films in lettuce  

Microsoft Academic Search

Phase out of most chemicals available for weed management renewed the interest in soil solarization as a technically effective and environmentally safe practice for lettuce weed control in hot summer areas. Properties of solarizing films and lettuce crop system may considerably affect weed control and yield response of soil solarization. Different solarizing films, including low-density polyethylene, ethylene-vinyl acetate copolymer, low-density

Vincenzo Candido; Trifone D’Addabbo; Vito Miccolis; Donato Castronuovo

2011-01-01

217

Searching for the origins of arable weeds in the Near East  

Microsoft Academic Search

This short note adds to earlier attempts at identifying arable weeds on late Pleistocene\\/early Holocene sites in the Near\\u000a East. Nineteen potential arable weed taxa that have no known use were selected. The occurrence of these taxa at sites with\\u000a morphologically wild cereals was compared to sites with morphologically domestic cereals. The presumed arable weed taxa were\\u000a as common on

George Willcox

218

Utilization of Stress Tolerant, Weed Suppressive Groundcovers for Low Maintenance Landscape Settings  

Microsoft Academic Search

The recent emphasis on development of alternative, non-chemical weed strategies for landscape and roadside management has\\u000a led to the study and utilization of well-adapted landscape groundcovers, including turfgrass and herbaceous ornamentals that\\u000a can successfully withstand and suppress weed invasion. By selecting groundcovers which exhibit growth characteristics that\\u000a result in consistent interference with weed establishment, one can successfully achieve effective long-term

Leslie A. Weston; Seok Hyun Eom

219

Can feral weeds evolve from cultivated radish (Raphanus sativus, Brassicaceae)?  

PubMed

Cultivated plants that cannot survive on their own often have maladaptive domestication traits. Unharvested crop seeds may generate feral populations, at times causing serious weed problems, but little is known about the evolution of ferality. We explored the potential for cultivated radish, Raphanus sativus, to become feral, given that closely related taxa (e.g., R. raphanistrum and crop-wild hybrids) are well-documented weeds. First, we measured the population growth of five experimental, cultivated, self-seeding radish populations in Michigan, USA, for three generations. Three late-flowering populations went extinct, and two others apparently hybridized with local R. raphanistrum. A common garden experiment showed that the two surviving populations had earlier flowering, smaller root diameters, and greater individual fecundity than did nonhybridized populations. We also used artificial selection to measure the evolutionary potential for earlier flowering. After two generations of strong selection, two of three lineages flowered earlier and produced more seeds than control lineages, but insufficient genetic variation prevented dramatic evolution of crop phenotypes. In summary, it seems unlikely that radishes could spontaneously become feral in our study area without gene flow from R. raphanistrum. Applying these approaches to other cultivated species may provide a better understanding of mechanisms promoting the evolution of feral weeds. PMID:21628205

Campbell, Lesley G; Snow, Allison A

2009-02-01

220

Airborne gamma-ray spectrometer and magnetometer survey: Weed quadrangle, California. Final report  

SciTech Connect

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.

Not Available

1981-05-01

221

Changes in Sensitization Rate to Weed Allergens in Children with Increased Weeds Pollen Counts in Seoul Metropolitan Area  

PubMed Central

The prevalence of allergic diseases in children has increased for several decades. We evaluated the correlation between pollen count of weeds and their sensitization rate in Seoul, 1997-2009. Airborne particles carrying allergens were collected daily from 3 stations around Seoul. Skin prick tests to pollen were performed on children with allergic diseases. Ragweed pollen gradually increased between 1999 and 2005, decreased after 2005 and plateaued until 2009 (peak counts, 67 in 2003, 145 in 2005 and 83 grains/m3/day in 2007). Japanese hop pollen increased between 2002 and 2009 (peak counts, 212 in 2006 and 492 grains/m3/day in 2009). Sensitization rates to weed pollen, especially ragweed and Japanese hop in children with allergic diseases, increased annually (ragweed, 2.2% in 2000 and 2.8% in 2002; Japanese hop, 1.4% in 2000 and 1.9% in 2002). The age for sensitization to pollen gradually became younger since 2000 (4 to 6 yr of age, 3.5% in 1997 and 6.2% in 2009; 7 to 9 yr of age, 4.2% in 1997 and 6.4% in 2009). In conclusion, sensitization rates for weed pollens increase in Korean children given increasing pollen counts of ragweed and Japanese hop.

Kim, Joo-Hwa; Lee, Ha-Baik; Kim, Seong-Won; Kang, Im-Joo; Kook, Myung-Hee; Kim, Bong-Seong; Park, Kang-Seo; Baek, Hey-Sung; Kim, Kyu-Rang; Choi, Young-Jean

2012-01-01

222

Changes in sensitization rate to weed allergens in children with increased weeds pollen counts in Seoul metropolitan area.  

PubMed

The prevalence of allergic diseases in children has increased for several decades. We evaluated the correlation between pollen count of weeds and their sensitization rate in Seoul, 1997-2009. Airborne particles carrying allergens were collected daily from 3 stations around Seoul. Skin prick tests to pollen were performed on children with allergic diseases. Ragweed pollen gradually increased between 1999 and 2005, decreased after 2005 and plateaued until 2009 (peak counts, 67 in 2003, 145 in 2005 and 83 grains/m(3)/day in 2007). Japanese hop pollen increased between 2002 and 2009 (peak counts, 212 in 2006 and 492 grains/m(3)/day in 2009). Sensitization rates to weed pollen, especially ragweed and Japanese hop in children with allergic diseases, increased annually (ragweed, 2.2% in 2000 and 2.8% in 2002; Japanese hop, 1.4% in 2000 and 1.9% in 2002). The age for sensitization to pollen gradually became younger since 2000 (4 to 6 yr of age, 3.5% in 1997 and 6.2% in 2009; 7 to 9 yr of age, 4.2% in 1997 and 6.4% in 2009). In conclusion, sensitization rates for weed pollens increase in Korean children given increasing pollen counts of ragweed and Japanese hop. PMID:22468096

Kim, Joo-Hwa; Oh, Jae-Won; Lee, Ha-Baik; Kim, Seong-Won; Kang, Im-Joo; Kook, Myung-Hee; Kim, Bong-Seong; Park, Kang-Seo; Baek, Hey-Sung; Kim, Kyu-Rang; Choi, Young-Jean

2012-03-21

223

MANIPULATION OF PRECIPITATION AND N ALTERS WEED INVASION OF NORTHERN MIXED-GRASS PRAIRIE  

Technology Transfer Automated Retrieval System (TEKTRAN)

Because many invasive weeds are most successful in high-resource environments, global changes that increase plant resources may exacerbate weed invasion. In the Northern Mixed-Grass Prairie region, which contains the largest remaining expanse of native grassland in North America, changes have been p...

224

WEED SEEDBANK DYNAMICS IN ORGANIC AND CONVENTIONAL LONG-TERM CROPPING SYSTEMS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Weed management is one of the biggest challenges in organic farming. The Farming Systems Project (FSP) in Beltsville, MD, compares five cropping systems, two conventional and three organic. Overall, there has been no long-term increase in the weed seed bank over the first six years. However, there w...

225

Successful Establishment of Exotic Agents for Classical Biological Control of Invasive Weeds in Virginia  

Microsoft Academic Search

Recent research emphasis in the biological control of invasive weeds in Virginia focused on the following weeds: Carduus thoermeri (=nutans) (musk thistle), Carduus acanthoides (plumeless thistle), Cirsium arvense (Canada thistle), Centaurea maculosa (spotted knapweed), and Lythrum salicaria (purple loosestrife). Besides being effective in the control of musk thistle, T. horridus also successfully controls plumeless thistle. Field nurseries of musk thistle

L. T. KOK; T. J. McAVOY; W. T. MAYS

226

WEED CONTROL IN MINT - TWO NEW PRODUCTS SOON TO BE AVAILABLE  

Technology Transfer Automated Retrieval System (TEKTRAN)

Weeds in spearmint and peppermint lower oil yield and quality. Two new herbicides will be available for growers for use in peppermint and spearmint production in the spring of 2004. Both herbicides should be used only on dormant mint prior to the emergence of weeds. Clomazone, a photosynthesis pi...

227

Selection of Fungal Strains for Biological Control of Important Weeds in the Krasnodar Region of Russia  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fungi, collected in different districts of the Krasnodar Region of the Russia Federation, were collected and isolated from diseased weed samples. Weeds sampled included species in the genera Centaurea, Salsola, Vincetoxicum, Carduus, Cirsium, and Echinochloa. Fungal isolates were selected based on ...

228

HERBICIDES-WEEDS: A PRACTICAL APPROACH TO RESISTANCE MANAGEMENT IN POTATO CROPPING SYSTEMS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Herbicides exert a selection pressure on weed populations and weeds that are not controlled may produce seed and give rise to progeny with genetic resistance to the herbicide. Herbicide classification systems based on site/mode of action have been developed and knowing a herbicide’s mode/site of ac...

229

Additive partitioning of arable weed species richness in organic and conventional fields across multiple spatial scales  

Microsoft Academic Search

Organic farming is expected to enhance diversity of arable weeds, and field edges of conventional fields can also harbour diverse arable weed communities. Besides farming practices and field characteristics, the complexity of the surrounding landscape may affect local diversity patterns. In this study, we focused on the relative importance of field edge vs field centre, organic vs conventional management, and

DOREEN GABRIEL; INDRA ROSCHEWITZ; CARSTEN THIES; TEJA TSCHARNTKE

230

INTEGRATING MEASUREMENTS OF SEED AVAILABILITY AND REMOVAL TO ESTIMATE WEED SEED LOSSES DUE TO PREDATION  

Technology Transfer Automated Retrieval System (TEKTRAN)

To fully understand seed predation and as a first step in the search for effective ways to enhance weed seed losses in arable fields, we developed a conceptual model that integrates seed dispersal, seed burial and seed demand, the three processes that describe the dynamics of summer annual weed seed...

231

Annual post-dispersal weed seed predation in contrasting field environments  

Technology Transfer Automated Retrieval System (TEKTRAN)

Interest in weed seed predation as an ecological weed management tactic has led to a growing number of investigations of agronomic and environmental effects on predation rates. Whereas the measurements in most of these studies have taken place at very short time scales, from days to weeks, measureme...

232

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 ...

233

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...

234

Wet Land Paddy Weeding - A Comprehensive Comparative Study from South India  

Microsoft Academic Search

Evaluation of the performance of wet land weeders is inevitable as weed infestation is one of the limiting factors in the rice cultivation in India. The advent of mechanical rice transplanter to Indian agriculture encouraged farmers to use inter-row weeding tools like Rotary weeder, Cono weeder etc. These instruments are now popularising among farmers instead of tedious and low productive

R. Remesan; M. S. Roopesh; N. Remya; P. S. Preman

2007-01-01

235

Hydrogen Cyanide Production Ability by Pseudomonas Fluorescence Bacteria and their Inhibition Potential on Weed Germination  

Microsoft Academic Search

This research was undertaken for the purpose of isolation and purification of indigenous Pseudomonas spp. and evaluating its ability in hydrogen cyanide synthesis and also evaluating the potential of super-strains on seedling growth inhibition in weeds. According to this, the research was carried out in laboratory tests. 136 strains (obtained from rhizosphere soil of 62 weed species) and 27 strains

Shirin Heydari; Parviz Rezvani Moghadam; Seyyed Mehdi Arab

236

The role of water availability on weed-crop interactions in processing tomato for Southern Italy  

Technology Transfer Automated Retrieval System (TEKTRAN)

The aim of this study was to quantify the role of water availability on crop and weed interactions and weed-induced crop losses for processing tomato grown in Southern Italy. Field experiments were carried out during 2008 and 2009, for a two year period. Two levels of water availability (rainfed an...

237

Weeding the Forest Hill Branch of Toronto Public Library by the Slote Method: A Test Case.  

ERIC Educational Resources Information Center

|Describes a two-part book circulation use study conducted to find a simple inexpensive and effective method of weeding a public library branch collection, to determine whether weeding increases circulation, and to compare results with Slote's results. Seven tables, one appendix, and 32 references are provided. (RBF)|

McKee, Penelope

1981-01-01

238

Survey of Weeds Associated to Cultivated Low Yield Pastures in the Northern Region of Pará, Brazil  

Microsoft Academic Search

Pasture for raising cattle has been the major land use in the Amazon region of Brazil. This agricultural practice has caused environmental disturbances associated with deforestation and burning. After five or six years of intensive pasture, the land undergoes degradation due to poor management and high weed infestation. A survey was carried out to identify the main weeds in 0.33

MODESTO JÚNIOR

2001-01-01

239

Air-propelled abrasive grit for postemergence in-row weed control in field corn  

Technology Transfer Automated Retrieval System (TEKTRAN)

Organic growers need additional tools for weed control. A new technique involving abrasive grit propelled by compressed air was tested in field plots. Grit derived from corn cobs was directed at seedlings of summer annual weeds growing at the bases of corn plants when the corn was at differing early...

240

STRATEGIES FOR USE OF PATHOGENS IN WEED BIOLOGICAL CONTROL: SOME LESSONS FROM SIMILAR SYSTEMS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Biological control is an important component in weed management. When pursuing pathogens as a biological control agent, location is an important factor to consider where to search for an effective agent. Although there may be more risks and research to conduct, pathogens isolated from weeds in the...

241

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...

242

Weed control and yield comparisons of glyphosate- and glufosinate-resistant corn grown in rotation  

Technology Transfer Automated Retrieval System (TEKTRAN)

A 6-yr field study was conducted from 2004 to 2009 at Stoneville, MS to examine the effects of rotating glyphosate-resistant and glufosinate-resistant corn (Zea mays L.) under reduced tillage conditions on weed control, soil weed seedbank, and yield. The four rotation systems were glyphosate-resista...

243

Evolution of herbicide resistance in weeds: vertically transmitted fungal endophytes as genetic entities  

Microsoft Academic Search

The appearance of heritable resistance to herbicides in weeds is an evolutionary process driven by human selection. Assuming that spontaneous and random mutations originate herbicide resistance genes, which are selected by selection pressure imposed by herbicides, is the simplest model to understand how this phenomenon appears and increases in weed populations. However, the rate of herbicide resistance evolution is not

Martin M. Vila-Aiub; M. Alejandra Martinez-Ghersa; Claudio M. Ghersa

2003-01-01

244

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...

245

Ten Years of Scentless Chamomile: Prospects for the Biological Control of a Weed of Cultivated Land  

Microsoft Academic Search

In 1988, scentless chamomile (Matricaria perforata = Tripleurospermum perforatum) was proposed as a new target weed for biological control in Canada. Scentless chamomile is mainly a weed of cultivated land, where it reduces crop yield. But it also forms dense, semi-permanent stands in periodically disturbed sites, such as slough margins, field depressions or roadsides, from which seeds spread into adjacent

H. L. HINZ

246

Impacts of organic conservation tillage systems on crops, weeds, and soil quality  

Technology Transfer Automated Retrieval System (TEKTRAN)

Organic farming has been identified as promoting soil quality even though tillage is used for weed suppression. Adopting conservation tillage practices can enhance soil quality in cropping systems where synthetic agrichemicals are used for crop nutrition and weed control. Attempts have been made t...

247

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...

248

Isolates of Diaporthe - Phomopsis from Weeds and Their Effects on Soybeans  

Technology Transfer Automated Retrieval System (TEKTRAN)

Greenhouse and laboratory studies were conducted in 2004 to determine the identity and pathogenicity of Phomopsis longicolla and other Diaporthe/Phomopsis spp. recovered from weed species using DNA sequences, morphology and pathogenicity assays. Among the isolates recovered from eight weed species...

249

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...

250

Real World of Industrial Chemistry: The Challenge of Herbicides for Aquatic Weeds.  

ERIC Educational Resources Information Center

|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)|

Martin, Dean F.; Martin, Barbara B.

1985-01-01

251

Organic weed management: A review of the current UK farmer perspective  

Microsoft Academic Search

In organic systems, farmers, advisors, researchers, and even policy makers, often cite weeds as one of the major constraints to production. This despite the enormous amount of formal research, both conventional and organic, that has been undertaken on weed management. In addition to this a large body of informal knowledge based on farmer experience also exists. In this context this

R. J. Turner; G. Davies; H. Moore; A. C. Grundy; A. Mead

2007-01-01

252

Appropriateness of Non-Destructive Measures of Young Pine Tree Performance in Weeding Experiments  

Microsoft Academic Search

The objective of this work was to compare several commonly used measures of tree performance in three commercially grown pine species (Pinus patula, P. taeda and P. elliottii) during the first growth season in a weeding experiment. Both tree mortality and above-ground tree biomass measures indicated that there was significant tree suppression by weeds for all three species. Using above-ground

N. S. Eccles; J. L. Kritzinger; K. M. Little

1997-01-01

253

Evaluation of row-spacing, seedbed preparation, and weed control options for dryland soybean  

Microsoft Academic Search

Production systems for dryland full season soybean consist of seedbed preparation, planting operations, weed control activities and harvesting operations. Often production system choices are interdependent across seedbed preparation, planting equipment and weed control options. For example, the selection of one system option such as no-till seedbed preparation restricts planting equipment choices. Evaluating production systems requires that a holistic approach be

P. M. Manning; T. C. Keisling; M. P. Popp; L. R. Oliver

2001-01-01

254

Biological Control of Weeds in Mauritius: Past Successes Revisited and Present Challenges  

Microsoft Academic Search

Ten insect species were introduced to control five weeds on the island of Mauritius from 1914 to1982. Eight of these (80%) became established. The biocontrol programs against Opuntia vulgaris, O. tuna and Cordia curassavica were completely successful, with all three target plants now not considered as weeds, and requiring no management other than the ongoing, self-sustaining biological control. Lantana camara

S. V. FOWLER; S. GANESHAN; J. MAUREMOOTOO; Y. MUNGROO

255

Intercropping Leafy Greens and Maize on Weed Infestation, Crop Development, and Yield  

Microsoft Academic Search

Weed control in the tropics accounts for a large proportion of the total effort spent on cultivation. Experiments were conducted to investigate effects of time of establishment of leafy greens on their yields, weed control, and growth and yield of maize (Zea mays L.) in an intercrop. Amaranthus and Celosia were separately established as intercrops with maize on the same

Eyitayo A. Makinde; Olukemi T. Ayoola; Esther A. Makinde

2009-01-01

256

New Weed Control Approaches in Small Grains and Off-Target Movement Challenges  

Microsoft Academic Search

Bromoxynil (Buctril), a contact herbicide, is effective on young seedling weeds. It is less effective on older weeds and must be tank-mixed with other herbicides when larger mustards are present. Therefore, higher volume application and thorough coverage is more important with bromoxynil than with phenoxy herbicides. An advantage of bromoxynil is that it controls fiddleneck. Bromoxynil also is recommended in

Steve Wright; Mick Canevari; Lalo Banuelos; Matt Mills; Anna Brown

257

Yield and Yield Components of Mungbean as Affected by Various Weed Control Methods under Rain-fed Conditions of Pakistan  

Microsoft Academic Search

A field study was conducted at National Agricultural Research Centre (NARC), Islamabad during two crop years (2003 - 04) to determine the effect of different weed control methods on the yield and yield components of mungbean (Vigna radiata L.). In this study different weed control methods (chemical, mechanical, hand-weeding & their integration) were compared for their efficiency to control various

MUHAMMAD RIAZ CHATTHA; MUHAMMAD JAMIL; TAHIRA ZAFAR MAHMOOD

258

Integration of biological control agents with other weed management technologies: Successes from the leafy spurge ( Euphorbia esula) IPM program  

Microsoft Academic Search

An invasive weed can occupy a variety of environments and ecological niches and generally no single control method can be used across all areas the weed is found. Biological control agents integrated with other methods can increase and\\/or improve site-specific weed control, but such combinatorial approaches have not been widely utilized. The successful leafy spurge (Euphorbia esula L.) control program

Rodney G. Lym

2005-01-01

259

Cover crop residue and organic mulches provide weed control during limited-input no-till collard production  

Technology Transfer Automated Retrieval System (TEKTRAN)

Limited input producers may adopt no-till if sufficient weed suppression can be achieved. High-biomass producing cover crops used in conjunction with organic mulches may provide sufficient weed control in no-till vegetable production. Our objective was to quantify weed suppression from a summer co...

260

Effects of seeding rate and poultry litter on weed suppression from a rolled cereal rye cover crop  

Technology Transfer Automated Retrieval System (TEKTRAN)

Growing enough cover crop biomass to adequately suppress weeds is one of the primary challenges in reduced-tillage systems that rely on mulch-based weed suppression. We investigated two approaches to increasing cereal rye biomass for improved weed suppression: (1) increasing soil fertility and (2) i...

261

Volatile Metabolites Controlling Germination in Buried Weed Seeds  

PubMed Central

Velvetleaf (Abutilon theophrasti Medic), morning glory (Ipomoea purpurea [L.] Roth), and wild mustard (Brassica kaber [D.C.] L. C. Wheeler) seeds exhibited decreased germination with increased planting depth in soil. Flushing the soil for 2 minutes each day with air overcame the inhibition. A sealed in vitro system was used to sample the volatile components produced by weed seeds. Inhibition of seed germination was accompanied by decreased O2 levels and production of volatile metabolites identified as acetaldehyde, ethanol, and acetone. The effectiveness of these compounds in reducing germination was dependent on O2 levels.

Holm, Robert E.

1972-01-01

262

Development of a multispectral imagery device devoted to weed detection  

NASA Astrophysics Data System (ADS)

Multispectral imagery is a large domain with number of practical applications: thermography, quality control in industry, food science and agronomy, etc. The main interest is to obtain spectral information of the objects for which reflectance signal can be associated with physical, chemical and/or biological properties. Agronomic applications of multispectral imagery generally involve the acquisition of several images in the wavelengths of visible and near infrared. This paper will first present different kind of multispectral devices used for agronomic issues and will secondly introduce an original multispectral design based on a single CCD. Third, early results obtained for weed detection are presented.

Vioix, Jean-Baptiste; Douzals, Jean-Paul; Truchetet, Frederic; Navar, Pierre

2003-04-01

263

A special vegetation index for the weed detection in sensor based precision agriculture.  

PubMed

Many technologies in precision agriculture (PA) require image analysis and image- processing with weed and background differentiations. The detection of weeds on mulched cropland is one important image-processing task for sensor based precision herbicide applications. The article introduces a special vegetation index, the Difference Index with Red Threshold (DIRT), for the weed detection on mulched croplands. Experimental investigations in weed detection on mulched areas point out that the DIRT performs better than the Normalized Difference Vegetation Index (NDVI). The result of the evaluation with four different decision criteria indicate, that the new DIRT gives the highest reliability in weed/background differentiation on mulched areas. While using the same spectral bands (infrared and red) as the NDVI, the new DIRT is more suitable for weed detection than the other vegetation indices and requires only a small amount of additional calculation power. The new vegetation index DIRT was tested on mulched areas during automatic ratings with a special weed camera system. The test results compare the new DIRT and three other decision criteria: the difference between infrared and red intensity (Diff), the soil-adjusted quotient between infrared and red intensity (Quotient) and the NDVI. The decision criteria were compared with the definition of a worse case decision quality parameter Q, suitable for mulched croplands. Although this new index DIRT needs further testing, the index seems to be a good decision criterion for the weed detection on mulched areas and should also be useful for other image processing applications in precision agriculture. The weed detection hardware and the PC program for the weed image processing were developed with funds from the German Federal Ministry of Education and Research (BMBF). PMID:16917726

Langner, Hans-R; Böttger, Hartmut; Schmidt, Helmut

2006-06-01

264

Population genetic structure of a colonising, triploid weed, Hieracium lepidulum.  

PubMed

Understanding the breeding system and population genetic structure of invasive weed species is important for biocontrol, and contributes to our understanding of the evolutionary processes associated with invasions. Hieracium lepidulum is an invasive weed in New Zealand, colonising a diverse range of habitats including native Nothofagus forest, pine plantations, scrubland and tussock grassland. It is competing with native subalpine and alpine grassland and herbfield vegetation. H. lepidulum is a triploid, diplosporous apomict, so theoretically all seed is clonal, and there is limited potential for the creation of variation through recombination. We used intersimple sequence repeats (ISSRs) to determine the population genetic structure of New Zealand populations of H. lepidulum. ISSR analysis of five populations from two regions in the South Island demonstrated high intrapopulation genotypic diversity, and high interpopulation genetic structuring; PhiST = 0.54 over all five populations. No private alleles were found in any of the five populations, and allelic differentiation was correlated to geographic distance. Cladistic compatibility analysis indicated that both recombination and mutation were important in the creation of genotypic diversity. Our data will contribute to any biocontrol program developed for H. lepidulum. It will also be a baseline data set for future comparisons of genetic structure during the course of H. lepidulum invasions. PMID:14679390

Chapman, H; Robson, B; Pearson, M L

2004-03-01

265

The red queen in the corn: agricultural weeds as models of rapid adaptive evolution.  

PubMed

Weeds are among the greatest pests of agriculture, causing billions of dollars in crop losses each year. As crop field management practices have changed over the past 12?000 years, weeds have adapted in turn to evade human removal. This evolutionary change can be startlingly rapid, making weeds an appealing system to study evolutionary processes that occur over short periods of time. An understanding of how weeds originate and adapt is needed for successful management; however, relatively little emphasis has been placed on genetically characterizing these systems. Here, we review the current literature on agricultural weed origins and their mechanisms of adaptation. Where possible, we have included examples that have been genetically well characterized. Evidence for three possible, non-mutually exclusive weed origins (from wild species, crop-wild hybrids or directly from crops) is discussed with respect to what is known about the microevolutionary signatures that result from these processes. We also discuss what is known about the genetic basis of adaptive traits in weeds and the range of genetic mechanisms that are responsible. With a better understanding of genetic mechanisms underlying adaptation in weedy species, we can address the more general process of adaptive evolution and what can be expected as we continue to apply selective pressures in agroecosystems around the world. PMID:23188175

Vigueira, C C; Olsen, K M; Caicedo, A L

2012-11-28

266

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

PubMed Central

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.

Andujar, Dionisio; Ribeiro, Angela; Fernandez-Quintanilla, Cesar; Dorado, Jose

2011-01-01

267

Weed control in potatoes with 2,4-D  

Microsoft Academic Search

Summary  \\u000a \\u000a \\u000a \\u000a (1.) \\u000a \\u000a 2,4-D spray, applied at the rate of 1.2 pounds of the free acid per acre, gave excellent control of the annual broad-leaved\\u000a weeds in potatoes.\\u000a \\u000a \\u000a \\u000a \\u000a (2.) \\u000a \\u000a No detrimental effect on yield or quality of tubers of the Katahdin variety was found in either 1946 or 1947.\\u000a \\u000a \\u000a \\u000a \\u000a (3.) \\u000a \\u000a A difference in varietal and seasonal reaction to 2,4-D was apparent.

M. R. Thompson; R. W. Shuel

1948-01-01

268

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

Code of Federal Regulations, 2013 CFR

...plant taxon should be listed as a noxious weed: (a) Identification of the taxon. (1) The taxon's scientific name and author; (2) Common synonyms; (3) Botanical classification; (4) Common names; (5) Summary of life history;...

2013-01-01

269

SCREENING OF WEED SPECIES FOR REACTION TO SCLEROTINIA MINOR AND SCLEROTIUM ROLFSII  

Technology Transfer Automated Retrieval System (TEKTRAN)

Sclerotium rolfsii and Sclerotinia minor have wide host ranges including 500 and 222 plant species, respectively. Three-week-old plants of sixteen weed species (Citronmelon, Crownbeard, Cypressvine morningglory, Eclipta, Hemp sesbania, Ivyleaf morningglory, Jimsonweed, Kochia, Pitted morningglory, ...

270

7 CFR 205.206 - Crop pest, weed, and disease management practice standard.  

Code of Federal Regulations, 2010 CFR

...enhance crop health, including selection of plant species and varieties with regard to suitability to site-specific conditions and resistance to prevalent pests, weeds, and diseases. (b) Pest problems may be controlled through...

2009-01-01

271

7 CFR 205.206 - Crop pest, weed, and disease management practice standard.  

Code of Federal Regulations, 2013 CFR

...Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) ORGANIC FOODS PRODUCTION ACT PROVISIONS NATIONAL ORGANIC PROGRAM Organic Production and Handling Requirements § 205.206 Crop pest, weed, and...

2013-01-01

272

Idaho's 10 Year Strategic Plan for Biological Control of Noxious and Invasive Weeds 2008-2018.  

National Technical Information Service (NTIS)

To facilitate the meaningful incorporation of biological control into long term integrated weed management throughout the State of Idaho. Biological control, or the use of an introduced organism to control another introduced organism, is one component of ...

2008-01-01

273

Biological Control of Weeds Joe Balciunas Research Report (January 2001 through March 2002).  

National Technical Information Service (NTIS)

Widespread exotic pests are obvious targets for classical (importative) biological control, which attempts to re-associate an exotic pest with carefully selected and screened natural enemies from its native range. Potential biocontrol agents for weeds und...

2002-01-01

274

BRAZILIAN PEPPERTREE SEED CHALCID: MEGASTIGMUS TRANSVAALENSIS WASP WAGES WAR ON WIDESPREAD WEED  

Technology Transfer Automated Retrieval System (TEKTRAN)

An introduced torymid wasp, Megastigmus transvaalensis, from South Africa was recovered in Florida from drupes of the terrestrial weed Brazilian peppertree Schinus terebinthifolius. Collections of S. terebinthifolius drupes in Florida indicated that M. transvaalensis was present at 23 counties surv...

275

Loss of glyphosate efficacy: a changing weed spectrum in Georgia cotton  

Technology Transfer Automated Retrieval System (TEKTRAN)

Introduction of glyphosate resistance into crops through genetic modification has revolutionized crop protection. Glyphosate, the proverbial silver bullet, is a broad spectrum herbicide with favorable environmental characteristics and effective broad-spectrum weed control that has greatly improved ...

276

Production of Reproductively Limited Grass Carp for Biological Control of Aquatic Weeds.  

National Technical Information Service (NTIS)

The need for a biological aquatic weed control is increasingly evident as the cost-effectiveness and environmental concerns make chemical treatment less desirable. The grass carp, a native fish of Southeast Asia is an effective consumer of aquatic macroph...

W. L. Shelton G. L. Jensen

1979-01-01

277

Utilizing Brassicaceae seed meal as a soil amendment to suppress weed and soil borne pathogens  

Technology Transfer Automated Retrieval System (TEKTRAN)

Increased demand for organic and sustainable agricultural production systems and restrictions on registration and use of toxic synthetic pesticides have generated demand for effective non-synthetic and environmentally friendly alternative weed and pathogen management strategies. Lack of effective a...

278

Dicamba resistance: enlarging and preserving biotechnology-based weed management strategies.  

PubMed

The advent of biotechnology-derived, herbicide-resistant crops has revolutionized farming practices in many countries. Facile, highly effective, environmentally sound, and profitable weed control methods have been rapidly adopted by crop producers who value the benefits associated with biotechnology-derived weed management traits. But a rapid rise in the populations of several troublesome weeds that are tolerant or resistant to herbicides currently used in conjunction with herbicide-resistant crops may signify that the useful lifetime of these economically important weed management traits will be cut short. We describe the development of soybean and other broadleaf plant species resistant to dicamba, a widely used, inexpensive, and environmentally safe herbicide. The dicamba resistance technology will augment current herbicide resistance technologies and extend their effective lifetime. Attributes of both nuclear- and chloroplast-encoded dicamba resistance genes that affect the potency and expected durability of the herbicide resistance trait are examined. PMID:17525337

Behrens, Mark R; Mutlu, Nedim; Chakraborty, Sarbani; Dumitru, Razvan; Jiang, Wen Zhi; Lavallee, Bradley J; Herman, Patricia L; Clemente, Thomas E; Weeks, Donald P

2007-05-25

279

Automatic identification of crop and weed species with chlorophyll fluorescence induction curves  

Microsoft Academic Search

Automatic identification of crop and weed species is required for many precision farming practices. The use of chlorophyll\\u000a fluorescence fingerprinting for identification of maize and barley among six weed species was tested. The plants were grown\\u000a in outdoor pots and the fluorescence measurements were done in variable natural conditions. The measurement protocol consisted\\u000a of 1 s of shading followed by two

Esa Tyystjärvi; Michael Nørremark; Heta Mattila; Mika Keränen; Marja Hakala-Yatkin; Carl-Otto Ottosen; Eva Rosenqvist

2011-01-01

280

Evaluating plant pathogens for biological control of weeds: an alternative view of pest risk assessment  

Microsoft Academic Search

Biological control of weeds is still a relatively new field in plant pathology, in which, instead of trying to keep out exotic\\u000a plant pathogens or to contain indigenous ones, they are actively being exploited in weed management, particularly for alien\\u000a invasives. Two broad approaches can be distinguished, although these are not necessarily mutually exclusive: classical or\\u000a inoculative biological control, involving

Harry C. Evans

2000-01-01

281

The Potential Benefits of Weeds with Reference to Small Holder Agriculture in Africa  

Microsoft Academic Search

Weed control is one of the most important crop protection activities undertaken in both intensive and low-input farming systems. However, even under intensive systems, crop protection which is less dependent on pesticides may require that weeds be managed to obtain a balance between crop and non-crop vegetation to encourage an increase in natural enemies of crop pests. In the low-input

R. J. Hillocks

1998-01-01

282

Effects of Weed Resistance Concerns and Resistance Management Practices on the Value of Roundup Ready® Crops  

Microsoft Academic Search

This study estimates grower benefits of Roundup-Ready® (RR) weed management programs and how weed resistance concerns and resistance management practices affect those benefits. Direct survey methods were used to elicit grower valuation of pecuniary and non-pecuniary benefits. We illustrate a hedonic strategy combined with principal component analysis to address part-whole bias present in previous assessments of non-pecuniary benefits of RR

T. M. Hurley; P. D. Mitchell; G. Frisvold

283

Herbaceous weed control in conifer plantations with hexazinone and nitrogen formulations  

Microsoft Academic Search

In order to determine if herbicide efficacy is affected by nitrogen fertilizer, the influence of different nitrogen fertilizers applied in different combinations with hexazinone formulations were evaluated on herbaceous weed communities. Field studies comparing three application methods in conifer plantations showed greatest reduction in total weed cover with a co-granular formulation of hexazinone and triamino-s-triazine. Slightly less control was achieved

Diane E. White; Laura Witherspoon-Joos; Michael Newton

1990-01-01

284

Cadmium accumulation in the shoots and roots of 93 weed species  

Microsoft Academic Search

The present study was conducted to find useful weed species for cadmium (Cd) phytoremediation. Ninety-three weed species and eight crop species were grown for 2 months in pots containing sandy loam soil with 3 mg Cd kg dry weight (DW). The Cd concentrations in the shoots and roots of all species were determined by inductively coupled plasma optical emission spectroscopy and atomic absorption spectrometry.

Takuya Abe; Motohiro Fukami; Masaru Ogasawara

2008-01-01

285

Weed resistance development and management in herbicide-tolerant crops: experiences from the USA  

Microsoft Academic Search

The evolution of weeds in USA agroecosystems predates herbicide tolerant (HT) crops by several decades. However, given the\\u000a unprecedented adoption of genetically engineered (GE) HT crops, particularly in maize, cotton and soybean and the concomitant\\u000a use of glyphosate, the evolution of glyphosate-resistant (GR) biotypes of agronomic important weeds now represents a significant\\u000a threat to the sustainability of the GE HT

Micheal D. K. Owen

2011-01-01

286

Effects of weed management practices on orchard soil biological and fertility properties in southeastern China  

Microsoft Academic Search

Weed management practices on soil biological and fertility properties were studied in a subtropical citrus orchard situated at Changshan County (28°54?N, 118°30?E) in Zhejiang Province, China. Three weed management practices were chemical control plus tillage (herbicide), tillage alone (plowed) and mowing plus tillage (mowed). No significant differences in microbial biomass carbon (MBC), soil organic matter (SOM) or total nitrogen (TN)

Yisong Yang; Han Wang; Jianjun Tang; Xin Chen

2007-01-01

287

Potential biological control of weeds in rice fields by allelopathy of dwarf lilyturf plants  

Microsoft Academic Search

Dwarf lilyturf (Ophiopogonjaponicus Ker-Gawl), a medicinal plant, hasbeen used for sore throat therapy andinhibition of physiological thirst sinceancient times. Experimental studies wereconducted to determine the allelopathic effectsof dwarf lilyturf plants on germination andgrowth of three main weed species, viz.,barnyardgrass (Echinochloa crusgalli L.),monchoria (Monocharia vaginalis P.) andsmallflower umbrella (Cyperus difformisL.), in rice production and on emergence andgrowth of weeds in rice

Dongzhi Lin; Eiji Tsuzuki; Yanjun Dong; H. Terao; T. D. Xuan

2004-01-01

288

Screening techniques and sources of resistance against parasitic weeds in grain legumes  

Microsoft Academic Search

Summary  A number of parasitic plants have become weeds, posing severe constraints to major crops including grain legumes. Breeding\\u000a for resistance is acknowledged as the major component of an integrated control strategy. However, resistance against most\\u000a parasitic weeds is difficult to access, scarce, of complex nature and of low heritability, making breeding for resistance\\u000a a difficult task. As an exception, resistance

Diego Rubiales; Alejandro Pérez-de-Luque; Mónica Fernández-Aparico; Josefina C. Sillero; Belén Román; Mohamed Kharrat; Shaban Khalil; Daniel M. Joel; Charlie Riches

2006-01-01

289

Host-plant selectivity of rhizobacteria in a crop/weed model system.  

PubMed

Belowground microorganisms are known to influence plants' performance by altering the soil environment. Plant pathogens such as cyanide-producing strains of the rhizobacterium Pseudomonas may show strong host-plant selectivity. We analyzed interactions between different host plants and Pseudomonas strains and tested if these can be linked to the cyanide sensitivity of host plants, the cyanide production of bacterial strains or the plant identity from which strains had been isolated. Eight strains (four cyanide producing) were isolated from roots of four weed species and then re-inoculated on the four weed and two additional crop species. Bacterial strain composition varied strongly among the four weed species. Although all six plant species showed different reductions in root growth when cyanide was artificially applied to seedlings, they were generally not negatively affected by inoculation with cyanide-producing bacterial strains. We found a highly significant plant species x bacterial strain interaction. Partitioning this interaction into contrasts showed that it was entirely due to a strongly negative effect of a bacterial strain (Pseudomonas kilonensis/brassicacearum, isolated from Galium mollugo) on Echinochloa crus-galli. This exotic weed may not have become adapted to the bacterial strain isolated from a native weed. Our findings suggest that host-specific rhizobacteria hold some promise as biological weed-control agents. PMID:17786217

Zeller, Simon L; Brandl, Helmut; Schmid, Bernhard

2007-09-05

290

Host-Plant Selectivity of Rhizobacteria in a Crop/Weed Model System  

PubMed Central

Belowground microorganisms are known to influence plants' performance by altering the soil environment. Plant pathogens such as cyanide-producing strains of the rhizobacterium Pseudomonas may show strong host-plant selectivity. We analyzed interactions between different host plants and Pseudomonas strains and tested if these can be linked to the cyanide sensitivity of host plants, the cyanide production of bacterial strains or the plant identity from which strains had been isolated. Eight strains (four cyanide producing) were isolated from roots of four weed species and then re-inoculated on the four weed and two additional crop species. Bacterial strain composition varied strongly among the four weed species. Although all six plant species showed different reductions in root growth when cyanide was artificially applied to seedlings, they were generally not negatively affected by inoculation with cyanide-producing bacterial strains. We found a highly significant plant species x bacterial strain interaction. Partitioning this interaction into contrasts showed that it was entirely due to a strongly negative effect of a bacterial strain (Pseudomonas kilonensis/brassicacearum, isolated from Galium mollugo) on Echinochloa crus-galli. This exotic weed may not have become adapted to the bacterial strain isolated from a native weed. Our findings suggest that host-specific rhizobacteria hold some promise as biological weed-control agents.

Zeller, Simon L.; Brandl, Helmut; Schmid, Bernhard

2007-01-01

291

Weed Mapping in Early-Season Maize Fields Using Object-Based Analysis of Unmanned Aerial Vehicle (UAV) Images.  

PubMed

The use of remote imagery captured by unmanned aerial vehicles (UAV) has tremendous potential for designing detailed site-specific weed control treatments in early post-emergence, which have not possible previously with conventional airborne or satellite images. A robust and entirely automatic object-based image analysis (OBIA) procedure was developed on a series of UAV images using a six-band multispectral camera (visible and near-infrared range) with the ultimate objective of generating a weed map in an experimental maize field in Spain. The OBIA procedure combines several contextual, hierarchical and object-based features and consists of three consecutive phases: 1) classification of crop rows by application of a dynamic and auto-adaptive classification approach, 2) discrimination of crops and weeds on the basis of their relative positions with reference to the crop rows, and 3) generation of a weed infestation map in a grid structure. The estimation of weed coverage from the image analysis yielded satisfactory results. The relationship of estimated versus observed weed densities had a coefficient of determination of r(2)=0.89 and a root mean square error of 0.02. A map of three categories of weed coverage was produced with 86% of overall accuracy. In the experimental field, the area free of weeds was 23%, and the area with low weed coverage (<5% weeds) was 47%, which indicated a high potential for reducing herbicide application or other weed operations. The OBIA procedure computes multiple data and statistics derived from the classification outputs, which permits calculation of herbicide requirements and estimation of the overall cost of weed management operations in advance. PMID:24146963

Peña, José Manuel; Torres-Sánchez, Jorge; de Castro, Ana Isabel; Kelly, Maggi; López-Granados, Francisca

2013-10-11

292

Prospects for the Management of Invasive Alien Weeds Using Co-Evolved Fungal Pathogens: A Latin American Perspective  

Microsoft Academic Search

Invasive alien weeds pose a serious threat to the biodiversity of natural ecosystems and a significant constraint to agricultural\\u000a production worldwide. The use of co-evolved natural enemies, a strategy referred to as classical biological control (CBC),\\u000a has proven to be a potentially efficacious, cost-effective, and safe option for the management of alien weeds. An analysis\\u000a of CBC of invasive weeds

Carol A. Ellison; Robert W. Barreto

2004-01-01

293

Weed seeds as nutritional resources for soil Ascomycota and characterization of specific associations between plant and fungal species  

Microsoft Academic Search

Current interest in biological-based management of weed seed banks in agriculture furthers the need to understand how microorganisms\\u000a affect seed fate in soil. Many annual weeds produce seeds in high abundance; their dispersal presenting ready opportunity\\u000a for interactions with soil-borne microorganisms. In this study, we investigated seeds of four common broadleaf weeds, velvetleaf\\u000a (Abutilon theophrasti), woolly cupgrass (Eriochloa villosa), Pennsylvania

Joanne C. Chee-Sanford

2008-01-01

294

Adaptation to flooding during emergence and seedling growth in rice and weeds, and implications for crop establishment  

PubMed Central

Background and aims Direct seeding of rice is being adopted in rainfed and irrigated lowland ecosystems because it reduces labour costs in addition to other benefits. However, early flooding due to uneven fields or rainfall slows down seed germination and hinders crop establishment. Conversely, early flooding helps suppress weeds and reduces the costs of manual weeding and/or dependence on herbicides; however, numerous weed species are adapted to lowlands and present challenges for the use of flooding to control weeds. Advancing knowledge on the mechanisms of tolerance of flooding during germination and early growth in rice and weeds could facilitate the development of improved rice varieties and effective weed management practices for direct-seeded rice. Principal results Rice genotypes with a greater ability to germinate and establish in flooded soils were identified, providing opportunities to develop varieties suitable for direct seeding in flooded soils. Tolerance of flooding in these genotypes was mostly attributed to traits associated with better ability to mobilize stored carbohydrates and anaerobic metabolism. Limited studies were undertaken in weeds associated with lowland rice systems. Remaining studies compared rice and weeds and related weed species such as Echinochloa crus-galli and E. colona or compared ecotypes of the same species of Cyperus rotundus adapted to either aerobic or flooded soils. Conclusions Tolerant weeds and rice genotypes mostly developed similar adaptive traits that allow them to establish in flooded fields, including the ability to germinate and elongate faster under hypoxia, mobilize stored starch reserves and generate energy through fermentation pathways. Remarkably, some weeds developed additional traits such as larger storage tubers that enlarge further in deeper flooded soils (C. rotundus). Unravelling the mechanisms involved in adaptation to flooding will help design management options that will allow tolerant rice genotypes to adequately establish in flooded soils while simultaneously suppressing weeds.

Ismail, Abdelbagi M.; Johnson, David E.; Ella, Evangelina S.; Vergara, Georgina V.; Baltazar, Aurora M.

2012-01-01

295

Weed Mapping in Early-Season Maize Fields Using Object-Based Analysis of Unmanned Aerial Vehicle (UAV) Images  

PubMed Central

The use of remote imagery captured by unmanned aerial vehicles (UAV) has tremendous potential for designing detailed site-specific weed control treatments in early post-emergence, which have not possible previously with conventional airborne or satellite images. A robust and entirely automatic object-based image analysis (OBIA) procedure was developed on a series of UAV images using a six-band multispectral camera (visible and near-infrared range) with the ultimate objective of generating a weed map in an experimental maize field in Spain. The OBIA procedure combines several contextual, hierarchical and object-based features and consists of three consecutive phases: 1) classification of crop rows by application of a dynamic and auto-adaptive classification approach, 2) discrimination of crops and weeds on the basis of their relative positions with reference to the crop rows, and 3) generation of a weed infestation map in a grid structure. The estimation of weed coverage from the image analysis yielded satisfactory results. The relationship of estimated versus observed weed densities had a coefficient of determination of r2=0.89 and a root mean square error of 0.02. A map of three categories of weed coverage was produced with 86% of overall accuracy. In the experimental field, the area free of weeds was 23%, and the area with low weed coverage (<5% weeds) was 47%, which indicated a high potential for reducing herbicide application or other weed operations. The OBIA procedure computes multiple data and statistics derived from the classification outputs, which permits calculation of herbicide requirements and estimation of the overall cost of weed management operations in advance.

Pena, Jose Manuel; Torres-Sanchez, Jorge; de Castro, Ana Isabel; Kelly, Maggi; Lopez-Granados, Francisca

2013-01-01

296

Experimental Transmission of Pospiviroid Populations to Weed Species Characteristic of Potato and Hop Fields?  

PubMed Central

Weed plants characteristic for potato and hop fields have not been considered in the past as potential hosts that could transmit and lead to spreading of potato spindle tuber (PSTVd) and hop stunt (HSVd) viroids, respectively. To gain insight into this problem, we biolistically inoculated these weed plants with viroid populations either as RNA or as cDNA. New potential viroid host species, collected in central Europe, were discovered. From 12 weed species characteristic for potato fields, high viroid levels, detectable by molecular hybridization, were maintained after both RNA and DNA transfers in Chamomilla reculita and Anthemis arvensis. Low viroid levels, detectable by reverse transcription-PCR (RT-PCR) only, were maintained after plant inoculations with cDNA in Veronica argensis and Amaranthus retroflexus. In these two species PSTVd concentrations were 105 and 103 times, respectively, lower than in tomato as estimated by real-time PCR. From 14 weeds characteristic for hop fields, high HSVd levels were detected in Galinsoga ciliata after both RNA and DNA transfers. HSVd was found, however, not to be transmissible by seeds of this weed species. Traces of HSVd were detectable by RT-PCR in HSVd-cDNA-inoculated Amaranthus retroflexus. Characteristic monomeric (+)-circular and linear viroid RNAs were present in extracts from weed species propagating viroids to high levels, indicating regular replication, processing, and circularization of viroid RNA in these weed species. Sequence analyses of PSTVd progenies propagated in C. reculita and A. arvensis showed a wide spectrum of variants related to various strains, from mild to lethal variants; the sequence variants isolated from A. retroflexus and V. argensis exhibited similarity or identity to the superlethal AS1 viroid variant. All HSVd clones from G. ciliata corresponded to a HSVdg variant, which is strongly pathogenic for European hops.

Matousek, J.; Orctova, L.; Ptacek, J.; Patzak, J.; Dedic, P.; Steger, G.; Riesner, D.

2007-01-01

297

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

PubMed

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 reservoirs may also interrupt hydrochory, the downstream flow of seeds and clonal fragments. We thus conclude that with some operational patterns, dams and reservoirs can impede the downstream expansion of riparian weeds. PMID:20945766

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

2010-09-01

298

RMRS(Rocky Moutain Research Station) Weed Biocontrol Research: Past Accomplishments, Current Status, and Future Challenges. Accomplishments Report Fiscal Years 2007-2011.  

National Technical Information Service (NTIS)

This report has the primary objective of documenting the accomplishments of weed biocontrol researchers at the Rocky Mountain Research Station (RMRS) over the last five fiscal years. RMRS weed biocontrol scientists perform basic and applied research direc...

2011-01-01

299

Reviewer's Manual for the Technical Advisory Group for Biological Control Agents of Weeds. Guidelines for Evaluating the Safety of Candidate Biological Control Agents.  

National Technical Information Service (NTIS)

Biological control is usually defined as using natural organisms to control weeds, insect, or pathogen pests. Classical biological control of weeds consists of returning to the native range of the week, identifying its complex of natural enemies, testing ...

2003-01-01

300

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...

301

Evaluation of the Upland Weed Control Potentiality of Green Tea Waste - Rice Bran Compost and Its Effect on Spinach Growth  

Microsoft Academic Search

This study evaluated the upland weed control potentiality, germination inhibition ability and growth suppression efficiency of the five combinations of green tea waste - rice bran compost (GRC). GRC was prepared by mixing green tea waste and rice bran at five ratios, and allowed to decompose for 5 mo. Application of GRC suppressed weed growth up to 93.4% in number

M. A. I. Khan; K. Ueno; S. Horimoto; F. Komai; K. Tanaka; Y. Ono

302

Predation by phytoseiid mites on Tetranychus lintearius (Acari: Tetranychidae), an established weed biological control agent of gorse ( Ulex europaeus)  

Microsoft Academic Search

Development of trophic relationships among introduced biological control agents and native (or introduced) parasitoids, predators, or pathogens can interfere with successful establishment, spread, and ecological impact on the target pest. For the introduced weed biological control agent Tetranychus lintearius (Dufor), we assessed predator acquisition, the ability of these predators to survive and reproduce when held with the weed biological control

P. D. Pratt; E. M. Coombs; B. A. Croftc

2003-01-01

303

Conservation headlands for rare arable weeds: The effects of fertilizer application and light penetration on plant growth  

Microsoft Academic Search

In addition to promoting agricultural wildlife in general, conservation headlands may be a method of providing a refuge to endangered arable weeds. The conservation headland technique excludes herbicide and insecticide use in the outer 2–3 m of the arable field, but does not restrict fertilizer inputs. We studied the effects of fertilizer application on the weed vegetation in relation to

David Kleijn; Leonie A. C. van der Voort

1997-01-01

304

HOST RANGE OF DELETERIOUS RHIZOBACTERIA FOR BIOLOGICAL CONTROL OF WEEDS OF CROPPING SYSTEMS IN AUSTRALIA AND SOUTH KOREA  

Technology Transfer Automated Retrieval System (TEKTRAN)

Deleterious rhizobacteria (DRB) as biocontrol agents for weeds have received considerable attention in developing alternative weed management for reducing herbicide use and intensive tillage. The specificity of growth-suppressive rhizobacteria must be determined on a wide range of plant species prio...

305

THE EFFECT OF VARIOUS LANDSCAPE WEED CONTROL MEASURES ON SOIL MOISTURE AND TEMPERATURE, AND TREE ROOT GROWTH  

Microsoft Academic Search

Seven landscape weed control measures (five landscape fabrics\\/films, black plastic, and a preemergence herbicide, each with and without mulch) were compared with bare soil to determine their affect on soil moisture and temperature. When mulched, there were no differences during any season. When unmulched, landscape fabrics\\/films varied in their effects. Soil moisture in unmulched plots decreased as weed growth increased.

B. L. Appleton; J. F. Derr; B. B. Ross

1987-01-01

306

Predicting and mitigating weed invasions to restore natural post-fire succession in Mesa Verde National Park, Colorado, USA  

Microsoft Academic Search

Six large wildfires have burned in Mesa Verde National Park during the last 15 years, and extensive portions of burns were invaded by non-native plant species. The most threatening weed species include Carduus nutans, Cirsium arvense, and Bromus tectorum, and if untreated, they persist at least 13 years. We investigated patterns of weed distribution to identify plant communities most vulnerable

M. Lisa FloydA; David HannaA; William H. RommeB; Timothy E. CrewsA

2006-01-01

307

Interaction effects of two biological control organisms on resistant and susceptible weed biotypes of Chondrilla juncea in western North America  

Microsoft Academic Search

Interactions between natural enemy species may modify their net effect on host plants, but little research has been done to examine how plant resistance influences species interactions in biological weed control. We performed common garden experiments with clonal accessions of Chondrilla juncea to compare a rust-susceptible weed biotype with a rust-resistant biotype, both of which are invasive in western North

Donald M. Campanella; Peter B. McEvoy; Christopher C. Mundt

2009-01-01

308

EVALUATION OF TWO METHODS OF THERMAL WEED CONTROL IN FRUIT TREE ORCHARDS, PESTICIDE SPECIAL STUDY, COLORADO STATE UNIVERSITY  

EPA Science Inventory

Research Objectives: 1) Compare the efficiency of two different types of thermal flamers: a direct flamer (Red Dragon, Inc., LaCrosse, Kansas) and a prototype infrared weed flamer (Sunburst, Inc., Eugene Oregon) in controlling weed populations in an apple orchard. 2) Determine ...

309

An Economic Evaluation of Research into the Improved Management of the Annual Grass Weed Vulpia in Temperate Pastures in South-Eastern Australia  

Microsoft Academic Search

NSW Agriculture has a history of research investment in managing weed problems in the temperate pasture areas. One focus of that research has been on the development of improved management practices for the major annual grass weed vulpia. Recent surveys have found that weeds comprised up to 80% of pasture biomass in some temperate areas and that typical vulpia contents

David T. Vere; Randall E. Jones; Peter Dowling

2004-01-01

310

DISTRIBUCIONES ESPACIALES DE MALEZAS Y RENDIMIENTO DE MAÍZ EN LABRANZA REDUCIDA Y CONVENCIONAL WEED AND CORN YIELD SPATIAL DISTRIBUTIONS IN REDUCED AND CONVENTIONAL TILLAGE  

Microsoft Academic Search

Little is known about the spatial structure of weeds and of the corn yield distribution because the analysis of these variables with conventional statistical methods assume that both weed population and corn grain yield are homogeneously distributed within cropped fields. In this research, geostatistical techniques were used to de- scribe and map the distribution of weeds and corn yield in

Mario Domingo Amador-Ramírez; J. Santos Escobedo-Rosales

311

Policies for the management of weeds in natural ecosystems: the case of scotch broom ( Cytisus scoparius, L .) in an Australian national park  

Microsoft Academic Search

Environmental weeds are plants that invade natural ecosystems and present a serious threat to conservation of nature. Environmental weeds have been implicated in the extinction of several indigenous plant species, and they also threaten ecosystem stability and functional complexity. Historically, emphasis in weed control in Australian national parks has been placed on chemicals, manual pulling of small plants, excluding tourists

Doreen I. S. Odom; Oscar J. Cacho; J. A. Sinden; Garry R. Griffith

2003-01-01

312

GREEN MANURE WEED CONTROL IN POTATO PRODUCTION? Presented during the workshop on CROPPING SEQUENCE AND ROTATION: IMPACT ON POTATO PRODUCTION AND SOIL CONDITION  

Microsoft Academic Search

Including a green manure within the cropping system can reduce weed populations and associated costs of control. Studies to determine the effectiveness of green manures for weed control or suppression were discussed during the Cropping Sequence and Rotations Workshop as follows: Boydston and Vaughn (2002) evaluated alternative weed management systems in potato, including green manures. This study was conducted in

Pamela J. S. Hutchinson

313

Weed control and yield are improved when glyphosate is preceded by a residual herbicide in glyphosate-tolerant maize ( Zea mays)  

Microsoft Academic Search

In glyphosate-tolerant maize, a delay in glyphosate application may be required to ensure late germinating weeds do not reach reproductive maturity. Alternatively, full season weed control may be achieved by frequent applications of glyphosate throughout the growing season. Another approach that may improve weed control and aid in the stewardship of glyphosate use is to apply a pre-emergence residual herbicide

Robert E. Nurse; Clarence J. Swanton; François Tardif; Peter H. Sikkema

2006-01-01

314

[Controlling effects of multiple species coexistence on rice diseases, pests and weeds in paddy field ecosystem].  

PubMed

Establishing a species-diversified cropping system to control crop diseases, insect pests and weeds is an important approach to sustainable agricultural development. This paper reviewed the researches on paddy field species-diversified cropping systems at home and abroad, and discussed the controlling effects and mechanisms of multiple species coexistence on rice diseases, pests and weeds control. The multiple species coexistence models such as rice-fish, rice-duck, rice-azolla-fish and rice-azolla-duck had effective controlling effects on Thanatephorus cucumeris (Frank) Donk, Nilaparata lugens Stal, Chaphalocrocis medinalis Gueneeand, and weeds. Other models like intercropping rice with Zizania caduciflora L. and with other wetland crops also had effective effects in controlling the occurrence and spread of Pyricularia grisea. It was suggested that further studies should be strengthened from the viewpoints of crop culture, molecular biology, and chemical ecolo- PMID:17650871

Wang, Han; Tang, Jian-jun; Xie, Jian; Chen, Xin

2007-05-01

315

Chemigation for Control of Black Shank-Root-knot Complex and Weeds in Tobacco  

PubMed Central

Tank mixes of a fungicide (metalaxyl) and a nematicide (fenamiphos) with herbicides (isopropalin or pendimethalin) and an insecticide (chlorpyrifos) were applied by soil incorporation or irrigation to control the black shank-root knot complex and weeds on four tobacco cultivars. The disease complex was more severe on cultivars McNair 944, NC-2326, and K-326 than on Speight G-70. The disease complex was reduced (P ? 0.05) on all cultivars with the pesticide combinations containing metalaxyl + fenamiphos. On most cultivars, percentage disease, disease index, root-gall index, yield, and weed control did not differ (P ? 0.05) between the tank mixes containing isopropalin or pendimethalin or among methods of application. Generally, the most effective method of treatment application for control of the disease complex and weeds was preplant incorporated followed by postplant irrigation and preplant irrigation.

Johnson, A. W.; Csinos, A. S.; Golden, A. M.; Glaze, N. C.

1992-01-01

316

Allelopathic effects of weeds extracts against seed germination of some plants.  

PubMed

This study investigated the allelopathic effects of various weeds extracts on seed germination of 11 crop species. Most of the weed extracts tested had inhibitory effects on seed germination of common bean, tomato, pepper, squash, onion, barley, wheat, and corn at different application rates as compared with the 10% acetone control. Chickpea seed germination was inhibited by extracts of Solanum nigrum L., Chenopodium album L., and Matricaria chamomilla L. (10%, 20% and 22.5%, respectively) at the end of 21 day incubation period. However, Glycyrrhiza glabra L., Sorghum halepense (L.) Pers., and Reseda lutea L. extracts stimulated chickpea seed germination at the rates of 95%, 94%, and 93%, respectively, compared to control. It was concluded that some of the weed extracts tested in this study could be used as inhibitor while others could be used as stimulator for the crops. PMID:16161968

Kadioglu, Izzet; Yanar, Yusuf; Asav, Unal

2005-04-01

317

Wavelet transform to discriminate between crop and weed in agronomic images  

NASA Astrophysics Data System (ADS)

In precision agriculture, the reduction of herbicide applications requires an accurate detection of weed patches. From image detection, to quantify weed infestations, it would be necessary to identify crop rows from line detection algorithm and to discriminate weed from crop. Our laboratory developed several methods for line detection based on Hough Transform, double Hough Transform or Gabor filtering. The Hough Transform is well adapted to image affected by perspective deformations but the computation burden is heavy and on-line applications are hardly handled. To lighten this problem, we have used a Gabor filter to enhance the crop rows present into the image but, if this method is robust with parallel crop rows (without perspective distortions), it implies to deform image with an inverse projection matrix to be applied in the case of an embedded camera. We propose, in order to implement a filter in the scale / space domain, to use a discrete dyadic wavelet transform. Thus, we can extract the vertical details contained in various parts of the image from different levels of resolution. Each vertical detail level kept allows to enhance the crop rows in a specific part of the initial image. The combination of these details enable us to discriminate crop from weeds with a simple logical operation. This spatial method, thanks to the fast wavelet transform algorithm, can be easily implemented for a real time application and it leads to better results than those obtained from Gabor filtering. For this method, the weed infestation rate is estimated and the performance are compared to those given by other methods. A discussion concludes about the ability of this method to detect the crop rows in agronomic images. Finally we consider the ability of this spatial-only approach to classify weeds from crop.

Bossu, Jérémie; Gée, Christelle; Truchetet, Frédéric

2007-10-01

318

Viability of water weeds and microalga in pulp and paper mill wastewater.  

PubMed

Water weeds Azolla pinnata and Lemna minor and the chlorophycean alga Scendesmus bijugatus were grown in a paper mill wastewater. The objective of the study was to assess the viability of these species upon exposure to such effluents and to assess their potential in the improvement of effluent quality. The wastewater was analysed before and after the treatment with these species. The growth of the alga and the hydrophytes was also measured. The algal assay revealed that the clear effluent will promote algal growth on addition of fertilizer while water weeds did not require fertilizer input. Both the algae and macrophytes could reduce the BOD and COD of the effluent. PMID:12395506

Joseph, V; Anto, S; Joseph, A

2001-01-01

319

What's in a Name? Can Mullein Weed Beat TB Where Modern Drugs Are Failing?  

PubMed Central

Common mullein weed (Verbascum thapsus) has a large number of synonyms and old local “nick names” which connect the plant with mycobacteria. A strong history of medicinal use has been uncovered for the treatment of tuberculosis, tubercular skin disease, leprosy, and mycobacterial disease in animals. Here, we examine problems encountered in treating such diseases today, the historical and scientific links between mullein and pathogenic bacteria, and the possibility that this common weed could harbour the answer to beating one of the world's biggest infectious killers.

McCarthy, Eibhlin; O'Mahony, Jim M.

2011-01-01

320

Critical period of weed control in winter canola (Brassica napus L.) in a semi-arid region.  

PubMed

In order to determine the critical period of weed control in winter canola (Brassica napus L. cv. Okapi) an experiment was carried out at research field of Tarbiat Modarres University, Tehran, Iran on 2004-2005 growing season. Fourteen experimental treatments which divided into two sets were arranged in Randomized complete blocks design with four replications. In the first set, the crop was kept weed-free from emergence time to two-leaf stage (V2), four-leaf stage (V4), six-leaf stage (V6), eight-leaf stage (V8), early flowering (IF), 50% of silique set (50% SS) and final harvest (H). In the second set, weeds where permitted to grow with the crop until above mentioned stages. In this study critical period of weed control was determined according to evaluate seed bank emerged weed biomass effect on canola grain yield loss using Gompertz and logistic equations. Result showed a critical time of weed control about 25 days after emergence (between four to six-leaf stages) with 5% accepted yield loss. Therefore, weed control in this time could provide the best result and avoid yield loss and damage to agroecosystem. PMID:18819576

Aghaalikhani, M; Yaghoobi, S R

2008-03-01

321

Executive Office for Weed and Seed. Site Accreditation. Participant's Guide, Session 2.  

National Technical Information Service (NTIS)

This guide provides material for the presentation of a two-day course on law-enforcement in the Weed and Seed environment. The training has been designed for law-enforcement officers, community members, business people and other members of you community w...

2001-01-01

322

National Process Evaluation of Operation Weed and Seed. Research in Brief.  

National Technical Information Service (NTIS)

The U.S. Department of Justice launched Operation Weed and Seed in 1991 to demonstrate that a large array of resources can be mobilized in a comprehensive, coordinated effort to control crime and drugs and to improve the quality of life in targeted high-c...

J. A. Roehl R. Huitt M. A. Wycoff A. Pate D. Rebovich K. Coyle

1996-01-01

323

Analysis of importations for biological control of insect pests and weeds in New Zealand  

Microsoft Academic Search

Importations of biological control agents for insect pests and weeds in New Zealand are summarized and factors contributing to the relative success of the programmes are examined. The establishment rate of 30.9% is similar to that achieved worldwide, but is significantly lower than the rate achieved in the island habitat of Hawaii. The pioneering role of New Zealand in biological

P. J. Cameron; R. L. Hill; J. Bain; W. P. Thomas

1993-01-01

324

Evolutionary Agroecology: the potential for cooperative, high density, weed-suppressing cereals  

PubMed Central

Evolutionary theory can be applied to improve agricultural yields and/or sustainability, an approach we call Evolutionary Agroecology. The basic idea is that plant breeding is unlikely to improve attributes already favored by millions of years of natural selection, whereas there may be unutilized potential in selecting for attributes that increase total crop yield but reduce plants’ individual fitness. In other words, plant breeding should be based on group selection. We explore this approach in relation to crop-weed competition, and argue that it should be possible to develop high density cereals that can utilize their initial size advantage over weeds to suppress them much better than under current practices, thus reducing or eliminating the need for chemical or mechanical weed control. We emphasize the role of density in applying group selection to crops: it is competition among individuals that generates the ‘Tragedy of the Commons’, providing opportunities to improve plant production by selecting for attributes that natural selection would not favor. When there is competition for light, natural selection of individuals favors a defensive strategy of ‘shade avoidance’, but a collective, offensive ‘shading’ strategy could increase weed suppression and yield in the high density, high uniformity cropping systems we envision.

Weiner, Jacob; Andersen, Sven B; Wille, Wibke K-M; Griepentrog, Hans W; Olsen, Jannie M

2010-01-01

325

Selection of the most efficient wavelength bands for discriminating weeds from crop  

Microsoft Academic Search

The aim of this study was to select the best combination of filters for detecting various weed species located within carrot rows. In-field images were taken under artificial lighting with a multispectral device consisting of a black and white camera coupled with a rotating wheel holding 22 interference filters in the VIS-NIR domain. Measurements were performed over a period of

A. Piron; V. Leemans; O. Kleynen; F. Lebeau; M.-F. Destain

2008-01-01

326

Field and laboratory evaluations of bioassays for nitrogen and phosphorus with algae and aquatic weeds  

Microsoft Academic Search

ABSTBACIY The rate of absorption of ammonia in the dark and the amount of orthophosphate extracted by boiling water can be used to follow changes in the nutritional status of nitrogen and phosphorus in algae and aquatic weeds with relation to changes in supply of these elements. Measurements of alkaline phosphatase activity carried out in phosphorus- free media can also

GEORGE P. FITZGERALD

1969-01-01

327

CLONING AND EXPRESSION OF KRP GENES FROM ADVENTITIOUS BUDS OF THE PERENNIAL WEED LEAFY SPURGE.  

Technology Transfer Automated Retrieval System (TEKTRAN)

We are interested in studying bud dormancy in the perennial weed leafy spurge. Adventitious buds of leafy spurge are capable of exhibiting all three types of dormancy (para-dormancy or apical dominance, endo-dormancy or innate dormancy, and eco-dormancy). Dormancy is defined as the temporary cessa...

328

How do floating aquatic weeds affect wetland conservation and development? How can these effects be minimised?  

Microsoft Academic Search

The most important floating aquatic weeds (FAWs) are Eichhornia crassipes, Salvinia molesta and Pistia stratiotes. E. crassipes and P. stratiotes reproduce sexually. All three species reproduce asexually. E. crassipes and S. molesta have particularly high growth rates. All can form dense mats and growth rates are increased by high nutrient levels and temperatures. Spread between continents and watersheds is largely

G. W. Howard; K. L. S. Harley

1997-01-01

329

Impact and legacy of R. Charudattan in biological control of weeds  

Technology Transfer Automated Retrieval System (TEKTRAN)

Raghavan “Charu” Charudattan is highly regarded internationally as a scientist, professor, mentor, and friend. Charu has authored four books, more than 100 refereed manuscripts, 24 book chapters, and hundreds of other publications. He holds 11 patents in the area of biological control of weeds and s...

330

EFFECT OF CELERIAC-LEEK INTERCROPPING ON WEEDS, INSECTS AND PLANT GROWTH  

Microsoft Academic Search

Intercropping of field vegetables favours utilization of water, nutrients, cropping area and productivity of cultivated plants. At the same time it can reduce occurrence of weeds, deseares and insects (Baumann et al. 2000, Lamberts 1980, Wiech 1993). These advantegous effects are attributed partially to allelopathic interaction between cultivated plants and other organism living in the field (Oleszek et al. 2001).

331

Potential Use of Abrasive Air-Propelled Agricultural Residues for Weed Control  

Technology Transfer Automated Retrieval System (TEKTRAN)

A new postemergence weed control tactic is proposed for organic production systems that results in plant abrasion and death upon assault from abrasive grits propelled by compressed air. Grit derived from granulated walnut shells was delivered by a sand blaster at 517 kPa at distances of 30 to 60 cm ...

332

USE OF A NATIVE INSECT AS A BIOLOGICAL CONTROL FOR AN INTRODUCED WEED  

Microsoft Academic Search

We have evaluated the potential of a North American aquatic weevil, Euhr- ychiopsis leconrei, to serve as an agent of biological control for an exotic weed, Eurasian watermilfoil (Myriophyllum spicatum), which is currently found throughout much of the United States and in some southern provinces of Canada. We have found this weevil on M. spicatum in lakes where populations of

SALLIE P. SHELDON; ROBERT P. CREED

333

Effect of weed management on quality of Roundup Ready Flex cotton  

Technology Transfer Automated Retrieval System (TEKTRAN)

Roundup Ready Flex cotton will be commercially available to growers in 2006. Alabama growers need information about this new technology under their growing conditions and weeds. Field trials were conducted at the Prattville Experiment Field, Prattville, AL and the Field Crops Unit, Shorter, AL in 20...

334

A peptide from insects protects transgenic tobacco from a parasitic weed  

Microsoft Academic Search

Parasitic plants present some of the most intractable weed problems for agriculture in much of the world. Species of root parasites such as Orobanche can cause enormous yield losses, yet few control measures are effective and affordable. An ideal solution to this problem is the development of parasite-resistant crops, but this goal has been elusive for most susceptible crops. Here

Noureddine Hamamouch; James H. Westwood; Idit Banner; Carole L. Cramer; Shimon Gepstein; Radi Aly

2005-01-01

335

Germination dimorphism and developmental flexibility in the ruderal weed Heterotheca grandiflora  

Microsoft Academic Search

Heterotheca grandiflora Nutt. (Asteraceae, tribe Astereae) is one of the few native Californian plant species increasing its range as a weed. The production of dimorphic seed, together with flexible development in either the annual or biennial habit, may contribute to its range expansion. Well dispersed disc achenes germinate rapidly to high percentages while poorly dispersed ray achenes show considerable dormancy,

Stephan D. Flint; Ivan G. Palmblad

1978-01-01

336

Effect of mulch on soil temperature, moisture, weed infestation and yield of groundnut in northern Vietnam  

Microsoft Academic Search

Groundnut (Arachis hypogaea L.) is one of the chief foreign exchange earning crops for Vietnam. However, owing to lack of appropriate management practices, the production and the area under cultivation of groundnut have remained low. Mulches increase the soil temperature, retard the loss of soil moisture, and check the weed growth, which are the key factors contributing to the production

A. Ramakrishna; Hoang Minh Tam; Suhas P. Wani; Tranh Dinh Long

2006-01-01

337

Testing the Weed Invasion Susecptibility Prediction Model for Leafy Spurge using Hyperspectral Remote Sensing  

Technology Transfer Automated Retrieval System (TEKTRAN)

Leafy spurge (Euphorbia esula L.) is a noxious invasive weed that infests over 1.2 million hectares of land in North America. One of the fundamental needs in leafy spurge management is cost-effective, large-scale, and long-term documentation and monitoring of plant populations. Leafy spurge is a g...

338

Review of approaches to evaluate the effectiveness of weed biological control agents  

Microsoft Academic Search

We review key issues, available approaches and analyses to encourage and assist practitioners to develop sound plans to evaluate the effectiveness of weed biological control agents at various phases throughout a program. Assessing the effectiveness of prospective agents before release assists the selection process, while post-release evaluation aims to determine the extent that agents are alleviating the ecological, social and

L. Morin; A. M. Reid; N. M. Sims-Chilton; Y. M. Buckley; K. Dhileepan; G. T. Hastwell; T. L. Nordblom; S. Raghu

2009-01-01

339

Biological control of weeds in crops: a coordinated European research programme (COST816)  

Microsoft Academic Search

For dominant weed species that are difficult to control by traditional means, the development of new, selective, control methods that can be implemented in integrated pest management (IPM) is essential. Here, biological control can be the appropriate means of control due to its high degree of selectivity and environmental safety (direct control value). The biocontrol strategy is based on a

H. MULLER-SCHARER; P. C. SCHEEPENS

1997-01-01

340

Winter Cover Crops and Vinegar for Early-Season Weed Control in Sustainable Cotton.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Weeds in cotton may be suppressed by winter cover crops and the use of organic herbicides such as vinegar. Black oat (Avena strigosa), and hairy vetch (Vicia villosa), winter cover crops were planted in a sustainable production field in the Lower Rio Grande Valley of Texas and were tilled prior to ...

341

Open-field Tests in Host-specificity Determination of Insects for Biological Control of Weeds  

Microsoft Academic Search

Open-field tests may be used for the host-specificity determination of insects used in the biological control of weeds. Such tests allow insects to exercise free choice of plants without constraints associated with the use of cages. Therefore, this testing method can generate host data on candidate biocontrol agents under more natural conditions than those obtained via cage tests. The literature

STEPHEN L. CLEMENT; MASSIMO CRISTOFARO

1995-01-01

342

Yielding ability and weed suppression of potato and wheat under organic nitrogen management  

Microsoft Academic Search

Keywords: chickweed, early growth, leaf area expansion, light interception, light use efficiency, manure, mineralisation, modelling, organic farming, organic matter, soil nitrogen content , Solanum tuberosum L., specific leaf area , Stellaria media (L.) Vill. , Triticum aestivum L, weed suppression .Understanding how to obtain good yields and farm profits in arable organic farming systems is useful for conventional and integrated

Delden van A

2001-01-01

343

Effects of organic farming on weed flora composition in a long term perspective  

Microsoft Academic Search

In 1987, the Ekhaga Experimental Farm in Sweden was established on a site that previously had been subjected to conventional farming, and has been managed since then as an organic farm. To study the effects of organic farming on weed population development and crop yields, two different crop rotations were designed, one adapted for animals (six fields) and one without

Anneli Lundkvist; Lennart Salomonsson; Lennart Karlsson; Ann-Marie Dock Gustavsson

2008-01-01

344

Weed Control in Peanut Grown in a High-Residue Conservation-Tillage System  

Technology Transfer Automated Retrieval System (TEKTRAN)

Information is needed on the role of cover crops as a weed control alternative due to the increase in adoption of conservation-tillage in peanut production. Field experiments were conducted from fall 1994 through fall 1997 in Alabama to evaluate three winter cereal cover crops in a high-residue con...

345

THE INVASIVE WEED TROPICAL SPIDERWORT INCREASES GROWTH UNDER ELEVATED ATMOSPHERIC CO2  

Technology Transfer Automated Retrieval System (TEKTRAN)

Invasive plants are considered to be a major threat to the earth’s biodiversity and cost U.S. agricultural and forest producers billions of dollars each year from decreased productivity and increased weed control costs. While considerable effort is being spent studying exotic plant pests, little co...

346

Relative importance of vertebrates and invertebrates in epigeaic weed seed predation in organic cereal fields  

Microsoft Academic Search

Exclosure trials were conducted in four organic cereal fields in The Netherlands in 1999 and 2000 to determine the relative importance of vertebrates and invertebrates in weed seed predation. The trials showed that seed predation by vertebrates was rather consistent and predictable, occurring on all fields and both years, being low early in the season, increasing towards mid-June and decreasing

P. R. Westerman; A. Hofman; L. E. M. Vet; W. Van der Werf

2003-01-01

347

EFFECTS OF INTERCROPPING AND FERTILIZATION ON WEED ABUNDANCE, DIVERSITY AND RESISTANCE TO INVASION  

Microsoft Academic Search

This paper aims to evaluate the effects of the cover crop type (Vicia villosa monoculture vs. V. villosa and Hodeum vulgare polyculture) and the type of fertilization (organic vs. chemical) on the structure of the weed community (biomass, number of species, diversity and evenness) and its invasibility through the experimental introduction of Brassica sp. seeds as a target invader species.

M. A. Altieri

348

Phytosociological and conservational study of the arable weed communities in western Hungary  

Microsoft Academic Search

The present study surveyed the weed vegetation on extensively managed arable fields and unsprayed field edges in western Hungary, based on 1698 phytosociological relevés collected between 1995 and 2005. The separation of the 15 vegetation units was conducted with the traditional comparative tabular method, and the diagnostic species were determined with statistical fidelity measures. The numerical analyses show that the

Gyula Pinke; Robert Pál

2008-01-01

349

Strigolactones: Chemical Signals for Fungal Symbionts and Parasitic Weeds in Plant Roots  

PubMed Central

• Aims Arbuscular mycorrhizae are formed between >80 % of land plants and arbuscular mycorrhizal (AM) fungi. This Botanical Briefing highlights the chemical identification of strigolactones as a host-recognition signal for AM fungi, and their role in the establishment of arbuscular mycorrhizae as well as in the seed germination of parasitic weeds. • Scope Hyphal branching has long been described as the first morphological event in host recognition by AM fungi during the pre-infection stages. Host roots release signalling molecules called ‘branching factors’ that induce extensive hyphal branching in AM fungi. Strigolactones exuded from host roots have recently been identified as an inducer of hyphal branching in AM fungi. Strigolactones are a group of sesquiterpenes, previously isolated as seed germination stimulants for the parasitic weeds Striga and Orobanche. Parasitic weeds might find their potential hosts by detecting strigolactones, which are released from plant roots upon phosphate deficiency in communication with AM fungi. In addition to acting as a signalling molecule, strigolactones might stimulate the production of fungal symbiotic signals called ‘Myc factors’ in AM fungi. • Conclusions Isolation and identification of plant symbiotic signals open up new ways for studying the molecular basis of plant–AM-fungus interactions. This discovery provides a clear answer to a long-standing question in parasitic plant biology: what is the natural role for germination stimulants? It could also provide a new strategy for the management and control of beneficial fungal symbionts and of devastating parasitic weeds in agriculture and natural ecosystems.

AKIYAMA, KOHKI; HAYASHI, HIDEO

2006-01-01

350

Evaluation of hyperspectral reflectance data for discriminating among six aquatic weeds  

Technology Transfer Automated Retrieval System (TEKTRAN)

In situ hyperspectral reflectance data were studied at 50 wavebands (10 nm bandwidth) over the 400 to 900 nm spectral range to determine their potential for discriminating among six aquatic weed species: curly-leaf pondweed (Potamogeton crispus L.), hydrilla [Hydrilla verticillata (L. F.) Royle], Eu...

351

Dry bean (Phaseolus vulgaris L.) yield components: Weed control and soil moisture interactions  

Technology Transfer Automated Retrieval System (TEKTRAN)

Dry bean (Phaseolus vulgaris L.) is an alternative cropping option for the Southern Plains region with increasing production and market potential. Producers report that weed competition is the most detrimental factor influencing bean yields and therefore profitability. In addition, depending on th...

352

Weed Control and Cotton Response to Combinations of Glyphosate and Trifloxysulfuron 1  

Microsoft Academic Search

Greenhouse and field studies were conducted to evaluate potential interactions between glyphosate and trifloxysulfuron on barnyardgrass, browntop millet, hemp sesbania, seedling john- songrass, pitted morningglory, prickly sida, sicklepod, and velvetleaf control as well as cotton injury and yield. In the greenhouse, glyphosate at 840 g ae\\/ha controlled all weed species 62 to 99%, which was better than trifloxysulfuron at 2.5

CLIFFORD H. KOGER; ANDREW J. PRICE; KRISHNA N. REDDY

2005-01-01

353

Mustard (Sinapis alba) Seed Meal Suppresses Weeds in Container Grown Ornamentals  

Technology Transfer Automated Retrieval System (TEKTRAN)

Mustard seed meal is a byproduct of mustard (Sinapis alba L.) grown and oil production. Developing new uses for mustard seed meal could increase the profitability of growing mustard. Seed meal of mustard, var. ‘IdaGold’ was applied to the soil surface to evaluate its effect on several common weeds...

354

The Springfield Weed and Seed Initiative: A Process Description and Evaluation.  

ERIC Educational Resources Information Center

|A process description and preliminary evaluation are provided for the Weed and Seed initiative in Springfield (Illinois). This initiative involved local, state, and federal resources in projects that included (1) facility improvement, (2) drug prevention, (3) youth education and child care, (4) jobs and vocational training, (5) resident…

Hanna, Donald G.

355

Weed suppression potential of 'Rondo' and other indica rice germplasm lines  

Technology Transfer Automated Retrieval System (TEKTRAN)

A high-yielding indica rice, 'Rondo' (4484-1693; PI 657830) which carries resistances to major rice diseases, was previously developed. We evaluated the weed suppression potential of Rondo, a sister line (4484-1665), and other indica lines against barnyardgrass in field plots in Stuttgart, AR, using...

356

Mass-production of the arundo wasp and other insects for biological weed control  

Technology Transfer Automated Retrieval System (TEKTRAN)

Mass-rearing is underutilized in biological weed control, despite the wealth of biological information available for insects that have been released and the utility of inoculative releases using large numbers of insects to maximize establishment. Mass-rearing is particularly uncommon for biological...

357

Wood chip mulch thickness effects on soil water, soil temperature, weed growth, and landscape plant growth  

Technology Transfer Automated Retrieval System (TEKTRAN)

Wood chip mulches are used in landscapes to reduce soil water evaporation and competition from weeds. A study was conducted over a three-year period to determine soil water content at various depths under four wood chip mulch treatments and to evaluate the effects of wood chip thickness on growth of...

358

Method for Screening Bacteria and Application Thereof for Field Control of the Weed Downy Brome.  

National Technical Information Service (NTIS)

A method for screening bacteria to select strains which inhibit the weed downy brome in small grain crops under field conditions and method for field application of the bacteria to inhibit downy brome in small grain crops in a commercial setting are descr...

L. F. Elliott A. C. Kennedy

1988-01-01

359

Comparative study on chemical pretreatment methods for improving enzymatic digestibility of crofton weed stem.  

PubMed

In order to utilize and control the invasive weed, crofton weed (Eupatorium adenophorum Spreng), a potential pathway was proposed by using it as a feedstock for production of fermentable sugars. Three chemical pretreatment methods were used for improving enzymatic saccharification of the weed stem. Mild H2SO4 pretreatment could obtain a relatively high yield of sugars in the pretreatment (32.89%, based on initial holocellulose), however, it led to only a slight enhancement of enzymatic digestibility. NaOH pretreatment could obtain a higher enzymatic conversion ratio of cellulose compared with H2SO4 pretreatment. Peracetic acid (PAA) pretreatment seemed to be the most effective for improving enzymatic saccharification of the weed stem in the three chemical pretreatment methods under the same conditions. The conversion ratio of cellulose in the sample pretreated by PAA under the "optimal" condition was increased to 50% by cellulase loading of 80 FPU/g cellulose for 72 h incubation. A number of empirical quadratic models were successfully developed according to the experimental data to predict the yield of sugar and degree of delignification. PMID:17709243

Zhao, Xuebing; Zhang, Lihua; Liu, Dehua

2007-08-20

360

Winter Cover Crops and Vinegar for Early-Season Weed Control in Sustainable Cotton  

Microsoft Academic Search

Weeds may be suppressed by winter cover crops and the use of organic herbicides such as vinegar. Black oat (Avena strigosa) and hairy vetch (Vicia villosa) winter cover crops were planted for 2 years as part of a sustainable production system for cotton in the Lower Rio Grande Valley of Texas, and were till-killed each spring prior to cotton planting.

P. J. Moran; S. M. Greenberg

2008-01-01

361

(Keywords: agricultural pests, aquatic weeds, biodiversity, biological control, endangered species, Gastropoda, Mollusca, schistosomiasis)  

Microsoft Academic Search

The use of snails as biocontrol agents against other snails and against aquatic weeds is reviewed, evaluating their success and their impacts on non-target organisms. The predatory snail Euglandina rosea (and other species), although widely used against Achatina fulica (the giant African land snail) on Pacific and Indian Ocean islands, has not been shown to control A. fulica but has

ROBERT H. COWIE

362

Seed treatment technology: An attractive delivery system for controlling root parasitic weed Striga with mycoherbicide  

Microsoft Academic Search

Coating sorghum seeds with Fusarium oxysporum (Foxy 2) for control of the root parasitic weed Striga, appears to be an attractive option for minimizing the inoculum amount, establishing the biocontrol agent in the potential infection zone of the host plants, and offering a simple, easy and economical delivery system. Our investigations resulted in the selection of appropriate seed coating materials

Abuelgasim Elzein; Juergen Kroschel; Vibeke Leth

2006-01-01

363

Title: Evaluation and Utilization of Allelopathic Festuca rubra Turfgrass Cultivars for Alternative Weed Management Strategies  

Microsoft Academic Search

Recent experiments in Ithaca and Riverhead NY have shown that fine fescue cultivars Intrigue, Reliant and Oxford were most suppressive in field and laboratory settings due to their allelopathic activity and their ability to establish readily in a field setting. The cultivars Treasure and Boreal were least weed suppressive in both sites in 2 years of replicated trials. Mode of

Leslie A. Weston; Cecile Bertin; Andrew F. Senesac; Frank Rossi; Peder Weibull

364

Effects of Brassicaceae seed meal-amended soil on germination and growth of weed seeds  

Technology Transfer Automated Retrieval System (TEKTRAN)

The need for sustainable agricultural production systems has generated demand for effective non-synthetic alternative weed control strategies. For some vegetable crops there are few herbicide options available, and there is little prospect of new herbicides being registered for vegetable crops. Br...

365

USING QUICKBIRD SATELLITE IMAGERY TO DISTINGUISH TWO NOXIOUS WEEDS IN SOUTHERN TEXAS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Giant reed (Arundo donax L.) and spiny aster [Leucosyris spinosus (Beaty.) Greene] are noxious weeds that invade riparian and rangeland areas. QuickBird high resolution (2.8 m) satellite imagery was evaluated for distinguishing spiny aster and giant reed infestations in southern Texas. Unsupervis...

366

Automatic Weed Control System For Transplanted Processing Tomatoes Using X-ray Stem Sensing  

Technology Transfer Automated Retrieval System (TEKTRAN)

A stem detection system was developed for automatic weed control in transplanted tomato fields. A portable x-ray source projected an x-ray beam perpendicular to the crop row and parallel to the soil surface. The plant’s main stem absorbs x-ray energy, decreasing the detected signal and allowing ste...

367

MSMA ANTAGONIZES GLYPHOSATE AND GLUFOSINATE EFFICACY ON BROADLEAF AND GRASS WEEDS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Field and greenhouse studies were conducted to investigate the compatibility of MSMA in a tank mixture with glyphosate or glufosinate for broadleaf and grass weed control. Glyphosate, glufosinate, and MSMA were evaluated at 0.5x, 1x, and 2x rates, with 1x rates of 0.84 kg ae/ha, 0.5 kg ai/ha, and 2...

368

(Eds) Proceedings of the XII International Symposium on Biological Control of Weeds  

Technology Transfer Automated Retrieval System (TEKTRAN)

This Proceeding book presents the different topics discussed during the 20th Symposium on Biological Control of Weeds in la Grande Motte, France. Topics were: 1)The economic impact; 2)Regulations and feasibility in Europe; 3)The role of modelling in population dynamics; 4)The evolutionary biology; 5...

369

An easy and rapid method using microscopy to determine herbicide effects in Poaceae weed species  

Microsoft Academic Search

A new, easy, rapid and relatively inexpensive method using microscopy has been developed for the detection of herbicide effects in leaves of grass weed species displaying no visual signs of damage. The method has potential to be used as a tool to indicate future death of grass species due to herbicide exposure by observing phytochemical effects, i.e. early-warning effects. In

Maibritt Hjorth; Laurence Mondolot; Bruno Buatois; Claude Andary; Sylvie Rapior; Per Kudsk; Solvejg K Mathiassen; Helle W Ravn

2006-01-01

370

IRRIGATION AND FERTILIZER PLACEMENT EFFECTS PLANT AND WEED GROWTH IN CONTAINER TREE PRODUCTION  

Technology Transfer Automated Retrieval System (TEKTRAN)

The objective of this research was to determine the effect of fertilizer placement and irrigation method on plant and weed growth in production of Quercus shumardii. On 24 April 2003, three gallon (11.4-L) liners were potted into 13.2 gallon (50-L) containers using a standard nursery mix. Treatment ...

371

Corn Gluten Meal as an Alternative Weed Control Option for Spring-Transplanted Onions  

Microsoft Academic Search

Successful screening of suitable onion (Allium cepa L.) varieties, viable production areas, and potential marketing options suggest that onions are a potential alternative crop for Oklahoma and northeast Texas. Unfortunately, onion's slow growth rate, short height, non-branching plant structure, low leaf area, and shallow root system can result in a total loss of marketable yields as a result of weed

Charles L. Webber III; James W. Shrefler; Merritt J. Taylor

2008-01-01

372

Target detection as a tool of selective spray application on trees and weeds in orchards  

NASA Astrophysics Data System (ADS)

A spectral detection system discriminating the targets for the non target area was tested during spray applications in apple and pear orchards. The objective of the test was to evaluate the accuracy of the system working at different application parameters and to estimate the rate of possible spray savings obtained during applications on the trees of different size and weeds of different density. The system consisted of the spray units equipped with optic sensor and a control unit which could operate up to 16 spray units. Each spray unit had an optic detector and two light sources emitting two beams of light at the wavelengths 670 and 750. The ratio between emitted and reflected light for each wavelength was the basis for discriminating between the presence or the absence of chlorophyll. The information was processed and used to control the electric solenoid valves opening or shutting off the nozzles. The target detection system worked technically properly. It enabled the selective spray application with spray savings adequate to the tree row profile. In intensive apple and pear orchards 16-25 percent reduction of spray volume was obtained. For herbicide applications the detection system discriminated weeds for the bare ground. Both sensitivity of the sensors and weed density had a significant influence on the spray savings. At medium sensitivity, a considerable spray saving amounting 23 percent was obtained only on the plots with very low weed coverage.

Doruchowski, Grzegorz; Jaeken, Peter; Holownicki, Ryszard

1999-01-01

373

QUALITY OF HARVESTED SEED ASSOCIATED WITH SOYBEAN CULTIVARS AND HERBICIDES UNDER WEED-FREE CONDITIONS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Different herbicides were applied to soybean plants in field plots planted to different soybean cultivars located at four locations in Illinois between 1997 and 2000. Treatments varied from hand weeded to preemergence herbicides to postemergence herbicides. Soybean seeds were harvested and evaluat...

374

Simulating crop–parasitic weed interactions using APSIM: Model evaluation and application  

Microsoft Academic Search

The parasitic weed Orobanche crenata inflicts major damage on faba bean, lentil, pea and other crops in Mediterranean environments. The development of methods to control O. crenata is to a large extent hampered by the complexity of host–parasite systems. Using a model of host–parasite interactions can help to explain and understand this intricacy. This paper reports on the evaluation and

J. H. Grenz; A. M. Manschadi; P. deVoil; H. Meinke; J. Sauerborn

2006-01-01

375

Responses of a Widespread Weed and an Endangered Congeneric Plant to Potassium  

Microsoft Academic Search

Acid rain is leading to soil potassium (K) loss. A hydroponic experiment was conducted to determine the growth and physiological and stoichiometrical traits of Mosla hangchowensis (an endangered plant) and M. scabra (a weed) in response to three K concentrations. For M. hangchowensis, compared with standard Knop's solution (K3), low K (K0) induced reductions in net photosynthetic rate, soluble protein

Jie Chang; Meng Wang; Zhen Liu; Ying Ge

2010-01-01

376

Epiphytic survival of Pseudomonas viridiflava on tomato and selected weed species  

Microsoft Academic Search

A rifampicin-nalidixic acid mutant of Pseudomonas viridiflava (PV) was studied in the field and greenhouse with respect to its epiphytic survival on the roots and foliage of a susceptible (FM 6203) and resistant (Ontario 7710) tomato cultivar and 16 weed species. In the field, populations varied between years, which was attributed to differences in environmental conditions. Hot, dry conditions caused

R. L. R. Mariano; S. M. McCarter

1993-01-01

377

Hypermedia in the Plant Sciences: The Weed Key and Identification System/Videodisc.  

ERIC Educational Resources Information Center

In cooperation with a university educational technology unit, an agronomy professor used hypercard and videodisk technology to develop a computer program for identification of 181 weed species based on user-selected characteristics. This solution was found during a search for a way to organize course content in a concise, manageable system. (MSE)

Ragan, Lawrence C.

1991-01-01

378

Effect of Row Spacing and Sorgaab on Sunflower and its Weeds  

Microsoft Academic Search

A field study was conducted to evaluate the effect of row spacing and Sorgaab (water extract of sorghum) on two kharif weeds, growth and yield of sunflower during 1999. The results revealed that combination of row spacing and Sorgaab at 20 DAS increased yield by 25% while dry weight plant-1, number of achenes head-1 and 1000-achene weight was maximum at

RAB NAWAZ; RIAZ AHMAD; Z. A. CHEEMA; TARIQ MEHMOOD

379

Synergistic interactions between an exotic honeybee and an exotic weed: pollination of Lantana camara in Australia  

Microsoft Academic Search

Summary Lantana camara, a woody shrub originating in south and central America, is among the most widespread and troublesome exotic weeds of the old-world tropics. It invades pasture, crops and native ecosystems, causing substantial economic losses and environmental degra- dation. In Australia alone, L. camara is currently estimated to cover c. 40 000 km 2 . In glasshouse studies we

DG OULSON

2004-01-01

380

Foraging behaviour of bee pollinators on the tropical weed Triumfetta semitriloba : departure rules from flower patches  

Microsoft Academic Search

Summary We studied the departure rules from flower patches used by bee pollinators of the tropical shrub weed Triumfetta semitriloba Jacq. (Tiliaceae). Flowering plants were distributed in well delimited clumps, in each of two pasture areas (A1 and A2) and one area of forest gap (A3), in Viçosa, southeastern Brazil. Five solitary bee species, Augochlorella michaelis, Augochloropsis cupreola, Pseudocentron paulistana,

R. G. Collevatti; L. A. O. Campos; J. H. Schoereder

1997-01-01

381

Population dynamics of weeds in no-tillage and conventional crop systems.  

PubMed

Population dynamics of weeds in successive maize and bean crops were evaluated in two soil management systems (conventional and no-tillage), for two maize applications (grain and silage), and in four consecutive growing seasons. Every year, conventional tillage consisted in plowing and harrowing before sowing. In no-tillage, chemical weed desiccation was made with the mixture glyphosate + 2.4-D. To control weeds, the mixture fluazifop-p-butil + fomesafen was applied on the bean crop in all the planting seasons, and the herbicides nicosulfuron + atrazine on maize after crop emergence (1998--1999, 1999--2000, 2001--2002) and atrazine + metolachlor before emergence (2000--2001). Purple nutsedge (Cyperus rotundus) was the most important species under conventional soil tillage; while in no-tillage the dicotyledonous weed species (Amaranthus deflexus, Bidens pilosa, Euphorbia heterophylla, Galinsoga parviflora Ipomoea grandifolia) were the most relevant. Regardless of the maize use, the C. rotundus population and tuber bank, with prevailingly dormant tubers, was considerably reduced in no-tillage compared with the conventional system. PMID:15656169

Machado, Aroldo Ferreira Lopes; Jakelaitis, Adriano; Ferreira, Lino Roberto; Agnes, Ernani Luiz; Santos, Leonardo David Tuffi

2005-01-01

382

PINEBARK MINI-NUGGETS PROVIDE EFFECTIVE WEED CONTROL IN NURSERY CROPS GROWN IN LARGE CONTAINERS  

Technology Transfer Automated Retrieval System (TEKTRAN)

The objective of this study was to evaluate fresh pine bark mini nuggets as a long term weed control in large container nursery crops. Crapemyrtle (Lagerstroemia x ‘Acoma’) were transplanted from trade gallon containers into 7 gallon containers September 27, 2004 and treated on October 8, 2004. All ...

383

USE OF PLASTIC FILMS FOR WEED CONTROL DURING FIELD ESTABLISHMENT OF MICROPROPAGATED HARDWOODS  

Microsoft Academic Search

This study compares the use of plastic films to conventional methods for establishing hardwoods on a recently cultivated old field site using 1-year-old micropropagated plantlets of white ash (Fraxinus americam L.) and silver maple (Acer saccharinurn L.). After one growing season in the field, height of plantlets with all weed control treatments exceeded the height of the plantlets in the

J. W. Van Sambeek; John E. Reecez; Carl A. Huetternanz

384

USE OF PLASTIC FILMS FOR WEED CONTROL DURING F_LD ESTABLISHMENT OF MICROPROPAGATED HARDWOODS  

Microsoft Academic Search

This study compares the use of plastic films to conventional methods for establishing hardwoods on a recently cultivated old field site using 1-year-old micropropagated plantlets of white ash (Fraxinus americana L.) and silver maple (Acer saccharinum L.). After one growing season in the field, height of plantlets with all weed control treatments exceeded the height of the planters in the

J. W. Van Sambeek; John E. Preece; Carl A. Huetteman; Paul L. Roth

385

Weed control during establishment of napiergrass (Pennisetum purpureum Schum.) in Georgia.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Napiergrass is being considered for a possible feedstock for cellulosic ethanol production. Weed control during crop establishment has not been previously studied. Field studies were conducted at the UGA Research Station in Plains, GA and the Ft. Valley State University Research Farm. New field plan...

386

X-ray based stem detection in an automatic tomato weeding system  

Technology Transfer Automated Retrieval System (TEKTRAN)

A stem detection system was developed for automatic weed control in transplanted tomato fields. A portable x-ray source projected an x-ray beam perpendicular to the crop row and parallel to the soil surface. The plant’s main stem absorbs x-ray energy, decreasing the detected signal and allowing stem...

387

Herbicide-Resistance in Crops and Weeds: A Historical and Current Perspective  

Technology Transfer Automated Retrieval System (TEKTRAN)

Herbicides are the principal economic means of weed management on >90% of U.S. farmland. Herbicide-resistant crop cultivars have been used widely since 1995. Pest disciplines and other life sciences have various definitions of resistance that share commonalities. Development of herbicide resistant w...

388

REMOTE MAPPING OF TWO INVASIVE WEEDS IN THE RIO GRANDE SYSTEM OF TEXAS  

Technology Transfer Automated Retrieval System (TEKTRAN)

The Rio Grande is a major source of water for agricultural and municipal uses in Texas and northern Mexico. Water shortages in the Rio Grande have been significantly impacted by the invasion and spread of the invasive weed species giant reed (Arundo donax L.) and saltcedar (Tamarix chinensis Lour.)...

389

Potential of weed species applied to remediation of soils contaminated with heavy metals.  

PubMed

To screen out a series of ideal plants that can effectively remedy contaminated soils by heavy metals is the main groundwork of phytoremediation engineering and the first step of its commercial application on a large scale. In this study, accumulation and endurance of 45 weed species in 16 families from an agricultural site were in situ examined by using the pot-culture field experiment, and the remediation potential of some weed species with high accumulation of heavy metals was assayed. The results showed that Solanum nigrum and Conyza canadensis can not only accumulate high concentration of Cd, but also strongly endure to single Cd and Cd-Pb-Cu-Zn combined pollution. Thus 2 weed species can be regarded as good hyperaccumulators for the remediation of Cd-contaminated soils. Although there were high Cd-accumulation in Artemigia selengensis, Znula britannica and Cephalanoplos setosum, their biomass was adversely affected due to action of heavy metals in the soils. If the problem of low endurance to heavy metals can be solved by a reinforcer, 3 weed species can be perhaps applied commercially. PMID:15559831

Wei, Shu-He; Zhou, Qi-Xing; Wang, Xin; Cao, Wei; Ren, Li-Ping; Song, Yu-Fang

2004-01-01

390

Iowa Commercial Pesticide Applicator Manual, Category 1A: Agricultural Weed Control.  

ERIC Educational Resources Information Center

|This manual provides information needed to meet the standards for pesticide applicator certification. Weeds, their effects, and control in relation to crop production are presented. Pre- and post-emergence treatments are discussed for row crops such as corn and soybeans. Problems with herbicide application to grass pastures, small grains, and…

Jennings, Vivan M.; Ryan, Stephen O.

391

Weeding and Seeding: Programming for Alcohol Abuse Prevention and Wellness Enhancement in an Undergraduate Population  

ERIC Educational Resources Information Center

|College students who are no longer fully adolescent and not yet fully adult are frequently at risk for developing habits of excessive alcohol use, with consequent poor study habits and aberrant socialization patterns. "Weeding out" such trends is the work of prevention programs on campus. "Seeding" with other pro-social norms becomes the second…

Halligan, Fredrica R.; Pohl, Jonathan A.; Smith, M. Katrina

2006-01-01

392

Allelopathic effect of some essential oils and components on germination of weed species  

Microsoft Academic Search

In this study, allelopathic effects of some essential oil plants (Carum carvi L., Coriandrum sativum L., Foeniculum vulgare Mill., Lavandula stoechas L., Mentha spicata L.,Origanum onites L., Pimpinella anisum L., Rosmarinus officinalis L., Salvia officinalis L. and Thymbra spicata L.) were investigated against some common weed species (Alcea pallida Waldst. & Kit., Amaranthus retroflexus L., Centaurea salsotitialis L., Raphanus raphanistrum

Sebile Azirak; Sengul Karaman

2008-01-01

393

Allelopathic Potential of Various Plant Species on Downy Brome: Implications for Weed Control in Wheat Production  

Microsoft Academic Search

Allelopathy, the ability of plants to inhibit germination of other plants, is an untapped resource for weed control in crops that could revolutionize organic crop production. The main objective of the study was to evaluate allelopathic potential of various plant species on downy brome (Bromus tectorum L.), a major pest of wheat (Triticum aestivum L.). To screen for potential allelopathy,

Stephen Machado

394

Nematodes Parasitic on Sea Weeds of the Genera Ascophyllum and Fucus  

Microsoft Academic Search

In 1892 Barton described galls found on the sea weed Ascophyllum nodosum from the Isle of Cumbrae, west coast of Scotland, and from Stonehaven, east coast of Scotland. The affected areas on the thallus of the plant appeared as swellings covered with small rounded nodules, and were almost invariably confined to the parts of the thallus just above or below

John W. Coles

1958-01-01

395

Selection of test plant list for weed biological control with molecular and biochemical data  

Technology Transfer Automated Retrieval System (TEKTRAN)

The initial steps of weed biological control programs involve the determination of the host range of a prospective agent prior to consideration for release. Accurately predicting the host range of a potential agent is fundamental to this process. This may be conducted first in the country of origin ...

396

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

Microsoft Academic Search

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

Paul R. Schreiner; Kelly L. Ivors; John N. Pinkerton

2001-01-01

397

An Agricultural Mobile Robot with Vision-Based Perception for Mechanical Weed Control  

Microsoft Academic Search

This paper presents an autonomous agricultural mobile robot for mechanical weed control in outdoor environments. The robot employs two vision systems: one gray-level vision system that is able to recognize the row structure formed by the crops and to guide the robot along the rows and a second, color-based vision system that is able to identify a single crop among

Björn Åstrand; Albert-Jan Baerveldt

2002-01-01

398

Adsorption of Methylene Blue Dye on Pure and Carbonized Water Weeds  

Microsoft Academic Search

The influence of process variables in batch adsorption has been used to assess the removal of methylene blue dye from aqueous solution using pure and carbonized biomasses of water hyacinth and water spinach. Dried leaves of the water weeds were carbonized at temperature up to 750°C. The optimum removal of dye was achieved at pH 10, 30°C, and 55 min

Timi Tarawou; Michael Horsfall Jr

2007-01-01

399

Crop Species Diversity Affects Productivity and Weed Suppression in Perennial Polycultures under Two Management Strategies  

Microsoft Academic Search

Species diversity can increase natural grass- lands productivity but the effect of diversity in agricultural systems is not well understood. Our objective was to measure the effects of spe- cies composition, species richness, and har- vest management on crop and weed biomass in perennial herbaceous polycultures. In 2003, 49 combinations of seven species (legumes, C3 and C4 grasses) including all

Valentín D. Picasso; E. Charles Brummer; Matt Liebman; Philip M. Dixon; Brian J. Wilsey

2008-01-01

400

Status and natural enemies of the weed, Lantana camara in Micronesia  

Microsoft Academic Search

The neotropical weed Lantana camara was first introduced to Micronesia as an ornamental plant around the turn of the century. It quickly established and, within the space of few decades, became a problem on many of the islands there. The first attempts at biological control of lantana in this region started shortly after World War II and continued, largely on

G. R. W. Denton; R. Muniappan; M. Marutani

1991-01-01

401

Effects of segmenting, signalling, and weeding on learning from educational video  

Microsoft Academic Search

Informed by the cognitive theory of multimedia learning, this study examined the effects of three multimedia design principles on undergraduate students' learning outcomes and perceived learning difficulty in the context of learning entomology from an educational video. These principles included segmenting the video into smaller units, signalling to direct students' attention to relevant information, and weeding to remove any non-essential

Mohamed Ibrahim; Pavlo D. Antonenko; Carmen M. Greenwood; Denna Wheeler

2011-01-01

402

L-DONAX, a growth model of the invasive weed species, Arundo donax L  

Microsoft Academic Search

Arundo donax L. is a perennial reed and is an invasive weed of riparian systems in North America. A structural model (L-DONAX) of the species was constructed using L-system modelling in order to assist in understanding and demonstrating the complexities of the plant's development and structure. The model produces a realistic number of plant components from a single rhizome segment

David Thornby; David Spencer; Jim Hanan; Anna Sher

2007-01-01

403

COVER CROP MANAGEMENT AND WEED SUPPRESSION IN NO-TILLAGE SWEET CORN PRODUCTION  

Technology Transfer Automated Retrieval System (TEKTRAN)

Cover crops combined with conservation tillage practices can minimize chemical inputs and improve soil quality, soil water holding capacity, weed suppression and crop yields. No-tillage production of sweet corn (Zea mays var. rugosa L.) was studied for two years at the Beltsville Agricultural Resea...

404

USING HYPERSPECTRAL REMOTE SENSING TO MAP NOXOUS WEEDS IN RANGELANDS: LEAFY SPURGE IN NOTHEASTERN WYOMING  

Technology Transfer Automated Retrieval System (TEKTRAN)

Leafy spurge, Euphorbia esula L. is an adventive, perennial weed that infests approximately 1.2 million hectares of land in North America. One of the fundamental needs in leafy spurge management is cost-effective, large-scale, and long-term documentation and monitoring of plant populations. Leafy ...

405

GENETIC DIVERSITY IN POPULATIONS OF XANTHOMONAS CAMPESTRIS PV. CAMPESTRIS IN CRUCIFEROUS WEEDS IN CENTRAL COASTAL CALIFORNIA  

Technology Transfer Automated Retrieval System (TEKTRAN)

Xanthomonas campestris pv. campestris (Xcc) infects a large number of cruciferous plants, including weeds. California has one of the largest and most diverse populations of wild cruciferous plants in the world. Although considerable information is available on the genetic diversity of Xcc in commerc...

406

Discrimination of corn from monocotyledonous weeds with ultraviolet (UV) induced fluorescence.  

PubMed

In production agriculture, savings in herbicides can be achieved if weeds can be discriminated from crop, allowing the targeting of weed control to weed-infested areas only. Previous studies demonstrated the potential of ultraviolet (UV) induced fluorescence to discriminate corn from weeds and recently, robust models have been obtained for the discrimination between monocots (including corn) and dicots. Here, we developed a new approach to achieve robust discrimination of monocot weeds from corn. To this end, four corn hybrids (Elite 60T05, Monsanto DKC 26-78, Pioneer 39Y85 (RR), and Syngenta N2555 (Bt, LL)) and four monocot weeds (Digitaria ischaemum (Schreb.) I, Echinochloa crus-galli (L.) Beauv., Panicum capillare (L.), and Setaria glauca (L.) Beauv.) were grown either in a greenhouse or in a growth cabinet and UV (327 nm) induced fluorescence spectra (400 to 755 nm) were measured under controlled or uncontrolled ambient light intensity and temperature. This resulted in three contrasting data sets suitable for testing the robustness of discrimination models. In the blue-green region (400 to 550 nm), the shape of the spectra did not contain any useful information for discrimination. Therefore, the integral of the blue-green region (415 to 455 nm) was used as a normalizing factor for the red fluorescence intensity (670 to 755 nm). The shape of the normalized red fluorescence spectra did not contribute to the discrimination and in the end, only the integral of the normalized red fluorescence intensity was left as a single discriminant variable. Applying a threshold on this variable minimizing the classification error resulted in calibration errors ranging from 14.2% to 15.8%, but this threshold varied largely between data sets. Therefore, to achieve robustness, a model calibration scheme was developed based on the collection of a calibration data set from 75 corn plants. From this set, a new threshold can be estimated as the 85% quantile on the cumulative frequency curve of the integral of the normalized red fluorescence. With this approach the classification error was nearly constant (16.0% to 18.5%), thereby indicating the potential of UV-induced fluorescence to reliably discriminate corn from monocot weeds. PMID:21211148

Panneton, Bernard; Guillaume, Serge; Samson, Guy; Roger, Jean-Michel

2011-01-01

407

Effect of mungbean (Vigna radiate) living mulch on density and dry weight of weeds in corn (Zea mays) field.  

PubMed

Living mulch is a suitable solution for weeds ecological management and is considered as an effective method in decreasing of weeds density and dry weight. In order to evaluate of mungbean living mulch effect on density and dry weight of weeds in corn field, an experiment was conducted as a split plot based on randomized complete block design with four blocks in Research Field of Department of Agronomy, Karaj Branch, Islamic Azad University in 2010. Main plots were time of mungbean suppression with 2,4-D herbicide in four levels (4, 6, 8 and 10 leaves stages of corn) and control without weeding and sub plots were densities of mungbean in three levels (50%, 100% and 150% more than optimum density). Density and dry weight of the weeds were measured in all plots with a quadrate (60 x 100 cm) in 10 days after tasseling. Totally, 9 species of weeds were identified in the field, which included 4 broad leave species that were existed in all plots. The results showed that the best time for suppression of mungbean is the 8 leaves stage of corn, which decreased density and dry weight of weeds, 53% and 51% in comparison with control, respectively. Increase of density of mungbean from 50% into 150% more than optimum density, decrease the density and dry weight of weeds, 27.5% and 22%, respectively. It is concluded that the best time and density for suppression mungbean was 8 leaves stage of corn, and 150% more than optimum density, which decreased density and dry weight of the weeds 69% and 63.5% in comparison with control, respectively. PMID:22696966

Moghadam, M Bakhtiari; Vazan, S; Darvishi, B; Golzardi, F; Farahani, M Esfini

2011-01-01

408

Cover crop mulch and weed management influence arthropod communities in strip-tilled cabbage.  

PubMed

Cover crop mulch and weeds create habitat complexity in agricultural fields that may influence arthropods. Under strip-tillage systems, planting rows are tilled and preestablished cover crops can remain between rows. In field experiments conducted in Michigan in 2010 and 2011, a preestablished oat (Avena sativa L.) cover crop was allowed to grow between rows of strip-tilled cabbage and killed at 0, 9-14, or 21-27 d after transplanting (DAT). The effects of herbicide intensity and oat kill date on arthropods, weeds, and crop yield were examined. Two levels of herbicide intensity (low or high) were used to manipulate habitat vegetational complexity, with low weed management intensity resulting in more weeds, particularly in 2010. Oat kill date manipulated the amount of cover crop mulch on the soil surface. Later oat kill dates were associated with higher natural enemy abundance. Reduced herbicide intensity was associated with (1) lower abundance of several key cabbage (Brassica oleraceae L.) pests, and (2) greater abundance of important natural enemy species. Habitats with both later oat kill dates and reduced herbicide intensity contained (1) fewer herbivores with chewing feeding guilds and more specialized diet breadths, and (2) greater abundance of active hunting natural enemies. Oats reduced cabbage yield when oat kill was delayed past 9-14 DAT. Yields were reduced under low herbicide intensity treatments in 2010 when weed pressure was greatest. We suspect that increased habitat complexity associated with oat mulches and reduced herbicide intensity enhances biological control in cabbage, although caution should be taken to avoid reducing yields or enhancing hyperparasitism. PMID:23575020

Bryant, Alexandria; Brainard, Daniel C; Haramoto, Erin R; Szendrei, Zsofia

2013-04-01

409

Fingerprint recognition of alien invasive weeds based on the texture character and machine learning  

NASA Astrophysics Data System (ADS)

Multi-spectral imaging technique based on texture analysis and machine learning was proposed to discriminate alien invasive weeds with similar outline but different categories. The objectives of this study were to investigate the feasibility of using Multi-spectral imaging, especially the near-infrared (NIR) channel (800 nm+/-10 nm) to find the weeds' fingerprints, and validate the performance with specific eigenvalues by co-occurrence matrix. Veronica polita Pries, Veronica persica Poir, longtube ground ivy, Laminum amplexicaule Linn. were selected in this study, which perform different effect in field, and are alien invasive species in China. 307 weed leaves' images were randomly selected for the calibration set, while the remaining 207 samples for the prediction set. All images were pretreated by Wallis filter to adjust the noise by uneven lighting. Gray level co-occurrence matrix was applied to extract the texture character, which shows density, randomness correlation, contrast and homogeneity of texture with different algorithms. Three channels (green channel by 550 nm+/-10 nm, red channel by 650 nm+/-10 nm and NIR channel by 800 nm+/-10 nm) were respectively calculated to get the eigenvalues.Least-squares support vector machines (LS-SVM) was applied to discriminate the categories of weeds by the eigenvalues from co-occurrence matrix. Finally, recognition ratio of 83.35% by NIR channel was obtained, better than the results by green channel (76.67%) and red channel (69.46%). The prediction results of 81.35% indicated that the selected eigenvalues reflected the main characteristics of weeds' fingerprint based on multi-spectral (especially by NIR channel) and LS-SVM model.

Yu, Jia-Jia; Li, Xiao-Li; He, Yong; Xu, Zheng-Hao

2008-11-01

410

Ozone Exposure of a Weed Community Produces Adaptive Changes in Seed Populations of Spergula arvensis.  

PubMed

Tropospheric ozone is one of the major drivers of global change. This stress factor alters plant growth and development. Ozone could act as a selection pressure on species communities composition, but also on population genetic background, thus affecting life history traits. Our objective was to evaluate the consequences of prolonged ozone exposure of a weed community on phenotypic traits of Spergulaarvensis linked to persistence. Specifically, we predicted that the selection pressure exerted by high ozone concentrations as well as the concomitant changes in the weed community would drive population adaptive changes which will be reflected on seed germination, dormancy and longevity. In order to test seed viability and dormancy level, we conducted germination experiments for which we used seeds produced by S. arvensis plants grown within a weed community exposed to three ozone treatments during four years (0, 90 and 120 ppb). We also performed a soil seed bank experiment to test seed longevity with seeds coming from both the four-year ozone exposure experiment and from a short-term treatment conducted at ambient and added ozone concentrations. We found that prolonged ozone exposure produced changes in seed germination, dormancy and longevity, resulting in three S. arvensis populations. Seeds from the 90 ppb ozone selection treatment had the highest level of germination when stored at 75% RH and 25 °C and then scarified. These seeds showed the lowest dormancy level when being subjected to 5 ºC/5% RH and 25 ºC/75% followed by 5% RH storage conditions. Furthermore, ozone exposure increased seed persistence in the soil through a maternal effect. Given that tropospheric ozone is an important pollutant in rural areas, changes in seed traits due to ozone exposure could increase weed persistence in fields, thus affecting weed-crop interactions, which could ultimately reduce crop production. PMID:24086640

Landesmann, Jennifer B; Gundel, Pedro E; Martínez-Ghersa, M Alejandra; Ghersa, Claudio M

2013-09-26

411

Discriminating Crop, Weeds and Soil Surface with a Terrestrial LIDAR Sensor.  

PubMed

In this study, the evaluation of the accuracy and performance of a light detection and ranging (LIDAR) sensor for vegetation using distance and reflection measurements aiming to detect and discriminate maize plants and weeds from soil surface was done. The study continues a previous work carried out in a maize field in Spain with a LIDAR sensor using exclusively one index, the height profile. The current system uses a combination of the two mentioned indexes. The experiment was carried out in a maize field at growth stage 12-14, at 16 different locations selected to represent the widest possible density of three weeds: Echinochloa crus-galli (L.) P.Beauv., Lamium purpureum L., Galium aparine L.and Veronica persica Poir.. A terrestrial LIDAR sensor was mounted on a tripod pointing to the inter-row area, with its horizontal axis and the field of view pointing vertically downwards to the ground, scanning a vertical plane with the potential presence of vegetation. Immediately after the LIDAR data acquisition (distances and reflection measurements), actual heights of plants were estimated using an appropriate methodology. For that purpose, digital images were taken of each sampled area. Data showed a high correlation between LIDAR measured height and actual plant heights (R2 = 0.75). Binary logistic regression between weed presence/absence and the sensor readings (LIDAR height and reflection values) was used to validate the accuracy of the sensor. This permitted the discrimination of vegetation from the ground with an accuracy of up to 95%. In addition, a Canonical Discrimination Analysis (CDA) was able to discriminate mostly between soil and vegetation and, to a far lesser extent, between crop and weeds. The studied methodology arises as a good system for weed detection, which in combination with other principles, such as vision-based technologies, could improve the efficiency and accuracy of herbicide spraying. PMID:24172283

Andújar, Dionisio; Rueda-Ayala, Victor; Moreno, Hugo; Rosell-Polo, Joan Ramón; Escolá, Alexandre; Valero, Constantino; Gerhards, Roland; Fernández-Quintanilla, César; Dorado, José; Griepentrog, Hans-Werner

2013-10-29

412

Ozone Exposure of a Weed Community Produces Adaptive Changes in Seed Populations of Spergula arvensis  

PubMed Central

Tropospheric ozone is one of the major drivers of global change. This stress factor alters plant growth and development. Ozone could act as a selection pressure on species communities composition, but also on population genetic background, thus affecting life history traits. Our objective was to evaluate the consequences of prolonged ozone exposure of a weed community on phenotypic traits of Spergulaarvensis linked to persistence. Specifically, we predicted that the selection pressure exerted by high ozone concentrations as well as the concomitant changes in the weed community would drive population adaptive changes which will be reflected on seed germination, dormancy and longevity. In order to test seed viability and dormancy level, we conducted germination experiments for which we used seeds produced by S. arvensis plants grown within a weed community exposed to three ozone treatments during four years (0, 90 and 120 ppb). We also performed a soil seed bank experiment to test seed longevity with seeds coming from both the four-year ozone exposure experiment and from a short-term treatment conducted at ambient and added ozone concentrations. We found that prolonged ozone exposure produced changes in seed germination, dormancy and longevity, resulting in three S. arvensis populations. Seeds from the 90 ppb ozone selection treatment had the highest level of germination when stored at 75% RH and 25 °C and then scarified. These seeds showed the lowest dormancy level when being subjected to 5 ºC/5% RH and 25 ºC/75% followed by 5% RH storage conditions. Furthermore, ozone exposure increased seed persistence in the soil through a maternal effect. Given that tropospheric ozone is an important pollutant in rural areas, changes in seed traits due to ozone exposure could increase weed persistence in fields, thus affecting weed-crop interactions, which could ultimately reduce crop production.

Landesmann, Jennifer B.; Gundel, Pedro E.; Martinez-Ghersa, M. Alejandra; Ghersa, Claudio M.

2013-01-01

413

Effect of mechanical weeding on wild chamomile (Matricaria chamomilla L.) populations in winter wheat crop (Triticum aestivum L.).  

PubMed

Currently, economic, agronomic and environmental concerns lead to reduce the use of herbicides. Mechanical weeding can help to reach this objective. Dynamics and biology of wild chamomile (Matricaria chamomilla L.) populations were assessed as well as dynamic of winter wheat (Triticum aestivum L.) for four level of application of a weeder-harrow (0, 1, 2, 3 treatment(s)). After each treatment, an effect of mechanical weeding on wild chamomile density was observed. Density of wild chamomile decreased significantly with intensification of mechanical weeding. A third treatment allowed eliminating late emerged plants. PMID:23878991

Jaunard, D; Bizoux, J P; Monty, A; Henriet, F; De Proft, M; Vancutsem, F; Mahy, G; Bodson, B

2012-01-01

414

Using GIS to Measure the Effectiveness of the Weed and Seed Initiative in Winston-Salem, North Carolina, 2001 - 2007  

Microsoft Academic Search

1. Abstract ,The Weed and Seed program is a Community Capacity Development Office (CCDO) and Department of Justice (DOJ) initiative to revitalize communities,through a holistic approach to law enforcement,and crime prevention. The goal of the Weed & Seed program,is to reduce recidivism and crime by leveraging public and private resources to support the community in the areas of housing, employment,

Timothy Mulrooney; Mike Carmichael

415

Biological and Agricultural Studies on Application of Discharge Plasma and Electromagnetic Fields 4. Destruction of Weeds by High Voltage Discharge  

NASA Astrophysics Data System (ADS)

In an attempt to replace chemicals for weed control, high voltage spark discharge has been applied. With the application of high voltage, discharge takes place, and current flows through the stem and root. Microscopic observation indicates that cells are damaged. The electrical resistance of the damage plant’s stems and roots decreased significantly. Several different types of apparatus were constructed, and field test results show the effectiveness of electrical discharge for weed control.

Mizuno, Akira

416

Allelopathic effect by aqueous extracts of different parts of Croton bonplandianum Baill. on some crop and weed plants  

Microsoft Academic Search

The present study was conducted to investigate the allelopathic effects of Croton bonplandianum weed on seed germination and seedling growth of crop plants (Triticum aestivum L., Brassica oleracea var. botrytis L. and Brassica rapa L.) and weed plants (Melilotus alba Medik., Vicia sativa L. and Medicago hispida Gaertn). Root, stem and leaf aqueous extracts of Croton at 0.5, 1.0, 2.0

Swapnal Sisodia; M. Badruzzaman Siddiqui

417

The Effect of Natural Mulches on Crop Performance, Weed Suppression and Biochemical Constituents of Catnip and St. John's Wort  

PubMed Central

Because of expanding markets for high-value niche crops, opportunities have increased for the production of medicinal herbs in the USA. An experiment was conducted in 2001 and 2002 near Gilbert, IA, to study crop performance, weed suppression, and environmental conditions associated with the use of several organic mulches in the production of two herbs, catnip (Nepeta cataria L.) and St. John’s wort (Hypericum perforatum L. ‘Helos’). Treatments were arranged in a completely randomized design and included a positive (hand-weeded) control, a negative (nonweeded) control, oat straw, a flax straw mat, and a nonwoven wool mat. Catnip plant height was significantly greater in the oat straw than the other treatments at 4 wk through 6 wk in 2001; at 4 to 8 wk in 2002, catnip plant height and width was significantly lower in the negative control compared with the other treatments. Catnip yield was significantly higher in the flax straw mat than all other treatments in 2001. In 2002, St. John’s wort yields were not statistically different in any treatments. All weed management treatments had significantly fewer weeds than the non-weeded rows in 2002. Total weed density comparisons in each crop from 2 yr showed fewer weeds present in the flax straw and wool mat treatments compared with positive control plots. There was no significant weed management treatment effect on the concentration of the target compounds, nepetalactone in catnip and pseudohypericin–hypericin in St. John’s wort, although there was a trend toward higher concentrations in the flax straw treatment.

Duppong, L. M.; Delate, K.; Liebman, M.; Horton, R.; Romero, F.; Kraus, G.; Petrich, J.; Chowdbury, P. K.

2006-01-01

418

A study of weeds as potential inoculum sources for a tomato-infecting begomovirus in central Brazil.  

PubMed

Tomato severe rugose virus (ToSRV) is the most important begomovirus species in Brazilian tomato production. Many weeds are associated with tomato, and some are hosts of begomoviruses. Only one species of weed, Nicandra physaloides, has been found to be infected with ToSRV. In this study, four weed species were investigated for their capacity to be infected by ToSRV and serve as a potential source of inoculum for tomato. Begomoviruses from naturally infected Crotalaria spp., Euphorbia heterophylla, N. physaloides, and Sida spp. were successfully transferred to tomato plants by biolistic inoculation. ToSRV was the major virus transferred to tomato. In contrast, other begomoviruses were transferred to weeds, such as Sida micrantha mosaic virus and Euphorbia yellow mosaic virus. Furthermore, a new strain of Sida micrantha mosaic virus is reported. We also confirmed that Crotalaria spp., E. heterophylla, and Sida spp. are infected with ToSRV but at low viral titers and in mixed infections with weed-infecting begomoviruses. Thus, it was demonstrated that weeds are potential sources of ToSRV for tomato in central Brazil. PMID:23489523

Barreto, S S; Hallwass, M; Aquino, O M; Inoue-Nagata, A K

2013-05-01

419

Bonneville Power Administration, Lower Columbia Region: Noxious Weed Management, 1996 Annual Report.  

SciTech Connect

During the 1996 season ODA executed the contract between BPA and ODA. Execution of this contract included the following activities: Survey for target noxious weeds, such as Gorse; collection and redistribution of biological control agents, for example, Apion seed weevils for Scotch broom, bioagents for diffuse and spotted knapweed, Gorse spider mite, and gall fly releases for control of Canada thistle and bull thistle; and control of isolated infestations of Gorse on BPA rights-of-way. Training was provided for line crews at the Chemawa, Alevy and North Bend districts. The purpose of the program is to assist BPA in the integrated prevention and control of noxious weed species on BPA transmission line maintenance right-of-ways.

United States. Bonneville Power Administration, Portland, OR; Oregon Department of Agriculture Noxious Weed Control Program

1996-01-01

420

USE OF AIRBORNE MULTISPECTRAL IMAGERY FOR WEED DETECTION IN FIELD CROPS  

Microsoft Academic Search

In this article, the potential of multi-spectral airborne remote sensing is evaluated for the detection of weed infestation in corn (Zea mays L.) and soybean (Glycine max.) crops. A field plot experiment was laid out at the Lods Agronomy Research Center of Macdonald Campus, McGill University, Ste-Anne-de-Bellevue, Quebec, Canada. A multi-spectral image in 24 wavebands (475.12 nm to 910.01 nm

P. K. Goel; S. O. Prasher; R. M. Patel; D. L. Smith; A. DiTommaso

421

Morphological responses of crop and weed species of different growth forms to ultraviolet-B radiation  

Microsoft Academic Search

Recent evidence of a general, global decline of stratospheric ozone has heightened concern about possible ecological consequences of increases in solar ultraviolet-B (UV-B, 280-320 nm) radiation resulting from ozone depletion. The influence of UV-B radiation (280-320 nanometers) on the morphology of 12 common dicot and monocot crop or weed species was examined to determine whether any common responses could be

Paul W. Barnes; Stephan D. Flint; Martyn M. Caldwell

1990-01-01

422

The effects of Phoma macrostoma on nontarget plant and target weed species  

Microsoft Academic Search

Phoma macrostoma 94-44B was evaluated against 94 plant species in 34 botanical families, of economically important agricultural, horticultural and ornamental species, as well as target and nontarget weeds. Fifty-seven species from 28 families were found to be resistant to P. macrostoma, while 38 species from 12 families, six of which also contained resistant species, were found to be susceptible. Those

K. L. Bailey; W. M. Pitt; S. Falk; J. Derby

2011-01-01

423

Predictability of pathogen host range in classical biological control of weeds: an update  

Microsoft Academic Search

Before an exotic pathogen can be released as a classical biological control agent the likely positive and negative outcomes\\u000a of that introduction must be predicted. Host range testing is used to assess potential damage to non-target plants. To-date\\u000a 28 species of fungi have been released as classical biological control agents against weeds world-wide. These pathogens have\\u000a been reported infecting only

Jane Barton

424

Soilborne microorganisms of Euphorbia are potential biological control agents of the invasive weed leafy spurge  

Microsoft Academic Search

Leafy spurge (Euphorbia esula-virgata), a native of Eurasia, is a serious invasive weed of grasslands of the northern Great Plains of the U.S. and prairie provinces of Canada. Leafy spurge is very difficult to control with herbicides, insect biological control agents, and other cultural practices. Previous field investigations revealed pathogen–insect interactions on the roots of leafy spurge leading to mortality.

Robert J. Kremer; Anthony J. Caesar; Thouraya Souissi

2006-01-01

425

STRATEGIES FOR EXPANDING AND IMPROVING OVERSEAS RESEARCH FOR BIOLOGICAL CONTROL OF WEEDS  

Microsoft Academic Search

The followmg recornmendat~ons are made to Improve overseas research on blolog~cal control agents Conduct more long-term overseas evaluations Place much greater emphasis on field host range studies Carry out more research on Impact and efficacy of potential agents Perform more ecological research overseas on target weed Adhere to lnternatlonal standards for b~olog~ca~control stud^& Document all findings including fallures NEED FOR

Joe Balciunas

426

Erythema multiforme due to contact with weeds: a recurrence after patch testing.  

PubMed

Erythema multiforme (EM) as a complication of patch testing (PT) is rare. A 52-year-old woman with a 13-year history of episodes of EM, after contact with weeds during home gardening, had had no recent history of herpes simplex, other infection, drug ingestion or vaccination. On examination, EM lesions were distributed on the exposed skin. 5 weeks after complete resolution, PT and photopatch testing (PPT) were done with fresh plants she brought in. She was PT with a standard series and the Hermal-Trolab plants, woods, tars, balsams and flavors series. Intradermal testing, with a 3 + reaction to mixed weed pollens, was done 3 weeks later. Specific IgE to weed pollens class 1 (CAP-Pharmacia) was detected. Eczematous PT reactions were obtained with fresh leaves: common chickweed (Stellaria media Caryophyllaceae), dandelion (Taraxacum officinale Compositae), field-milk thistle (Sonchus arvensis Compositae) and white clover (Trifolium repens Leguminosae). Photoaggravation was seen to common chickweed and dandelion. Positive PT was also seen with alantolactone. By the 4-day reading, a typical EM had commenced, coming up to quite the same extent as seen on admission. There was no photosensitivity (UV skin tester, K. Waldmann). In the essential oil obtained from common chickweed, thin layer chromatography (TLC) revealed the well-known contact allergens borneol, menthol, linalool, 1,8-cineole, and other terpenes such as epoxy-dehydro-caryophyllene, monoterpene alcohol-ester and caryophyllene. Up to now, no data on essential oil in Stellaria media (common chickweed) have been reported. It can be concluded that EM developed due to contact with weeds, and recurred after patch testing. Neither blistering nor eczematous lesions have been seen on her skin, making this case very unusual. As far as the world literature is concerned, this is only the 4th report of EM developing in association with patch testing. PMID:12641574

Jovanovi?, M; Mimica-Duki?, N; Poljacki, M; Boza, P

2003-01-01

427

Modelling Weed Distribution Across the Northern Australia Using Very Extensive Transects  

Microsoft Academic Search

\\u000a A Generalised Additive Modelling (GAM) approach is used to predict weed occurrence across the Top End of the Northern Territory,\\u000a Australia. The availability of new toolsets such as GRASP (Generalised Regression Analysis and Spatial Predictions) and the\\u000a application of novel GIS variables, including remotely sensed Radiometric data, Infrastructure density (roads and fences)\\u000a mapping and Climate layers, provide a useful framework

C. Hempel; N. Preece; K. Harvey; J. C. Z. Woinarski

428

Time of Weed Removal with Glyphosate Affects Corn Growth and Yield Components  

Microsoft Academic Search

Growers need to be aware that corn (Zea mays L.) develops leaf area slowly and competes poorly with early emerging weeds in the northeastern USA when planning a total postemergence program in glyphosate-resistant corn. We applied glyphosate at early postemer- gence (EPOST), third to fourth leaf stage (V3-V4) of corn growth; mid-postemergence (MPOST), V5 to V6 stage; and late postemer-

William J. Cox; Russell R. Hahn; Paul J. Stachowski

2006-01-01

429

WEED SCIENCE Response of Glyphosate-resistant Cotton to Pre-harvest Glyphosate Application  

Microsoft Academic Search

Growers of glyphosate-resistant (GR) cotton (Gossypium hirsutum L.) often apply glyphosate postemergence over-the-top (POST) late in the season to control escaped weeds and to increase harvesting efficiency. Labels for glyphosate prod - ucts currently permit such applications only after the 20% cracked-boll stage, which is later than most growers want to apply the glyphosate. An experiment was conducted eight times

Alexander M. Stewart; Alan C. York; A. Stanley Culpepper; P. Roy Vidrine

2005-01-01

430

Chromium Removal from Soil by Phytoremediation with Weed Plant Species in Thailand  

Microsoft Academic Search

The possibility of using phytoremediation with weed plant species in Thailand to remove chromium (Cr) from soil was investigated.\\u000a Six plant species, Cynodon dactylon, Pluchea indica, Phyllanthus reticulatus, Echinochloa colonum, Vetiveria nemoralis, and Amaranthus viridis, were chosen for their abilities to accumulate total chromium (TCr) at tanning industry sites. These plant species were studied\\u000a in pots at a nursery. Cynodon

Pantawat Sampanpanish; Wasant Pongsapich; Sutha Khaodhiar; Eakalak Khan

2006-01-01

431

The potential global distribution of the invasive weed Nassella neesiana under current and future climates  

Microsoft Academic Search

Nassella neesiana (Trin. and Rupr.) (Chilean needle grass), native to South America, has naturalised sporadically in the UK, France, Italy\\u000a and Spain, and more widely in Australia and New Zealand, where it has become a serious grassland weed. As a first step towards\\u000a a global risk analysis we project a CLIMEX model of N. neesiana distribution globally under current climate

Graeme W. BourdotShona; Shona L. Lamoureaux; Michael S. Watt; Lucy K. Manning; Darren J. Kriticos

432

Real-time image processing for crop\\/weed discrimination in maize fields  

Microsoft Academic Search

This paper presents a computer vision system that successfully discriminates between weed patches and crop rows under uncontrolled lighting in real-time. The system consists of two independent subsystems, a fast image processing delivering results in real-time (Fast Image Processing, FIP), and a slower and more accurate processing (Robust Crop Row Detection, RCRD) that is used to correct the first subsystem’s

Xavier P. Burgos-Artizzu; Angela Ribeiro; Maria Guijarro; Gonzalo Pajares

2011-01-01

433

Two compounds from allelopathic rice accession and their inhibitory activity on weeds and fungal pathogens  

Microsoft Academic Search

A flavone (5,7,4?-trihydroxy-3?,5?-dimethoxyflavone), a cyclohexenone (3-isopropyl-5-acetoxycyclohexene-2-one-1) and a liquid mixture of low polarity, containing long-chain and cyclic hydrocarbons, were isolated from leaves of allelopathic rice accession PI 312777 using column chromatography. Their structures and constituents were identified by means of HR-MS, NMR and GC\\/MS analyses, respectively. Bioassays showed that both the flavone and cyclohexenone significantly inhibited the growth of weeds

Chuihua Kong; Xiaohua Xu; Bin Zhou; Fei Hu; Chaoxian Zhang; Maoxin Zhang

2004-01-01

434

Does allelopathy explain the invasiveness of Campuloclinium macrocephalum (pompom weed) in the South African grassland biome?  

Microsoft Academic Search

Campuloclinium macrocephalum is an Asteraceous alien weed that invades roadside vegetation and grassland in South Africa. The role of allelopathy and\\u000a competition in its invasiveness was investigated using Eragrostis curvula (weeping lovegrass, an indigenous grass), E. tef and Lactuca sativa (lettuce) as test species. Trials were conducted in Petri-dishes, pots and in the field. Root and shoot extracts of adult

Jeremy GoodallEd; Ed T. F. Witkowski; Sigrun Ammann; Carl Reinhardt

2010-01-01

435

Key role for a glutathione transferase in multiple-herbicide resistance in grass weeds  

PubMed Central

Multiple-herbicide resistance (MHR) in black-grass (Alopecurus myosuroides) and annual rye-grass (Lolium rigidum) is a global problem leading to a loss of chemical weed control in cereal crops. Although poorly understood, in common with multiple-drug resistance (MDR) in tumors, MHR is associated with an enhanced ability to detoxify xenobiotics. In humans, MDR is linked to the overexpression of a pi class glutathione transferase (GSTP1), which has both detoxification and signaling functions in promoting drug resistance. In both annual rye-grass and black-grass, MHR was also associated with the increased expression of an evolutionarily distinct plant phi (F) GSTF1 that had a restricted ability to detoxify herbicides. When the black-grass A. myosuroides (Am) AmGSTF1 was expressed in Arabidopsis thaliana, the transgenic plants acquired resistance to multiple herbicides and showed similar changes in their secondary, xenobiotic, and antioxidant metabolism to those determined in MHR weeds. Transcriptome array experiments showed that these changes in biochemistry were not due to changes in gene expression. Rather, AmGSTF1 exerted a direct regulatory control on metabolism that led to an accumulation of protective flavonoids. Further evidence for a key role for this protein in MHR was obtained by showing that the GSTP1- and MDR-inhibiting pharmacophore 4-chloro-7-nitro-benzoxadiazole was also active toward AmGSTF1 and helped restore herbicide control in MHR black-grass. These studies demonstrate a central role for specific GSTFs in MHR in weeds that has parallels with similar roles for unrelated GSTs in MDR in humans and shows their potential as targets for chemical intervention in resistant weed management.

Cummins, Ian; Wortley, David J.; Sabbadin, Federico; He, Zhesi; Coxon, Christopher R.; Straker, Hannah E.; Sellars, Jonathan D.; Knight, Kathryn; Hughes, David; Kaundun, Shiv Shankhar; Hutchings, Sarah-Jane; Steel, Patrick G.; Edwards, Robert

2013-01-01

436

Broadleaved weed control in wide-row soybean ( Glycine max) using conventional and glyphosate herbicide programmes  

Microsoft Academic Search

A field study was conducted in 2001 and 2002 at Blackville, SC, to evaluate broadleaved weed control and economics of conventional and glyphosate-containing herbicide programmes in glyphosate-resistant soybean planted in 97-cm-wide rows. Treatments included chlorimuron plus sulfentrazone or chlorimuron plus metribuzin applied pre-emergence followed by post-emergence applications of lactofen or glyphosate 4wk after soybean emergence (WAE). Other treatments were glyphosate

Jason K. Norsworthy

2004-01-01

437

Improved weed control with broadleaved herbicides in glyphosate-tolerant soybean ( Glycine max)  

Microsoft Academic Search

Failure to control certain broadleaved weeds with glyphosate creates the need for other herbicides in glyphosate-tolerant soybean. Field studies were conducted in 2001, 2002 and 2003 to evaluate soybean yield response and control of Solanum sisymbrifolium Lam., Parietaria debilis Nutt., Commelina erecta L. and Sida rhombifolia L. with soil and foliar-applied broadleaved herbicides. Pre-emergence metribuzin, imazaquin and post-emergence imazethapyr and

María C. Arregui; Roberto Scotta; Daniel Sánchez

2006-01-01

438

Host specificity of the Asian weevil, Rhinoncomimus latipes Korotyaev (Coleoptera: Curculionidae), a potential biological control agent of mile-a-minute weed, Polygonum perfoliatum L. (Polygonales: Polygonaceae)  

Microsoft Academic Search

The annual vine Polygonum perfoliatum L. (mile-a-minute weed) is an invasive weed in natural areas and has been targeted for biological control in the United States. Host specificity of the Asian weevil Rhinoncomimus latipes Korotyaev, a potential biological control agent of mile-a-minute weed, was evaluated in China using qualitative laboratory choice and no-choice tests on 28 plant species in 18

Keith Colpetzer; Judith Hough-Goldstein; Jianqing Ding; Weidong Fub

2004-01-01

439

Weed control and wheat ( Triticum aestivum L.) yield under application of 2,4-D plus carfentrazone-ethyl and florasulam plus flumetsulam: Evaluation of the efficacy  

Microsoft Academic Search

Three field experiments were conducted at the research fields of Plant Protection Research Institute, Iran, at different locations in 2004–2005 to study the efficacy of different broadleaved herbicides to control weeds in wheat. Treatments were the full-season hand weeded and weed-infested controls, and post-emergence applications of florasulam plus flumetsulam at 8.75, 10.50, and 12.25ga.i.\\/ha, 2,4-D plus carfentrazone-ethyl at 210, 245,

Mohammad Ali Baghestani; Eskandar Zand; Saeid Soufizadeh; Naser Bagherani; Reza Deihimfard

2007-01-01

440

Glyphosate degradation in glyphosate-resistant and -susceptible crops and weeds.  

PubMed

High levels of aminomethylphosphonic acid (AMPA), the main glyphosate metabolite, have been found in glyphosate-treated, glyphosate-resistant (GR) soybean, apparently due to plant glyphosate oxidoreductase (GOX)-like activity. AMPA is mildly phytotoxic, and under some conditions the AMPA accumulating in GR soybean correlates with glyphosate-caused phytotoxicity. A bacterial GOX is used in GR canola, and an altered bacterial glyphosate N-acetyltransferase is planned for a new generation of GR crops. In some weed species, glyphosate degradation could contribute to natural resistance. Neither an isolated plant GOX enzyme nor a gene for it has yet been reported in plants. Gene mutation or amplification of plant genes for GOX-like enzyme activity or horizontal transfer of microbial genes from glyphosate-degrading enzymes could produce GR weeds. Yet, there is no evidence that metabolic degradation plays a significant role in evolved resistance to glyphosate. This is unexpected, considering the extreme selection pressure for evolution of glyphosate resistance in weeds and the difficulty in plants of evolving glyphosate resistance via other mechanisms. PMID:20919737

Duke, Stephen O

2010-10-04

441

Composition and diversity of weed communities in Al-Jouf province, northern Saudi Arabia  

PubMed Central

The aim of this study was to identify the main weed communities in Al-Jouf province in northern Saudi Arabia. Moreover, the composition and diversity of these communities were studied in relation to soil variables and crop type. Some 54 stands representing olive orchards, date palm orchards, wheat crop and watermelon crop were studied, using ten quadrats (1 × 1 m) per stand. A total of 71 species belonging to 22 families and 61 genera were observed. The classification of vegetation using the Two Way Indicator Species Analysis (TWINSPAN) resulted in the recognition of four vegetation groups representing wheat crop, orchards in winter season, orchards in summer season and watermelon crop. These results suggested the importance of both crop and season for the formation of weed community. Detrended Correspondence Analysis (DCA) showed that these groups are clearly distinguished by the first two DCA axes. The species richness was higher in both olive and date palm orchards than in wheat and watermelon crops. This pattern of species richness could be related to farm management practices and habitat micro-heterogeneity. Soil electrical conductivity, organic carbon and soil texture showed significant correlations with species richness and the cover values of some dominant species, suggesting the significant role of soil characteristics in weed community structure and diversity.

Gomaa, Nasr H.

2012-01-01

442

The mechanism of methylated seed oil on enhancing biological efficacy of topramezone on weeds.  

PubMed

Methylated seed oil (MSO) is a recommended adjuvant for the newly registered herbicide topramezone in China and also in other countries of the world, but the mechanism of MSO enhancing topramezone efficacy is still not clear. Greenhouse and laboratory experiments were conducted to determine the effects of MSO on efficacy, solution property, droplet spread and evaporation, active ingredient deposition, foliar absorption and translocation of topramezone applied to giant foxtail (Setaria faberi Herrm.) and velvetleaf (Abutilon theophrasti Medic.). Experimental results showed that 0.3% MSO enhanced the efficacy of topramezone by 1.5-fold on giant foxtail and by 1.0-fold on velvetleaf. When this herbicide was mixed with MSO, its solution surface tension and leaf contact angle decreased significantly, its spread areas on weed leaf surfaces increased significantly, its wetting time was shortened on giant foxtail but not changed on velvetleaf, and less of its active ingredient crystal was observed on the treated weed leaf surfaces. MSO increased the absorption of topramezone by 68.9% for giant foxtail and by 45.9% for velvetleaf 24 hours after treatment. It also apparently promoted the translocation of this herbicide in these two weeds. PMID:24086329

Zhang, Jinwei; Jaeck, Ortrud; Menegat, Alexander; Zhang, Zongjian; Gerhards, Roland; Ni, Hanwen

2013-09-24

443

Weeds: a CLASS extension for the analysis of millimeter and sub-millimeter spectral surveys  

NASA Astrophysics Data System (ADS)

The advent of large instantaneous bandwidth receivers and high spectral resolution spectrometers on (sub-)millimeter telescopes has opened up the possibilities for unbiased spectral surveys. Because of the large amount of data they contain, any analysis of these surveys requires dedicated software tools. Here we present an extension of the widely used CLASS software that we developed to that purpose. This extension, named Weeds, allows for searches in atomic and molecular lines databases (e.g. JPL or CDMS) that may be accessed over the internet using a virtual observatory (VO) compliant protocol. The package permits a quick navigation across a spectral survey to search for lines of a given species. Weeds is also capable of modeling a spectrum, as often needed for line identification. We expect that Weeds will be useful for analyzing and interpreting the spectral surveys that will be done with the HIFI instrument onboard Herschel, but also observations carried-out with ground based millimeter and sub-millimeter telescopes and interferometers, such as IRAM-30 m and Plateau de Bure, CARMA, SMA, eVLA, and ALMA.

Maret, S.; Hily-Blant, P.; Pety, J.; Bardeau, S.; Reynier, E.

2011-02-01

444

Development of a guideline on vegetation area to reduce the risk of weed pollinosis in Korea  

NASA Astrophysics Data System (ADS)

Allergenic pollens are influenced by the environmental conditions so that the daily number of pollens varies by temperature, humidity, wind speed, etc. The relationship between the daily pollens and meteorological conditions were determined and utilized to forecast daily risk level of pollen allergy in Korea. Another important factor for the daily risk level of pollens is the vegetation area of the allergenic plants. In this study, the relationship between the area and pollen concentration was identified for two major weed species: Ragweed and Japanese Hop. It was then utilized to determine the upper limit of vegetation area to confine the risk level to a certain degree in the field. Three sites with different levels of pollen concentration were selected among twelve pollen observation sites in Korea based on the historical observation of the weed pollens. The vegetation area of the two weed species within four square kilometers at each site was surveyed. The maximum daily pollen concentration was highly correlated with the vegetation area and it was selected as a dependent variable for the regression equations, which were used as the guideline for vegetation area. According to the guideline, to limit the maximum daily pollen concentration under the moderate risk level or less than 50 pollen grains per cubic meter for Ragweed, the vegetation area should remain less than 0.6% of the ground area. For the moderate risk of Japanese Hop, pollen grains should be limited less than 100 and the area be less than 0.4%.

Rang Kim, Kyu; Lee, Hye-Rim; Kim, Mijin; Baek, Won-ki; Oh, Jae-Won; Choi, Young-Jean; Jung, Hyun-Sook

2013-04-01

445

Composition and diversity of weed communities in Al-Jouf province, northern Saudi Arabia.  

PubMed

The aim of this study was to identify the main weed communities in Al-Jouf province in northern Saudi Arabia. Moreover, the composition and diversity of these communities were studied in relation to soil variables and crop type. Some 54 stands representing olive orchards, date palm orchards, wheat crop and watermelon crop were studied, using ten quadrats (1 × 1 m) per stand. A total of 71 species belonging to 22 families and 61 genera were observed. The classification of vegetation using the Two Way Indicator Species Analysis (TWINSPAN) resulted in the recognition of four vegetation groups representing wheat crop, orchards in winter season, orchards in summer season and watermelon crop. These results suggested the importance of both crop and season for the formation of weed community. Detrended Correspondence Analysis (DCA) showed that these groups are clearly distinguished by the first two DCA axes. The species richness was higher in both olive and date palm orchards than in wheat and watermelon crops. This pattern of species richness could be related to farm management practices and habitat micro-heterogeneity. Soil electrical conductivity, organic carbon and soil texture showed significant correlations with species richness and the cover values of some dominant species, suggesting the significant role of soil characteristics in weed community structure and diversity. PMID:23961198

Gomaa, Nasr H

2012-05-14

446

Uptake, translocation and metabolism of the herbicide florasulam in wheat and broadleaf weeds.  

PubMed

Florasulam is a triazolopyrimidine sulfonanilide post-emergence broadleaf herbicide for use in wheat (Triticum aestivum L.). The selectivity of florasulam to wheat has been determined to be related primarily to a differential rate of metabolism between wheat with a half-life of 2.4 h and broadleaf weeds with half-lives ranging from 19 to >48 h. To a lesser extent, selectivity, at least for the broadleaf weed cleavers (Galium aparine L.), involves uptake differences. Rate of metabolism data were generated using greenhouse-grown plants injected with radiolabelled florasulam and subsequent extraction and processing by high-performance liquid chromatography (HPLC). Structures of metabolites were determined by isolation for nuclear magnetic resonance and liquid chromatography/mass spectrometry. Wheat plants metabolised florasulam by hydroxylation of the aniline ring para to the nitrogen, followed by conjugation to glucose. Metabolism by broadleaf weeds was so slow that isolation of metabolite was not possible, but comparison of HPLC data suggested hydroxylation as the major pathway. PMID:16506146

deBoer, Gerrit J; Thornburgh, Scott; Ehr, Robert J

2006-04-01

447

The Mechanism of Methylated Seed Oil on Enhancing Biological Efficacy of Topramezone on Weeds  

PubMed Central

Methylated seed oil (MSO) is a recommended adjuvant for the newly registered herbicide topramezone in China and also in other countries of the world, but the mechanism of MSO enhancing topramezone efficacy is still not clear. Greenhouse and laboratory experiments were conducted to determine the effects of MSO on efficacy, solution property, droplet spread and evaporation, active ingredient deposition, foliar absorption and translocation of topramezone applied to giant foxtail (Setaria faberi Herrm.) and velvetleaf (Abutilon theophrasti Medic.). Experimental results showed that 0.3% MSO enhanced the efficacy of topramezone by 1.5-fold on giant foxtail and by 1.0-fold on velvetleaf. When this herbicide was mixed with MSO, its solution surface tension and leaf contact angle decreased significantly, its spread areas on weed leaf surfaces increased significantly, its wetting time was shortened on giant foxtail but not changed on velvetleaf, and less of its active ingredient crystal was observed on the treated weed leaf surfaces. MSO increased the absorption of topramezone by 68.9% for giant foxtail and by 45.9% for velvetleaf 24 hours after treatment. It also apparently promoted the translocation of this herbicide in these two weeds.

Zhang, Jinwei; Jaeck, Ortrud; Menegat, Alexander; Zhang, Zongjian; Gerhards, Roland; Ni, Hanwen

2013-01-01

448

Benzoxazinoids in rye allelopathy - from discovery to application in sustainable weed control and organic farming.  

PubMed

The allelopathic potency of rye (Secale cereale L.) is due mainly to the presence of phytotoxic benzoxazinones-compounds whose biosynthesis is developmentally regulated, with the highest accumulation in young tissue and a dependency on cultivar and environmental influences. Benzoxazinones can be released from residues of greenhouse-grown rye at levels between 12 and 20 kg/ha, with lower amounts exuded by living plants. In soil, benzoxazinones are subject to a cascade of transformation reactions, and levels in the range 0.5-5 kg/ha have been reported. Starting with the accumulation of less toxic benzoxazolinones, the transformation reactions in soil primarily lead to the production of phenoxazinones, acetamides, and malonamic acids. These reactions are associated with microbial activity in the soil. In addition to benzoxazinones, benzoxazolin-2(3H)-one (BOA) has been investigated for phytotoxic effects in weeds and crops. Exposure to BOA affects transcriptome, proteome, and metabolome patterns of the seedlings, inhibits germination and growth, and can induce death of sensitive species. Differences in the sensitivity of cultivars and ecotypes are due to different species-dependent strategies that have evolved to cope with BOA. These strategies include the rapid activation of detoxification reactions and extrusion of detoxified compounds. In contrast to sensitive ecotypes, tolerant ecotypes are less affected by exposure to BOA. Like the original compounds BOA and MBOA, all exuded detoxification products are converted to phenoxazinones, which can be degraded by several specialized fungi via the Fenton reaction. Because of their selectivity, specific activity, and presumably limited persistence in the soil, benzoxazinoids or rye residues are suitable means for weed control. In fact, rye is one of the best cool season cover crops and widely used because of its excellent weed suppressive potential. Breeding of benzoxazinoid resistant crops and of rye with high benzoxazinoid contents, as well as a better understanding of the soil persistence of phenoxazinones, of the weed resistance against benzoxazinoids, and of how allelopathic interactions are influenced by cultural practices, would provide the means to include allelopathic rye varieties in organic cropping systems for weed control. PMID:23385365

Schulz, Margot; Marocco, Adriano; Tabaglio, Vincenzo; Macias, Francisco A; Molinillo, Jose M G

2013-02-06

449

DNA Analysis of Herbarium Specimens of the Grass Weed Alopecurus myosuroides Reveals Herbicide Resistance Pre-Dated Herbicides.  

PubMed

Acetyl-CoA carboxylase (ACCase) alleles carrying one point mutation that confers resistance to herbicides have been identified in arable grass weed populations where resistance has evolved under the selective pressure of herbicides. In an effort to determine whether herbicide resistance evolves from newly arisen mutations or from standing genetic variation in weed populations, we used herbarium specimens of the grass weed Alopecurus myosuroides to seek mutant ACCase alleles carrying an isoleucine-to-leucine substitution at codon 1781 that endows herbicide resistance. These specimens had been collected between 1788 and 1975, i.e., prior to the commercial release of herbicides inhibiting ACCase. Among the 734 specimens investigated, 685 yielded DNA suitable for PCR. Genotyping the ACCase locus using the derived Cleaved Amplified Polymorphic Sequence (dCAPS) technique identified one heterozygous mutant specimen that had been collected in 1888. Occurrence of a mutant codon encoding a leucine residue at codon 1781 at the heterozygous state was confirmed in this specimen by sequencing, clearly demonstrating that resistance to herbicides can pre-date herbicides in weeds. We conclude that point mutations endowing resistance to herbicides without having associated deleterious pleiotropic effects can be present in weed populations as part of their standing genetic variation, in frequencies higher than the mutation frequency, thereby facilitating their subsequent selection by herbicide applications. PMID:24146749

Délye, Christophe; Deulvot, Chrystel; Chauvel, Bruno

2013-10-16

450

DNA Analysis of Herbarium Specimens of the Grass Weed Alopecurus myosuroides Reveals Herbicide Resistance Pre-Dated Herbicides  

PubMed Central

Acetyl-CoA carboxylase (ACCase) alleles carrying one point mutation that confers resistance to herbicides have been identified in arable grass weed populations where resistance has evolved under the selective pressure of herbicides. In an effort to determine whether herbicide resistance evolves from newly arisen mutations or from standing genetic variation in weed populations, we used herbarium specimens of the grass weed Alopecurus myosuroides to seek mutant ACCase alleles carrying an isoleucine-to-leucine substitution at codon 1781 that endows herbicide resistance. These specimens had been collected between 1788 and 1975, i.e., prior to the commercial release of herbicides inhibiting ACCase. Among the 734 specimens investigated, 685 yielded DNA suitable for PCR. Genotyping the ACCase locus using the derived Cleaved Amplified Polymorphic Sequence (dCAPS) technique identified one heterozygous mutant specimen that had been collected in 1888. Occurrence of a mutant codon encoding a leucine residue at codon 1781 at the heterozygous state was confirmed in this specimen by sequencing, clearly demonstrating that resistance to herbicides can pre-date herbicides in weeds. We conclude that point mutations endowing resistance to herbicides without having associated deleterious pleiotropic effects can be present in weed populations as part of their standing genetic variation, in frequencies higher than the mutation frequency, thereby facilitating their subsequent selection by herbicide applications.

Delye, Christophe; Deulvot, Chrystel; Chauvel, Bruno

2013-01-01

451

If You Build It (and Weed It and Promote It), They Will Come: Increasing Circulation of a Fiction Collection at an All-Boys High School  

Microsoft Academic Search

This case study of an all-boys high school library examined fiction collection circulation and methods of increasing book check-outs. The purpose of this study was to determine if weeding, collection improvement, and fiction placement and display are effective methods for increasing circulation of a fiction collection for teenage boys. Circulation and collection data were analyzed to provide assistance in weeding.

Jessica Tipton

2011-01-01

452

Avoiding conflicts between insect and weed biological control: selection of non-target species to assess host specificity of cabbage seedpod weevil parasitoids  

Microsoft Academic Search

Classical biological control of insect pests and weeds may lead to potential conflicts, where insect pests are closely related to weed biological control agents. Such a conflict may occur in the classical biological control of the cabbage seedpod weevil, Ceutorhynchus obstrictus (Marsham) in North America, which belongs to the same subfamily, Ceutorhynchinae, as a number of agents introduced or proposed

U. Kuhlmann; P. G. Mason; H. L. Hinz; B. Blossey; R. A. De Clerck-Floate; L. M. Dosdall; J. P. McCaffrey; M. Schwarzlaender; O. Olfert; J. Brodeur; A. Gassmann; A. S. McClay; R. N. Wiedenmann

2006-01-01

453

Structure?Activity Relationship (SAR) Studies of Benzoxazinones, Their Degradation Products, and Analogues. Phytotoxicity on Problematic Weeds Avena fatua L. and Lolium rigidum Gaud  

Microsoft Academic Search

Avena fatua L. (wild oat) and Lolium rigidum Gaud. (rigid ryegrass) are highly problematic weeds affecting a wide variety of cereal crops worldwide. The fact that both of these weeds have developed resistance to several herbicide groups made them optimal candidates as target organisms for ongoing research about the potential application of allelochemicals and analogue compounds as natural herbicide models.

Francisco A. Macías; David Marín; Alberto Oliveros-Bastidas; Diego Castellano; Ana M. Simonet; José M. G. Molinillo

2006-01-01

454

Impact of rubber tree planting pattern on Imperata cylindrica dynamics - Exploring weed control through shading using SExI-FS, a forest stand simulator  

Microsoft Academic Search

SUMMARY Imperata cylindrica ((L.) Beauv.) is a problem weed throughout tropical and subtropical regions of the world. It is a major impediment to reforestation efforts in Southeast Asia. When rubber ( Hevea brasiliensis ) is planted in areas invaded with Imperata , this aggressive light-demanding weed very much delays the growth of young rubber trees through competition (Mulyoutami et al.

Degi Harja; Gregoire Vincent; Pratiknyo Purnomosidhi; Subekti Rahayu; Laxman Joshi

455

PROCEEDINGS OF THE WORKSHOP ON AQUATIC WEEDS: CONTROL AND ITS ENVIRONMENTAL CONSEQUENCES HELD AT GULF BREEZE, FLORIDA ON FEBRUARY 25-26, 1980  

EPA Science Inventory

The report reviews the state-of-the-art of the chemical, biological, mechanical, and integrated control of aquatic weeds. Participants discuss problems in the field of aquatic weed control and the role of EPA in working toward their solution. Guidelines are proposed for the evalu...

456

Germination of pollen of weed rye ( Secale segetale L.) on wheat ( Triticum aestivum L.) stigmas and the growth of the pollen tubes  

Microsoft Academic Search

Summary Two gene pairs have been found regulating the crossability of wheat and rye. It is concluded from our work that the same genes regulate crossability between wheat and weed rye. The crossing barrier was not observed in the stigma, style or ovary wall because pollen tubes of weed rye were seen in these tissues irrespective of the wheat variety

A. C. Zeven; C. van Heemert

1970-01-01

457

Enhancement in the Efficiency of Existing Oxidation Ponds by Using Aquatic Weeds at Little or No Extra Cost—The Macrophyte-Upgraded Oxidation Pond (MUOP)  

Microsoft Academic Search

All over the world, tens of thousands of oxidation ponds are in operation treating sewage and other biodegradable wastewaters. The performance of such ponds can be greatly enhanced if certain aquatic weeds are held in them. The weeds enable better treatment of wastewater in terms of greater reduction in the biochemical oxygen demand (BOD), suspended solids, nitrogen, phosphorous, metals, etc.,

Tasneem Abbasi; S. A. Abbasi

2010-01-01

458

Einfluss von lebenden Mulchen auf die Begleitflora und die Weizenerträge unter Bedingungen des Ökolandbaus Impact of living mulches on weeds and yield of winter wheat in organic farming  

Microsoft Academic Search

For the success of no-tillage in organic farming, new tools have to be developed to control weeds. One possible strategy could be sowing the main crop into an earlier established living mulch of easily controllable cover crops. Field trials were carried out in the Swiss midlands to investigate the impact of different legume cover crops on weed populations and grain

J. Hiltbrunner; M. Liedgens; P. Stamp; B. Streit

459

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

PubMed

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

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

2012-12-21

460

Complex interactions among biocontrol agents, pollinators, and an invasive weed: a structural equation modeling approach.  

PubMed

Herbivores, seed predators, and pollinators can exert strong impacts on their host plants. They can also affect the strength of each other's impact by modifying traits in their shared host, producing super- or sub-additive outcomes. This phenomenon is especially relevant to biological control of invasive plants because most invaders are attacked by multiple agents. Unfortunately, complex interactions among agents are rarely studied. We used structural equation modeling (SEM) to quantify the effect of two biocontrol agents and generalist pollinators on the invasive weed Centaurea solstitialis, and to identify and quantify the direct and indirect interaction pathways among them. The weevil Eustenopus villosus is both a bud herbivore and a predispersal seed predator; the fly Chaetorellia succinea is also a predispersal seed predator; Apis mellifera is the primary pollinator. We conducted this work at three sites spanning the longitudinal range of C. solstitialis in California (USA) from the coast to the Sierra Nevada Mountains. SEM revealed that bud herbivory had the largest total effect on the weed's fecundity. The direct effect of bud herbivory on final seed set was 2-4 times larger in magnitude than the direct effect of seed predation by both agents combined. SEM also revealed important indirect interactions; by reducing the number of inflorescences plants produced, bud herbivory indirectly reduced the plant's attractiveness to ovipositing seed predators. This indirect, positive pathway reduced bud herbivory's direct negative effect by 11-25%. In the same way, bud herbivory also reduced pollinator visitation, although the magnitude of this pathway was relatively small. E. villosus oviposition deterred C. succinea oviposition, which is unfortunate because C. succinea is the more voracious of the seed predators. Finally, C. succinea oviposition indirectly deterred pollinator visitation, thereby enhancing its net effect on the plant. This study demonstrates the powerful insights that can be gained from the SEM approach in understanding the multiple direct and indirect interactions among agents and pollinators and their effects on an invasive weed. Such an approach may improve our ability to manage weeds with biocontrol agents by identifying pathways that could be exploited by future agents and minimizing the possibility of interference with established agents. PMID:23387114

Swope, Sarah M; Parker, Ingrid M

2012-12-01

461

Pendimethalin phytotoxicity and seedling weed control in Indian spinach ( Basella alba L.)  

Microsoft Academic Search

Pot experiments were carried out in a screenhouse to evaluate pendimethalin effectiveness in pre-emergence weed control in Indian spinach (Basella alba L.). In the first trial, pendimethalin was applied at higher doses (0.33, 0.66, 0.99, 1.32, 1.98kgaiha?1), while in the second trial, lower doses (0.066, 0.132, 0.198, 0.264, 0.330kgaiha?1) were used. The treatments were arranged in a completely randomized design

M. A. K Smith

2004-01-01

462

[Species composition of Fusarium Link et Fr. fungal genera affecting agricultural plants and weeds in Uzbekistan].  

PubMed

Phytopathogenic fungi of the Fusarium genus are represented on the agricultural plants and weeds by 17 species and 10 subspecies from the sections Roseum, Discolor, Sporotrichiella, Elegans, Martiella, Arachniotes in Uzbekistan. As to their occurrence frequency F. javanicum, F. lateritium, F. solani, F. oxysporum, F. heterosporum, F. moniliforme, F. gibbosum species are dominating ones. F. merismoides, F. redolens, F. nivale species occurred often F. sporotichiella, F. semitectum, F. culmorum, F. bucharicum, F. graminearum, F. avenaceum species occurred rarely. It was shown that the Fusarium species were more numerous in the central and southern regions of Uzbekistan than in the northern region. PMID:11785262

Sheraliev, A Sh; Bukharov, K; Kholmuradov, Ch

463

Durum wheat and allelopathy: toward wheat breeding for natural weed management  

PubMed Central

Wheat-derived foodstuffs represent about one-fifth of the calories consumed by humans worldwide. Bread wheat (Triticum aestivum L.) is one of the most important crops throughout the world, and it has been extensively studied for its allelopathic potential. In contrast, for allelopathy in durum wheat (Triticum turgidum ssp. durum), our knowledge is partial and fragmentary. Through highlighting recent advances in using allelopathy as a crop-breeding tool, we provide an overview of allelopathy in Triticum spp., to stimulate further coordinated breeding-oriented studies, to favor allelopathy exploitation for the sustainable cultivation of wheat, and in particular, to achieve improved biological weed control.

Fragasso, Mariagiovanna; Iannucci, Anna; Papa, Roberto

2013-01-01

464

Chemical control of perennial and annual weeds in herbicide resistant soybean crops.  

PubMed

In Romania, the first tests with Roundup Ready on soybean crops were performed in 1998, on 2 soil types: a) at Teleorman Station on chernozem containing 3.5% humus, 4.5% clay b) at Br?ila Station placed in Danube Meadow on alluvial soil containing 3.90% humus and 46% clay. In every locality cultivated soybean cultivar S.2254 was resistant to glyphosate. During the three years of experiments (1998-2000) the crop of soybean was infested with various species of weeds (both annual and perennial) of which the most important are: Sorghum halepense (60-80%), Echinochloa crus-galli, Setaria glauca, Amaranthus retroflexus, Solarium nigrum, Yanthium italicum, Abutilon theoprasthi, Sinapis arvensis, Datum stramonium, Polygonum persicaria, Calystegia sepium, Cirsium arvense. In 3 years of experience the best weed control and the highest soybean production were obtained in the variants treated 2 times postemergent with Roundup Ready at a dose of 3 + 3 l/ha. Similar results were also obtained in the farms of the Academy of Agricultural Forestry Sciences, where GMO soybean was cultivated on 1500 hectares. PMID:12425098

Sarpe, N; Roibu, C; Negrila, E; Bodescu, F; Fuia, S; Popa, C; Beraru, C

2001-01-01

465

Herbicidal activity of culture filtrates of Trichoderma spp. against two problematic weeds of wheat.  

PubMed

The herbicidal potential of culture filtrates of four Trichoderma spp., namely Trichoderma harzianum Rifai, Trichoderma pseudokoningii Rifai, Trichoderma reesei Simmons and Trichoderma viride Pers., was evaluated against two problematic weeds of wheat, Phalaris minor L. and Rumex dentatus L. In laboratory bioassays, generally, metabolites of all four Trichoderma species significantly reduced various root and shoot growth parameters of the two target weed species. The original concentrations of the culture filtrates of all Trichoderma spp., except T. harzianum, significantly reduced various parameters of root and shoot growth of wheat seedlings. In a foliar spray bioassay, the culture filtrates of all four Trichoderma spp. significantly diminished root and shoot biomass of R. dentatus. The effect of these filtrates on the shoot growth of P. minor and wheat was not significant. Culture filtrates of the four Trichoderma species were successively extracted with butanol, n-hexane, chloroform and ethyl acetate. In detached leaf injection bioassays, n-hexane fractions (3 mg mL(-1)) of T. pseudokoningii, T. reesei and T. viride, and ethyl acetate fractions of T. horzianum and T. pseudokoningii were found to be toxic against R. dentatus. This study concludes that the culture filtrates of Trichoderma species have herbicidal potential in the control of R. dentatus. PMID:21462072

Javaid, Arshad; Ali, Sajjad

2011-04-01

466

Influence of type and amount of straw cover on weed emergence.  

PubMed

This research was undertaken during 2003-2004 growing season to evaluate the effects of type [forage sorghum "hybrid Cober Exp" (Sorghum bicolor x Sorghum sudanense), forage millet (Pennisetum americanum "var. BN2"), finger millet (Eleusine coracana), and St Lucia grass (Brachiaria brizantha)] and amount of straw cover (5.5 and 3.0 t ha(-1)) upon the emergence of Bidens pilosa, Chamaesyce spp., Amaranthus spp., and Commelina benghalensis, under field conditions of the Brazilian Cerrado, in the region of Uberlândia--MG. The control consisted additional treatment lacking the straw cover. Emergence of weed depended on the type and amount of straw cover, as well as the weed species. The lowest number of B. pilosa seedlings was found in the presence of forage sorghum straw; Chamaesyce spp. in the lack of straw; Amaranthus spp. in the presence of higher amount of forage sorghum and forage millet, and lower amounts of forage millet and Finger Millet. All the types and amounts of straw reduced the emergency of C. benghalensis, except at the lowest level of St Lucia grass and the lack of straw. PMID:15656176

Correia, Núbia Maria; Durigan, Julio Cezar; Klink, Urubatan Palhares

2005-01-01

467

Additions to the mycobiota of the invasive weed Miconia calvescens (Melastomataceae).  

PubMed

Miconia calvescens (Melastomataceae) is a shrub or small tree native to the Neotropics that has become one of the worst invaders of forest ecosystems, particularly in Pacific islands such as Hawaii and French Polynesia. It has been a target for biological control for more than 10 y, both with arthropod and pathogen natural enemies. Until now Colletotrichum gloeosporioides f. sp. miconiae was the only organism to be used in biological control against this weed. This fungus was introduced both in Hawaii and in French Polynesia in the late 1990s/early 2000s, where it has caused some damage to the weed, but it became evident that additional agents are needed to achieve adequate control. Exploratory surveys for plant pathogens as potential biocontrol agents of M. calvescens were undertaken in Brazil, Costa Rica and Ecuador and yielded a diverse list of pathogens, including one phytoplasma, two nematodes, one oomycete and numerous fungi. A study including the description of five fungal species found attacking M. calvescens was published recently. Herein the following additional fungi also belonging to the mycobiota of M. calvescens are described: Hyalosphaera ornata sp. nov, Microsphaeropsis miconiae sp. nov., Myrothecium miconiae sp. nov., Phyllachora miconiiphila sp. nov., as well as Hyalosphaera miconiae, Lembosia melastomatum and Microsphaeropsis clidemiae, which are recorded here for the first time on this host. Although preliminary our observations of damage to M. calvescens caused by these seven fungal species did not indicate any potential for use in classical biological control. PMID:20120231

Alves, Janaina Lana; Barreto, Robert Weingart; Pereira, Olinto Liparini; Soares, Dartanhã José

468

Phytotoxic effect, uptake, and transformation of biochanin A in selected weed species.  

PubMed

Certain isoflavones are plant growth inhibitors, and biochanin A is a major isoflavone in clover species used for weed management. The effect of biochanin A on the monocot weed species Echinochloa crus-galli L. and Lolium perenne L. and dicot species Silene noctiflora L., Geranium molle L., and Amaranthus caudatus L. was evaluated in agar medium bioassays. S. noctiflora and G. molle root growth was progressively inhibited with increasing concentrations of biochanin A, whereas the monocot species were unaffected. With regard to the dicot species, S. noctiflora (EC(50) = 35.80 ?M and EC(25) = 5.20 ?M) was more susceptible than G. molle (EC(50), EC(25) > 400 ?M). S. noctiflora, G. molle, and E. crus-galli root and shoot samples, representing a susceptible, a less susceptible, and a nonsusceptible species, respectively, were analyzed by LC-MS to quantify biochanin A and its transformation products. Biochanin A and its known transformation products genistein, dihydrobiochanin A, pratensein, and p-coumaric acid were quantified. Sissotrin was identified and quantified while assigning unknown peaks. The treated root samples contained more biochanin A, genistein, pratensein, and dihydrobiochanin A than shoot samples. PMID:23030687

Shajib, Md Tariqul Islam; Pedersen, Hans Albert; Mortensen, Anne Garfield; Kudsk, Per; Fomsgaard, Inge S

2012-10-18

469

[Characteristics of 23 species of weed in northeast of China hyperaccumulating PAHs in contaminated soils].  

PubMed

Pot experiments were conducted to investigate the 23 species of weed accumulation characteristics of phenanthrene, as a representative of polycyclic aromatic hydrocarbons (PAHs), from soil in the northeast of China. The result indicated that among the 23 species, the bioconcentration factors of Taraxacum ohwianum K., Potentilla aiscolor B. and Chelidonium majus L. were all higher than 1, which were 1.01, 4.98, 38.24 respectively. The phenanthrene concentrations in roots were 2.83, 16.34 and 9.66 mg/kg which were lower than those in aboveground part with phenanthrene concentrations were 15.18, 74.70 and 573.62 mg/kg, respectively. The hyperaccumulators were indicated by strong conveyance of phenanthrene from root to aboveground part. The analysis of phenanthrene concentration in aboveground weed and aboveground plant biomass showed that the accumulation of phenanthrene in plant were not correlated with their biomass. It concluded that Taraxacum ohwianum K., Potentilla aiscolor B. and Chelidonium majus L. had hyperaccumulative characteristics of phenanthrene, and it is possible to screen out plants with high biomass and hyperaccumulation capability. PMID:22279928

Zhang, Min; Liang, Hong; Gao, Da-Wen; Zhang, Bai-Hui; Li, Xin-Ping; Guo, Xiao-Hu

2011-10-01

470

Allelopathic Effect of Polygonum sachalinense on Plants - Using Freeze-dried Powder and Extracts for Weed Control - Allelopathic Effect of Polygonum sachalinense on Plants - Using Freeze-dried Powder and Extracts for Weed Control  

Microsoft Academic Search

Allelopathic effects of emodin and physcion existing in the rhizomes of Polygonum sachalinense on plants were examined. In petri dish assay, both emodin and physcion showed inhibition effect on germination and growth of some weeds at the concentrations of 200ppm and over, however, the inhibitory effects was not so strong. Inhibitory effects of the granules made of freeze-dried powder of

C. Asakawa; T. Maeda; M. Kurimoto; M. Akiyama; M. Amano; H. Kakuta; J. Mizutani

471

Evaluation of the Kino Coalition Weed and Seed Strategy Tucson, Arizona: 2002-2006. Statistical Analysis Center Publication.  

National Technical Information Service (NTIS)

The U.S. Department Justice (DOJ) developed Operation Weed and Seed in 1991 as a nation wide crime reduction strategy for neighborhoods with high crime rates. The strategy specifically targets violent crime and drug-related offenses and the communities in...

2006-01-01

472

DOSE RESPONSE OF WEED SEEDS AND SOIL-BORNE FUNGI PATHOGENS TO 1,3-D AND CHLOROPICRIN  

Technology Transfer Automated Retrieval System (TEKTRAN)

InLine (a combination of 1,3-dichloropropene (1,3-D) and chloropicrin) has potential to replace methyl bromide as a preplant soil fumigant. The efficacy of InLine to control five weed seeds (i.e., Polygonum arenastrum, Stellaria media, Portulaca oleracea, Malva parviflora and Erodium cicutarium) and...

473

Additive transgene expression and genetic introgression in multiple green-fluorescent protein transgenic crop × weed hybrid generations  

Microsoft Academic Search

The level of transgene expression in crop × weed hybrids and the degree to which crop-specific genes are integrated into hybrid populations are important factors in assessing the potential ecological and agricultural risks of gene flow associated with genetic engineering. The average transgene zygosity and genetic structure of transgenic hybrid populations change with the progression of generations, and the green

M. D. Halfhill; R. J. Millwood; A. K. Weissinger; S. I. Warwick; C. N. Stewart

2003-01-01

474

9 How Many and What Kind of Agents for the Biological Control of Weeds: a Case Study with Diffuse Knapweed  

Microsoft Academic Search

Overview: Following its introduction to North America, diffuse knapweed came to occupy millions of hectares of rangeland. This is the story of biological control efforts done over 25 years before an effective agent was introduced. The moral is that for optimal success of biological control, thorough work should be done to understand the ecology of the target weed and its

J. H. Myers

475

Biological control of three floating water weeds, Eichhornia crassipes, Pistia stratiotes , and Salviniamolesta in the Republic of Congo  

Microsoft Academic Search

Since 1999, four specific weevils (Coleoptera, Curculionidae) were released in the Republic of Congo against three exotic floating water weeds: Neochetina eichhorniae Warner and N. bruchi Hustache against water hyacinth, Neohydronomus affinis Hustache against water lettuce, and Cyrtobagous salviniae Calder and Sands against water fern. Recoveries of exotic weevils were made from all 24 release sites except one, and all

G. Mbati; P. Neuenschwander

2005-01-01

476

Herbivory below ground and biological weed control: life history of a root-boring weevil on purple loosestrife  

Microsoft Academic Search

The life history of the root-boring weevil Hylobius transversovittatus was studied in north and central Europe. The weevil develops on Lythrum salicaria, a perennial marshland plant that has become a problem weed in North America. It was found in all habitats of its host plant with the exception of permanently flooded sites. It also attacked L. salicaria in an early

Bernd Blossey

1993-01-01

477

Geographic range, impact, and parasitism of lepidopteran species associated with the invasive weed Lantana camara in South Africa  

Microsoft Academic Search

The current status of species of Lepidoptera associated with Lantana camara L. (lantana; Verbenaceae) in South Africa was reviewed following a survey aimed at confirming their identity, geographic range, impact on the weed, and parasitism. Six species of Lepidoptera are established on lantana of which two are native, two were probably inadvertently introduced, one was deliberately introduced, and the status

Jan-Robert Baars

2003-01-01

478

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...

479

Effect of plastic mulch on economizing irrigation water and weed control in baby corn sown by different methods  

Microsoft Academic Search

Field experiments were conducted during the winter season of 2003 -04 and 2004 -05 to determine the effect of mulch in relation to irrigation and planting method on soil temperature, weed control, baby corn growth, water use and yield. The study revealed that bed planting of baby corn caused 34.9% increase in yield over ridge planting method. Plastic mulch increased

Gulshan Mahajan; Rakesh Sharda; Ashwani Kumar; K. G. Singh

480

Microarray and growth analyses identify differences and similarities of early corn response to weeds, shade, and nitrogen stress  

Technology Transfer Automated Retrieval System (TEKTRAN)

Weed interference with crop growth is often attributed to water, nutrient, or light competition; however, specific physiological responses to these stresses are not well described. This study’s objective was to compare growth, yield, and gene expression responses of corn to nitrogen (N), low light (...

481

Fungal pathogens of Euphorbia heterophylla and E. hirta in Brazil and their potential as weed biocontrol agents.  

PubMed

A two-year survey of the fungi associated with two important congeneric pantropical weeds, Euphorbia heterophylla and E. hirta, was conducted in part of their native range in southern Brazil. Sampling was concentrated mainly in Rio de Janeiro State and ten species were identified as pathogens of these weeds. Two taxa, Botrytis ricini and Uromyces euphorbiae, were common to both weed hosts. Alternaria euphorbiicola, Bipolaris euphorbiae, Melampsora sp., Oidium sp. and Sphaceloma poinsettiae were recorded only from E. heterophylla, whereas Colletotrichum gloeosporioides, Sphaceloma sp. and Sphaerotheca fuliginea were restricted to E. hirta. Botrytis ricini and Colletotrichum gloeosporioides are new records for E. hirta, and Alternaria euphorbiicola and Sphaerotheca fuliginea are new host records for Brazil. Bipolaris euphorbiae, previously identified as Helminthosporium sp., is considered to be the correct name for the causal agent of a major disease of E. heterophyllum in Brazil. The potential of these pathogens as biocontrol agents is discussed and the mycobiota associated with both these weeds worldwide is reviewed. PMID:16284862

Barreto, R W; Evans, H C

1998-01-01

482

Chemotype variation of the weed Melaleuca quinquenervia influences the biomass and fecundity of the biological control agent Oxyops vitiosa  

Microsoft Academic Search

Host plant nutritional and non-nutritional variability can have a significant effect on herbivore populations by influencing survival, larval performance, and fecundity. The effect of chemical and physical variation of the leaves of two chemotypes of the weed Melaleuca quinquenervia was determined on the biomass and fecundity of the biological control agent Oxyops vitiosa (Coleoptera: Curculionidae). M. quinquenervia chemotypes were distinguished

G. S. Wheeler

2006-01-01

483

Improving grounded theory research in sport and exercise psychology: Further reflections as a response to Mike Weed  

Microsoft Academic Search

ObjectiveThe purposes of this paper were to respond to and expand upon Weed's (2009) critique of the use of grounded theory methodology in sport and exercise psychology. Our objectives were to clarify and correct some issues and suggest solutions to the valid problems identified.

Nicholas L. Holt; Katherine A. Tamminen

2010-01-01

484

Crop sequence, crop protection and fertility management effects on weed cover in an organic\\/conventional farm management trial  

Microsoft Academic Search

A survey of 128 plots, in 2008, of a trial where the effects of crop protection can be separated from those of fertility management, generated weed cover data within six crops (winter wheat, winter barley, spring barley, potatoes, cabbages and a grass\\/clover ley). The effects of the 2008 crop types, of the two preceding crops and of organic and conventional

M. D. Eyre; C. N. R. Critchley; C. Leifert; S. J. Wilcockson

2011-01-01

485

The initiation of a biological control programme against pompom weed Campuloclinium macrocephalum (LESS.)DC (Asteraceae)in South Africa  

Technology Transfer Automated Retrieval System (TEKTRAN)

Pompom weed, Campuloclinium macrocephalum (Less.) DC. (Asteraceae), is a South American invasive that was first recorded in South Africa in the early 1960s. In the 1980s, C. macrocephalum started slowly extending its range and in the 1990s and 2000s it entered a dramatic expansion phase. It invade...

486

Investigations into the Effects of a Certain Sea-Weed Foliar Spray (Aqua-10) on Selected Louisiana Agricultural Crops.  

National Technical Information Service (NTIS)

The purpose of this study was to conduct preliminary studies on the effects of a domestically produced Sea-weed foliar spray (Aqua-10) on several crops grown in South Louisiana. Emphasis was placed on sugar cane in this study since some 375,000 acres of c...

R. N. Falgout

1977-01-01

487

Activity, Density, and Weed Seed Predation Potential of Ground Beetles in Annual Row Crops of the Pacific Northwest  

Technology Transfer Automated Retrieval System (TEKTRAN)

Regulation of weed seed banks in agricultural systems involves management of seed input from seed rain, and seed removal from mortality and germination. While seed rain, germination, and emergence are managed using a number of methods such as tillage and herbicides, management of seed mortality is f...

488

Evaluating the effectiveness of a hydrophobic polymer for conserving water and reducing weed infection in a sandy loam soil  

Microsoft Academic Search

In this work we tested the influence of different solutions of a hydrophobic polymer named Guilspare®, applied to the soil surface to reduce soil evaporation, on the soil water status, soil temperature, crop performance and weed emergence. Two tests were carried out on a farm of the Guadalquivir river valley, southwest Spain, one with a maize crop and the other

J. E. Fernandez; J. M Murillo; M. V Cuevas; F Kohler

2001-01-01

489

Post-dispersal weed seed predation in Michigan crop fields as a function of agricultural landscape structure  

Microsoft Academic Search

Weed seed predation by invertebrates and vertebrates was compared between a simple (large crop fields embedded in a matrix of widely scattered woodlots and hedgerows) and a complex (small crop fields embedded in a matrix of numerous hedgerows and woodlots) agricultural landscape in southern Michigan. The structural differences between landscapes were evaluated by analysis of aerial photographs and digital land-use

Fabián D. Menalled; Paul C. Marino; Karen A. Renner; Douglas A. Landis

2000-01-01

490

Tank Mixing of Allelopathic Crop Water Extracts with Pendimethalin Helps in the Management of Weeds in Canola (Brassica napus) Field  

Microsoft Academic Search

A field experiment was conducted to investigate the allelopathic effects of sorghum, sunflower, brassica and rice combined with low rates of pendimethalin for weed management in canola (Brassica napus L.) field. Crop water extracts at 15 L ha -1 each in combination with pendimethalin at 400 and 600 g active ingredient (a.i.) ha-1 were sprayed immediately after sowing. Full dose

K. JABRAN; Z. A. CHEEMA; M. FAROOQ; M. HUSSAIN BASRA; H. REHMAN

491

Weed Control and Economic Comparisons of Glyphosate-Resistant, Sulfonylurea-Tolerant, and Conventional Soybean ( Glycine max ) Systems 1  

Microsoft Academic Search

A field study was conducted over 2 yr to compare efficacy and economics of glyphosate- resistant, sulfonylurea-tolerant, and conventional soybean ( Glycine max) weed control programs. Her- bicide programs in the three soybean systems provided at least 90% control of browntop millet (Brachiaria ramosa), prickly sida (Sida spinosa), yellow nutsedge (Cyperus esculentus), pitted mor- ningglory (Ipomoea lacunosa), and hemp sesbania

KRISHNA N. REDDY; KELLY WHITING

2000-01-01

492

Glyphosate resistance mechanism of Arabidopsis thaliana mutant gre1; and genetic diversity in nightshade (Solanum spp.) weed species  

Microsoft Academic Search

Glyphosate (N-phosphonomethyl glycine) the most widely used herbicide in the world, inhibits 5-enolpyruvylshikimate 3-phosphate synthase (EPSPS), the penultimate enzyme in the shikimate pathway in plants. Resistance to glyphosate has been engineered into major agronomic crops, resulting in efficient weed control. Glyphosate resistant (GR) crops are grown on 120 million ha by 12 million farmers worldwide. The widespread use of glyphosate

Altanbadralt Sharkhuu

2009-01-01

493

Comparison of SVM RBF-NN and DT for crop and weed identification based on spectral measurement over corn fields  

Technology Transfer Automated Retrieval System (TEKTRAN)

It is important to find an appropriate pattern-recognition method for in-field plant identification based on spectral measurement in order to classify the crop and weeds accurately. In this study, the method of Support Vector Machine (SVM) was evaluated and compared with two other methods, Decision ...

494

Distribution of Insect Attacks in Biological Control of Weeds: Infestation of Centaurea virgata Flowerheads by a Gall Fly  

Microsoft Academic Search

The success of biological control efforts to reduce weed density through release of insects may depend as much on the distribution of insect attacks among individual plants or plant parts as on the mean level of infestation. We used an index of dispersion to describe the distribution of Urophora quadrifasciata (Diptera: Tephritidae) galls among squarrose knapweed (Centaurea virgata) flowerheads at

Julie P. Rieder; Edward W. Evans; Susan L. Durham

2001-01-01

495

A field assessment of a potential method for weed and crop mapping on the basis of crop planting geometry  

Microsoft Academic Search

This paper describes a computer vision based technique for automatically estimating the number of crop and weed plants and the area that they cover. Images were acquired under natural lighting using a CCD video camera mounted on a small toolframe tractor equipped with a PC. This allowed mapping to be conducted in real time in the field. The mapping techniques

Nick D Tillett; T Hague; S. J Miles

2001-01-01

496

Strip-tilled Cover Cropping for Managing Nematodes, Soil Mesoarthropods, and Weeds in a Bitter Melon Agroecosystem  

PubMed Central

A field trial was conducted to examine whether strip-tilled cover cropping followed by living mulch practice could suppress root-knot nematode (Meloidogyne incognita) and enhance beneficial nematodes and other soil mesofauna, while suppressing weeds throughout two vegetable cropping seasons. Sunn hemp (SH), Crotalaria juncea, and French marigold (MG), Tagetes patula, were grown for three months, strip-tilled, and bitter melon (Momordica charantia) seedlings were transplanted into the tilled strips; the experiment was conducted twice (Season I and II). Strip-tilled cover cropping with SH prolonged M. incognita suppression in Season I but not in Season II where suppression was counteracted with enhanced crop growth. Sunn hemp also consistently enhanced bacterivorous and fungivorous nematode population densities prior to cash crop planting, prolonged enhancement of the Enrichment Index towards the end of both cash crop cycles, and increased numbers of soil mesoarthropods. Strip-tilled cover cropping of SH followed by clipping of the living mulch as surface mulch also reduced broadleaf weed populations up to 3 to 4 weeks after cash crop planting. However, SH failed to reduce soil disturbance as indicated by the Structure Index. Marigold suppressed M. incognita efficiently when planted immediately following a M. incognita-susceptible crop, but did not enhance beneficial soil mesofauna including free-living nematodes and soil mesoarthropods. Strip-tilled cover cropping of MG reduced broadleaf weed populations prior to cash crop planting in Season II, but this weed suppression did not last beyond the initial cash crop cycle.

Wang, Koon-Hui; Sipes, Brent S.; Hooks, Cerruti R.R.

2010-01-01

497

Potential improvement in rice seedling establishment and weed suppression in reduced-input systems using osmotically pre-conditioned seed  

Technology Transfer Automated Retrieval System (TEKTRAN)

Asian indica rice cultivars have exhibited suppression potential against barnyardgrass (Echinochloa crus-galli) in drill-seeded, flood-irrigated production systems in the U.S. However, the degree of weed suppression has been inconsistent, and is dependent on environmental and production factors whi...

498

ENHANCED DEGRADATION OF ATRAZINE UNDER FIELD CONDITIONS CORRELATES WITH A LOSS OF WEED CONTROL IN THE GLASSHOUSE  

Technology Transfer Automated Retrieval System (TEKTRAN)

Enhanced degradation of atrazine has been reported in the literature indicating the potential for reduced residual weed control with this herbicide. Experiments were conducted to determine the field dissipation of atrazine in three cropping systems: continuous Zea mays L. (CC) receiving atrazine a...

499

Environmental Impact of the South Carolina Public Service Authority's FY'76 Aquatic Weed Control Program in Lake Marion.  

National Technical Information Service (NTIS)

The study area consists of 750 acres of weed-choked waters in the Rimini Trestle area near the northern end of Lake Marion, in Sumter County, South Carolina. Thirty tons of granualr 2,4-D was applied on August 4-6, 1975, to eradicate Water Primrose. Then ...

J. R. Inabinet

1979-01-01

500

Interplanting ryegrass in winter leek: effect on weed control, crop yield and allocation of N-fertiliser  

Microsoft Academic Search

The potential effect of two sowing dates of ryegrass, Lolium perenne L. var. Elka as an interplant in winter leek, Allium porrum L., on weed control, soil nitrogen allocation and crop yield was studied at two sites in Switzerland. In order to reduce potential competition with the ryegrass, row application of the herbicide methazol (as additional treatment) and increased fertiliser

Heinz Mijller-SchZrer