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1

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.

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

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...

4

Weed ManagementWeed ManagementWeed ManagementWeed ManagementWeed Management Purdue Extension  

E-print Network

alfalfa stands may need additional weed management. The most common weed control practices for alfalfa are with mechanical and chemical means. Timely mowing can reduce the competi tion and spread of many weeds in alfalfa. Proper application timing will improve weed control, prevent conflicts with harvest restrictions

Holland, Jeffrey

5

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

6

Non-parasitic weeds  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

7

Modelling weed emergence patterns  

Microsoft Academic Search

Anticipating weed pressure may be important in selecting and timing weed control measures in order to optimize their effectiveness, and thus reduce herbicide use. Therefore, a predictive model of the time of emergence and the numbers of seedling emerging (the weed emergence pattern) after soil cultivation may be a useful tool in integrated weed management. In this study, a simulation

L. M. Vleeshouwers

1997-01-01

8

DEVELOPING WEED MANAGEMENT STRATEGIES THAT ADDRESS WEED SPECIES SHIFTS AND HERBICIDE RESISTANT WEEDS  

E-print Network

DEVELOPING WEED MANAGEMENT STRATEGIES THAT ADDRESS WEED SPECIES SHIFTS AND HERBICIDE RESISTANT Minnesota's major corn and soybean weed management problems. Herbicide Resistant Weeds: Weeds herbicide programs. Weeds with a diverse genetic background may have a resistant biotype that has a 1 in 1

Minnesota, University of

9

Eradication of Major Weeds  

ERIC Educational Resources Information Center

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

Indian Journal of Adult Education, 1975

1975-01-01

10

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...

11

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.

12

Invasive Weed Outreach in Earl Creech  

E-print Network

infestations Extension Program #4 Integrated Weed Management Use multiple methods to control weeds Mechanical at Purdue What does the Extension Weed Specialist do? Control Nevada's weeds What does the Extension Weed Specialist do? Control Nevada's weeds Enforce weed control laws What does the Extension Weed Specialist do

Nowak, Robert S.

13

Bioherbicides for Weed Control  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

14

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...

15

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...

16

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...

17

WeedControl WEED CONTROL IN FLUE-CUREDTOBACCO  

E-print Network

37 WeedControl WEED CONTROL IN FLUE-CUREDTOBACCO Charles S. Johnson, Extension Plant Pathologist - sands, loamy sands, and sandy loams; Medium Soils - sandy clay loams, loams, silt loams, and silts; Fine germination. Already established weeds are not significantly affected. All weed growth and crop stubble should

Liskiewicz, Maciej

18

Weeds on the Web  

NSDL National Science Digital Library

The Wildland Invasive Species Program of The Nature Conservancy (TNC) hosts this interesting and light-hearted page on the invasive plants currently threatening the biodiversity of wild lands in the US. Appropriate for undergraduates, educators will find much here on weeds (what they are, which ones are worst), weed control methods, and suggestions for including action in lesson plans. For starters, click on any state in the US map to find out about the worst invasive plants in that state. Those seeking detailed information should consult the Element Stewardship Abstracts, which describe over 100 species in terms of Scientific and Common Name, Description of Characteristics, Biology/ Ecology, Global Range, Stewardship Profile, Threats Posed by this Species, Biological Control, Research Needs, and more. Also at the site are lists of effective weed tools, weeds in the news, and links to weed-related events.

19

SUGGESTIONS FOR WEED CONTROL IN  

E-print Network

and mechanical weed control include: 1. Remove light or spotty infestations of weeds by hand hoeing or spot for continued infestation. 5. Consider the economics of using mechanical cultivation alone for weed controlB-5038 10-98 SUGGESTIONS FOR WEED CONTROL IN PASTURES AND FORAGES Texas Agricultural Extension

Mukhtar, Saqib

20

EMERGING WEED PROBLEMS IN MINT  

Technology Transfer Automated Retrieval System (TEKTRAN)

New weed problems continue to evolve in mint production. Common groundsel, western salsify, white cockle, rattail fescue are four weeds that are difficult to control and often escape weed management programs in mint production. All four of these weeds have the ability to germinate in fall and spr...

21

Weed Biotypes Weed Management in Grain  

E-print Network

options, but for grain sorghum the key is atrazine: 0.25-1.0 lbs. atrazine per acre to strengthen and expand weed control (from the label) This atrazine appears somewhat lower than for straight atrazine control with Huskie + atrazine. A B Credit: Dr. Pete Dotray #12;Huskie Herbicide for GS (2012

Behmer, Spencer T.

22

Modelling weed emergence patterns in arable weeds  

Microsoft Academic Search

A model was developed to simulate weed emergence patterns after soil cultivation. In the model, the consecutive processes of dormancy release, germination and pre-emergence growth were modelled in separate modules. Input variables of the model were: date of soil cultivation, soil temperature and soil penetration resistance. Output variables of the model were: seedling density and timing of seedling emergence. The

L. M. Vleeshouwers; M. J. Kropff

2000-01-01

23

Weeds of the South  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

24

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

25

Weeds and Fire  

NSDL National Science Digital Library

Students will locate some weed and native species found in Oregon and will understand that while databases are beneficial in studying plant populations, local on-the-ground information is commonly more up-to-date and that both are required to make large scale management decisions. Students will learn that the invasion of weeds commonly follows on the heels of a disturbance (natural or otherwise) and be introduced to some of the factors that impact the success of weeds in a particular ecosystem. Students will begin to relate the data to real-life situations and how they could be used to create management plans/strategies and/or alter existing management practices. This resource includes both a teaching guide and student worksheets.

Kenna, Sean

26

INTRODUCTION Weed invasion hypotheses  

E-print Network

) in invaded areas of Europe and in its native area of the Caucasus STEEN OLE HANSEN1 , JAN HATTENDORF1 the Caucasus into Western Europe more than 150 years ago and later became an invasive weed which created major hogweed (Caucasus) and were compared to those found on plants in

Richner, Heinz

27

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...

28

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.

29

A Weed Cantilever  

ERIC Educational Resources Information Center

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

Keller, Elhannan L.; Padalino, John

1977-01-01

30

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.

31

INTEGRATED WEED MANAGEMENT FOR ORGANIC FIELD CROPS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Organic farmers identify weeds as their primary production problem. Successful management of weeds in organic production systems depends on applying integrated weed management principles. The central guidelines for applying integrated weed management in organic field crops are: 1) target all weed l...

32

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.

33

7 CFR 201.15 - Weed seeds.  

Code of Federal Regulations, 2010 CFR

... 3 2010-01-01 2010-01-01 false Weed seeds. 201.15 Section 201.15 Agriculture...REGULATIONS Labeling Agricultural Seeds § 201.15 Weed seeds. The percentage of weed seeds shall include seeds of plants...

2010-01-01

34

7 CFR 201.15 - Weed seeds.  

Code of Federal Regulations, 2012 CFR

... 3 2012-01-01 2012-01-01 false Weed seeds. 201.15 Section 201.15 Agriculture...REGULATIONS Labeling Agricultural Seeds § 201.15 Weed seeds. The percentage of weed seeds shall include seeds of plants...

2012-01-01

35

7 CFR 201.15 - Weed seeds.  

Code of Federal Regulations, 2014 CFR

... 3 2014-01-01 2014-01-01 false Weed seeds. 201.15 Section 201.15 Agriculture...REGULATIONS Labeling Agricultural Seeds § 201.15 Weed seeds. The percentage of weed seeds shall include seeds of plants...

2014-01-01

36

7 CFR 201.15 - Weed seeds.  

Code of Federal Regulations, 2013 CFR

... 3 2013-01-01 2013-01-01 false Weed seeds. 201.15 Section 201.15 Agriculture...REGULATIONS Labeling Agricultural Seeds § 201.15 Weed seeds. The percentage of weed seeds shall include seeds of plants...

2013-01-01

37

7 CFR 201.15 - Weed seeds.  

Code of Federal Regulations, 2011 CFR

... 3 2011-01-01 2011-01-01 false Weed seeds. 201.15 Section 201.15 Agriculture...REGULATIONS Labeling Agricultural Seeds § 201.15 Weed seeds. The percentage of weed seeds shall include seeds of plants...

2011-01-01

38

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

39

Weed flora and weed management of field peas in Finland  

Microsoft Academic Search

The composition of the weed flora of dry pea (Pisum sativum L.) fields and cropping practices were inves- tigated in southwestern Finland. Surveys were done in 2002-2003 in 119 conventionally cropped fields and 64 fields under organic cropping. Herbicides were applied to 92% of conventionally cropped fields where they provided relatively good control but were costly. Weeds were controlled mechanically

Jukka Salonen; Terho Hyvönen; Heikki Jalli

2005-01-01

40

Assistant Professor Agronomy (Weed Science)  

E-print Network

Ramon Leon Assistant Professor Agronomy (Weed Science) Research Focus Dr. Leon has a 60% research and 40% extension appointment in the Agronomy Department at the University of Florida. The goal of his · B.S. University of Costa Rica Agronomy. 2000 Employment · Assistant Professor, Weed Science, West

Watson, Craig A.

41

Weed Identification Field Training Demonstrations.  

ERIC Educational Resources Information Center

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

Murdock, Edward C.; And Others

1986-01-01

42

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...

43

296 Weed Science 53, MayJune 2005 Weed Science, 53:296306. 2005  

E-print Network

, mechanical weed control, wheat underseeded with red clover), and organic (ORG; same as RI but no synthetic296 · Weed Science 53, May­June 2005 Weed Science, 53:296­306. 2005 Weed seedbank and community of Agriculture­Agricultural Research Services, Invasive Weeds Management Unit, N-319 Turner Hall, 1102 South

Sims, Gerald K.

44

94 Weed Science 54, JanuaryFebruary 2006 Weed Science, 54:9499. 2006  

E-print Network

with metham, the stale seedbed technique, mechanical cul- tivation, and hand weeding (Anonymous 2002). High. Therefore, hand weed- ing is an important tactic employed after crop emergence to control weeds escaping all94 · Weed Science 54, January­February 2006 Weed Science, 54:94­99. 2006 Volunteer potato

Sims, Gerald K.

45

Weed to Wonder  

NSDL National Science Digital Library

Human ingenuity never ceases! This wonderful website from the Cold Spring Harbor Laboratory tells the story of how a common Mexican weed (teosinte) was slowly manipulated by humans until it transformed into corn. As an introduction, users might want to start by watching a 2 minute and 50 second video of maize plants growing at Cold Spring Harbor Laboratory. After that, it's a good idea to look over the six separate sections here, which include Domestication, Hybrid Vigor, Genome Sequencing, and Jumping Genes. Each area contains explanatory text, photos, primary documents, and thoughtful explanations of complex scientific ideas.

2012-01-01

46

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...

47

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.

48

7 CFR 201.50 - Weed seed.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Weed seed. 201.50 Section 201.50 ...Administration of the Act § 201.50 Weed seed. Seeds (including bulblets or tubers) of plants shall be considered weed seeds when recognized as weed...

2010-01-01

49

Weeding the School Library Media Collection.  

ERIC Educational Resources Information Center

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

School Library Media Quarterly, 1984

1984-01-01

50

7 CFR 201.50 - Weed seed.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 2012-01-01 false Weed seed. 201.50 Section 201.50 ...Administration of the Act § 201.50 Weed seed. Seeds (including bulblets or tubers) of plants shall be considered weed seeds when recognized as weed...

2012-01-01

51

7 CFR 201.50 - Weed seed.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Weed seed. 201.50 Section 201.50 ...Administration of the Act § 201.50 Weed seed. Seeds (including bulblets or tubers) of plants shall be considered weed seeds when recognized as weed...

2013-01-01

52

7 CFR 201.50 - Weed seed.  

Code of Federal Regulations, 2014 CFR

...2014-01-01 2014-01-01 false Weed seed. 201.50 Section 201.50 ...Administration of the Act § 201.50 Weed seed. Seeds (including bulblets or tubers) of plants shall be considered weed seeds when recognized as weed...

2014-01-01

53

7 CFR 201.50 - Weed seed.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 2011-01-01 false Weed seed. 201.50 Section 201.50 ...Administration of the Act § 201.50 Weed seed. Seeds (including bulblets or tubers) of plants shall be considered weed seeds when recognized as weed...

2011-01-01

54

Seasonal Weed Control for Northeast Florida  

E-print Network

1 Seasonal Weed Control for Northeast Florida #12;2 Introduction Weed control is a constant battle activities and can help you to spot a problem weed before it takes over the entire pasture. Control options will be determined by the type of weed, size of plant and budget. Mechanical treatments like mowing are an effective

Jawitz, James W.

55

Microbial weed control and microbial herbicides  

Technology Transfer Automated Retrieval System (TEKTRAN)

Microbes can be used in weed control. There have been many investigations of potential products for weed management. Some have been successful at suppressing weeds in the field and a select few are marketed products that now reduce weed infestations. Further studies are needed to continue to searc...

56

Can Global Weed Assemblages Be Used to Predict Future Weeds?  

PubMed Central

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

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

2013-01-01

57

Can global weed assemblages be used to predict future weeds?  

PubMed

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

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

2013-01-01

58

Using Stochastic Effciency Analysis To Factor Distribution Of Weed Escapes Into Weed Management Decisions  

Technology Transfer Automated Retrieval System (TEKTRAN)

Weeds in patches may be more easily managed than the same number of weeds spread throughout the field. We explored choosing weed management strategies based on both net return and the distribution of weed escapes within a field. Expected net returns with several different postemergence herbicides of...

59

Patchy weed distribution and site-specific weed control in winter cereals  

Microsoft Academic Search

Site-specific weed control in winter cereals was performed on the same fields every year over a 5-year period (1999–2003). The most common weeds (Apera spica-venti, Galium aparine, Veronica hederifolia, Viola arvensis) were counted by species, at grid points which were georeferenced and the data were analysed spatially. For weed control, weeds were grouped into three classes: grass, broad-leaved weeds (without

Henning Nordmeyer

2006-01-01

60

Weed Research Texas AgriLife Research  

E-print Network

107L-08 KIXOR - GRAIN SORGHUM - BURNDOWN 22 108L-08 KIXOR - GRAIN SORGHUM - WEED CONTROL - I 27 109L-08 KIXOR - GRAIN SORGHUM - WEED CONTROL - II 30 110L-08 KIXOR - COTTON - BURNDOWN 33 111L-08 COTTON SORGHUM - TOLERANCE - II 76 121L-08 WEED CONTROL PROG. WITH EXPRESS HERBICIDE IN EXPRESSSUN TRAIT PIONEER

Mukhtar, Saqib

61

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

62

Control of Summer Annual Grass Weeds  

E-print Network

Control of Summer Annual Grass Weeds in Turfgrasses Summer annual grasses continue to be pervasive weed problems in many turfgrass areas throughout Pennsylva nia. The most common summer annual grasses.), and barnyard grass (Echi- nochloa crusgalli). Satisfactory control of these weeds can be obtained by cultural

Kaye, Jason P.

63

Weed control efficacy with Racer (ammonium nonanoate)  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

64

Using weeds to fight wastes  

SciTech Connect

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

NONE

1992-10-01

65

PLNTSOIL 310 WEED SCIENCE HERBARIUM  

E-print Network

collected specimen of a flowering plant, a herbarium specimen, consists of two equally important parts1 PLNTSOIL 310 WEED SCIENCE HERBARIUM Plant, Soil and Insect Sciences, University of Massachusetts: a sample of the plant itself, and the label data to go with it. The Specimen The specimen should include

Schweik, Charles M.

66

WEED CONTROL RESEARCH IN MINT  

Technology Transfer Automated Retrieval System (TEKTRAN)

In greenhouse trials, Western salsify, a difficult to control weed in mint, was controlled with preemergence applied flumioxazin, sulfentrazone, terbacil and oxyfluorfen. In field trials, sulfentrazone and flumioxazin applied preemergence in fall or spring were safe on native spearmint and peppermi...

67

RHIZOBACTERIA INHIBITORY TO GRASS WEEDS.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Soil bacteria have been discovered that can be used as biological agents to suppress downy brome and certain other grass weeds in small grains. Our research on these organisms has shown that their use has the potential to reduce tillage, agrochemical usage and related ground and surface water conta...

68

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...

69

WEED CONTROL BPG NOTE 11 Best Practice Guidance  

E-print Network

. Weed control methods Cultural With any weed control strategy, basic cultural/mechanical good practiceWEED CONTROL BPG NOTE 11 Best Practice Guidance for Land Regeneration Introduction Weed control and early growth of newly planted trees. Failure to control weeds represents one of the single most

70

The future for weed control and technology.  

PubMed

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

Shaner, Dale L; Beckie, Hugh J

2014-09-01

71

Mechanical Destruction of Weeds: A Review  

Microsoft Academic Search

Methods of mechanical destruction of weeds in relation to their biology are reviewed. Depending on the stage of growth and\\u000a type of weed, i.e. the depth at which new shoots can be formed and the ability to withstand burial, implements inflict damage\\u000a on weeds in different ways: cutting, burial, uprooting. The various types of damage are shown. The three main

D. Chicouene

72

Mechanical destruction of weeds. A review  

Microsoft Academic Search

The various methods of mechanical removal of weeds in relation to their biology are reviewed. Depending on the stage of growth\\u000a and type of weed, i.e. the depth at which new shoots can be formed and the ability to withstand burial, implements inflict\\u000a damage on weeds in different ways: cutting, burial or uprooting. The various types of damage are exemplified.

D. Chicouene

2007-01-01

73

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

74

N-Q Weed killer  

NSDL National Science Digital Library

This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: A liquid weed-killer comes in four different bottles, all with the same active ingredient. The accompanying table gives information about the concentra...

75

Nutrient absorbtion of weeds in maize.  

PubMed

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

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

2008-01-01

76

Dominant species of dicot-weeds and weed biodiversity in spring barley in Latvia.  

PubMed

The composition of weed species in spring barley and weed biodiversity was evaluated in experiments in different growing seasons and with different previous crops. The aim of the experiments was to evaluate the composition of weed species in spring barley during a four year period in weather conditions of different growing seasons and with different previous crop as well as to assess the biodiversity in the experiments where the different groups of herbicides were applied. Over years and previous crops, the dicotyledonous weed community was dominated by Chenopodium album, followed by Viola arvensis. The herbicides from different groups had significant influences on the biodiversity of weeds. PMID:21542476

Vanaga, I; Mintale, Z; Smirnova, O

2010-01-01

77

Alternative weed management practices: Effects on weed control, grapevine performance, and soil quality in an established midwestern vineyard.  

E-print Network

??Sustainable grape production entails the implementation of management practices that control weeds, maintain grapevine performance, and conserve soil quality. Conventional weed management practices include herbicide… (more)

Wasko, Lisa Marie

2010-01-01

78

WEED SUPPRESSION WITH ORGANIC MULCH IN ORCHARDS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Synthetic herbicides often are used to control weeds that cause yield loss and contribute to insect pests and diseases in orchards. Alternative weed management may be required due to negative public perception and possible regulatory restriction of some synthetic herbicides and to the increase of o...

79

PRECISION FARMING TECHNIQUES FOR WEED MANAGEMENT  

Technology Transfer Automated Retrieval System (TEKTRAN)

Preliminary studies were conducted to investigate methods of geo- referencing weed locations in fields for site-specific application of herbicides. Ground-based and aerial methods were examined. Ground-based methods included scouting fields with a backpack GPS and marking areas where weeds were pr...

80

Nutsedge ecology in plasticulture affects weed management  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

81

Why herbicides fail Extension Weed Specialist  

E-print Network

Why herbicides fail J. Ferrell Extension Weed Specialist and Greg MacDonald Weed Scientist #12;Where we are today · Herbicides are more potent and environmentally friendly than ever before ­ Much lower use rates (ounces vs. pounds/A) ­ Greater selectivity #12;#12;#12;Why do herbicides fail

Watson, Craig A.

82

Software Tools for Weed Seed Germination Modeling  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

83

Scythe (pelargonic acid) weed control in squash  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

84

Weed competition and dry bean yield components  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

85

Biological Significance of Low Weed Population Densities on Sweet Corn  

Technology Transfer Automated Retrieval System (TEKTRAN)

Some weed plants escape current weed management systems in nearly all sweet corn (Zea mays L.) fields. Decisions to target escaped weeds, and justify the added expense, require knowledge of the biological significance of low weed population densities on the crop. The objectives were to 1) quantify g...

86

Identifying soybean traits of interest for weed competition  

Technology Transfer Automated Retrieval System (TEKTRAN)

Organic soybean producers rely on a variety of tactics for weed management. The use of soybean cultivars with enhanced ability to compete with weeds may increase weed control. Our objective was to identify genetic traits that may enhance soybean’s competitive ability to suppress weeds. Experimental ...

87

A survey of weeds and herbicides in Georgia Pecan  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

88

A Survey of Weeds in Various Crops in Georgia 1  

Microsoft Academic Search

A survey of county extension agents was conducted in 1998 to determine the most troublesome weeds in corn, cotton, forages and pastures, peanut, small grains, soybean, tobacco, and vegetables in Georgia. The most troublesome weed statewide averaged over all crops was sicklepod. It was the most troublesome weed in cotton and soybean and among the four most troublesome weeds in

THEODORE M. WEBSTER; GREGORY E. MACDONALD

2001-01-01

89

Weed species shifts in glyphosate-resistant crops.  

PubMed

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

Owen, Micheal D K

2008-04-01

90

Weed seeds on clothing: a global review.  

PubMed

Weeds are a major threat to biodiversity including in areas of high conservation value. Unfortunately, people may be unintentionally introducing and dispersing weed seeds on their clothing when they visit these areas. To inform the management of these areas, we conducted a systematic quantitative literature review to determine the diversity and characteristics of species with seeds that can attach and be dispersed from clothing. Across 21 studies identified from systematic literature searches on this topic, seeds from 449 species have been recorded on clothing, more than double the diversity found in a previous review. Nearly all of them, 391 species, are listed weeds in one or more countries, with 58 classified as internationally-recognised environmental weeds. When our database was compared with weed lists from different countries and continents we found that clothing can carry the seeds of important regional weeds. A total of 287 of the species are listed as aliens in one or more countries in Europe, 156 are invasive species/noxious weeds in North America, 211 are naturalized alien plants in Australia, 97 are alien species in India, 33 are invasive species in China and 5 are declared weeds/invaders in South Africa. Seeds on the clothing of hikers can be carried to an average distance of 13 km, and where people travel in cars, trains, planes and boats, the seeds on their clothing can be carried much further. Factors that affect this type of seed dispersal include the type of clothing, the type of material the clothing is made from, the number and location of the seeds on plants, and seed traits such as adhesive and attachment structures. With increasing use of protected areas by tourists, including in remote regions, popular protected areas may be at great risk of biological invasions by weeds with seeds carried on clothing. PMID:24956465

Ansong, Michael; Pickering, Catherine

2014-11-01

91

WEED MANAGEMENT IN POTATOES WITH SPARTAN HERBICIDE  

Technology Transfer Automated Retrieval System (TEKTRAN)

Spartan (sulfentrazone) is a new herbicide for weed management in potatoes. Sulfentrazone applied preemergence controls hairy and black nightshade, redroot pigweed, common lambsquarters, and kochia in potatoes. Spartan may be tank mixed with metribuzin, s-metolachlor, rimsulfuron, pendimethalin, o...

92

Kyllinga, troublesome sedge weeds in turf  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

93

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

94

Global perspective of herbicide-resistant weeds.  

PubMed

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

Heap, Ian

2014-09-01

95

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

96

248 Weed Science 50, MarchApril 2002 Weed Science, 50:248260. 2002  

E-print Network

248 · Weed Science 50, March­April 2002 Weed Science, 50:248­260. 2002 Applications of hydrothermal et al. 2000). This ability of seeds to remain viable but quiescent allows them to persist in soil them to persist as soil seed banks from which a fraction of seeds are available to germinate

Bradford, Kent

97

264 Weed Science 53, MarchApril 2005 Weed Science, 53:264273. 2005  

E-print Network

in developing decision support systems (DSSs) that use remote sensing information, practical examples of how of remote sensing data into weed management decisions David R. Shaw Corresponding author. Plant & Soil@gri.msstate.edu Remote sensing and associated spatial technologies provide tremendous opportunity to enhance weed

Brown, Cynthia S.

98

236 Weed Science 53, MarchApril 2005 Weed Science, 53:236241. 2005  

E-print Network

236 · Weed Science 53, March­April 2005 Weed Science, 53:236­241. 2005 Symposium Predicting, Montana State University, Bozeman, MT 59717 To manage or control nonindigenous species (NIS), we need, dalmation toadflax, and timothy were chosen for this study because of their different dispersal mechanisms

Brown, Cynthia S.

99

7 CFR 201.52 - Noxious-weed seeds.  

Code of Federal Regulations, 2013 CFR

...for the classification of weed seeds and inert matter, respectively. (b) A noxious-weed seed examination of coated seed samples shall be made by examining...FR 64499, Dec. 14, 1994] germination tests in the administration...

2013-01-01

100

7 CFR 201.52 - Noxious-weed seeds.  

Code of Federal Regulations, 2012 CFR

...for the classification of weed seeds and inert matter, respectively. (b) A noxious-weed seed examination of coated seed samples shall be made by examining...FR 64499, Dec. 14, 1994] germination tests in the administration...

2012-01-01

101

7 CFR 201.52 - Noxious-weed seeds.  

Code of Federal Regulations, 2011 CFR

...for the classification of weed seeds and inert matter, respectively. (b) A noxious-weed seed examination of coated seed samples shall be made by examining...FR 64499, Dec. 14, 1994] germination tests in the administration...

2011-01-01

102

7 CFR 201.52 - Noxious-weed seeds.  

Code of Federal Regulations, 2014 CFR

...for the classification of weed seeds and inert matter, respectively. (b) A noxious-weed seed examination of coated seed samples shall be made by examining...FR 64499, Dec. 14, 1994] germination tests in the administration...

2014-01-01

103

Sequential applications of pelargonic acid for weed control in squash  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

104

LESS KNOWN USES OF WEEDS AS MEDICINAL PLANTS  

PubMed Central

In this paper the author presents medicinal or otherwise useful weed species with details of family, vernacular name and its medicinal utility. Information on other general economic importance of medicinal weeds is also described here. PMID:22557414

Sahu, T. R.

1984-01-01

105

STRATEGIES FOR DEVELOPING BIOHERBICIDES FOR SUSTAINABLE WEED MANAGEMENT  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

106

An ultrasonic system for weed detection in cereal crops.  

PubMed

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. PMID:23443401

Andújar, Dionisio; Weis, Martin; Gerhards, Roland

2012-01-01

107

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

108

Agricultural weed research: a critique and two proposals  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

109

Alternative weed control-an update on USDA research  

Technology Transfer Automated Retrieval System (TEKTRAN)

Weed control research at the USDA, ARS, South Central Agricultural Research Laboratory at Lane, OK investigates a wide range of management practices for weed control in vegetable crops. Alternative weed control materials investigated during the 2004 growing season included corn gluten meal (CGM), v...

110

Simple tools and software for precision weed mapping  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

111

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

112

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

113

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

114

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

115

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

116

7 CFR 201.52 - Noxious-weed seeds.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Noxious-weed seeds. 201.52 Section 201.52...Administration of the Act § 201.52 Noxious-weed seeds. (a) The determination of...bulblets, or tubers of individual noxious weeds present per unit weight should be...

2010-01-01

117

HORTICULTURAL & FOREST CROPS 2014 Nursery Crops: Weeds 4-41  

E-print Network

an herbicide. Chemical Weed Control There is now a selection of herbicides for use in nursery stock. Selection of a given herbicide must be based on the particular weed and crop situation. None of the preemergent herbicides are effective against all weed species. Tank-mixing of herbicides often broadens the spectrum

Liskiewicz, Maciej

118

Integrating Residual Herbicides into Corn and Soybean Weed Management  

E-print Network

% 1. Use mechanical control 2. Rotate herbicide mode of action 3. Not concerned about weed resistance but lambsquarters In the 1990's MN farmers readily adopted Postemergence weed control because it decoupled planting-resistance in all but lambsquarters In the 1990's MN farmers readily adopted Postemergence weed control because

Minnesota, University of

119

WEED SEEDLING EMERGENCE MODELLING: CONVERTING OBSERVATIONS INTO EQUATIONS FOR WEEDEM  

Technology Transfer Automated Retrieval System (TEKTRAN)

The timing and extent of weed seedling emergence are critical variables for successful weed management in arable crops. Although observations of the timing and extent of weed seedling emergence have been reported often, our abilities to predict these variables have not progressed as rapidly as neede...

120

Seeds as the Target for Biological Control of Weeds  

Microsoft Academic Search

Seeds play an essential role in the maintenance and spread of annual weeds, yet they are vulnerable to pre- and post-dispersal predators, some of which might affect the dynamics of weed populations. We conducted studies to identify pre- and post-dispersal predators of the annual broadleaf weeds giant ragweed (Ambrosia trifida) and velvetleaf (Abutilon theophrasti), and to determine levels of seed

J. Cardina; S. K. Harrison; E. E. Regnier; J. T. Schmoll

121

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

122

The biology of Canadian weeds. 134. Bromus inermis Leyss  

E-print Network

The biology of Canadian weeds. 134. Bromus inermis Leyss R. Otfinowski1, N. C. Kenkel1, and P. M. The biology of Canadian weeds. 134. Bromus inermis Leyss. Can. J. Plant Sci. 87: 183­198. Smooth brome (Bromus and cover crop in every province and territory in Canada. Key words: Bromus inermis, weed biology, prairie

Kenkel, Norm

123

Effect of Fertilizer Nitrogen on Weed Emergence and Growth  

Microsoft Academic Search

The timing of nitrogen (N) fertilizer application may influence germination, emergence, and competitiveness of weeds. Research was conducted to determine the influence of total inorganic soil N( N it) on the germination, emergence, and growth of five weed species. In a greenhouse experiment, seed of five weed species were exposed to four levels of N, and seed germination was measured.

Amy E. Sweeney; Karen A. Renner; Carrie Laboski; Adam Davis

2008-01-01

124

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...

125

The Effect of Laser Treatment as a Weed Control Method  

Microsoft Academic Search

A laser beam directed towards weeds can be an efficient weed control method as an alternative to herbicides. Lasers may deliver high-density energy to selected plant material, raising the temperature of the water in the plant cells and thereby stop or delay the growth. A commercial use of lasers for weed control, however, require a systematic investigation of the relationship

Solvejg K. Mathiassen; Thomas Bak; Svend Christensen; Per Kudsk

2006-01-01

126

237-Response of a weed community to nitrogen fertilization -Response of a weed community to nitrogen fertilization  

E-print Network

237- Response of a weed community to nitrogen fertilization - Response of a weed community to nitrogen fertilization: a multivariate analysis Pysek, Petr1 & Leps, Jan2 1Institute of Applied Ecology, CS-mail KRIVAN%CSEARN@SEARN; Abstract. The effect of nitrogen fertilizers on the composition of a weed community

Leps, Jan "Suspa"

127

Effects of repeated clover undersowing, green manure ley and weed harrowing on weeds and yields in organic cereals  

Microsoft Academic Search

Cover crops can be used to reduce leaching and erosion, introduce variability into crop rotation and fix nitrogen (N) for use by the main crops, less is however known about effects on weeds. The effects on weed seed bank, weed growth and grain yield of 4 years of annual undersown clover and ryegrass alone and in combination, and one of

Helge Sjursen; Lars Olav Brandsćter; Jan Netland

2012-01-01

128

Effects of repeated clover undersowing, green manure ley and weed harrowing on weeds and yields in organic cereals  

Microsoft Academic Search

Cover crops can be used to reduce leaching and erosion, introduce variability into crop rotation and fix nitrogen (N) for use by the main crops, less is however known about effects on weeds. The effects on weed seed bank, weed growth and grain yield of 4 years of annual undersown clover and ryegrass alone and in combination, and one of

Helge Sjursen; Lars Olav Brandsćter; Jan Netland

2011-01-01

129

Detecting Weed Infestations in Soybean Using Remote Sensing.  

NASA Astrophysics Data System (ADS)

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

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

2007-12-01

130

Weed Busters: How to Pound Threadleaf Groundsel  

E-print Network

L-5470 9/05 How to Pound Threadleaf Groundsel (Senecio) Safe and effective three-step ways to control threadleaf groundsel Weed Treatment Series Allan McGinty, Charles Hart and J. F. Cadenhead Extension Range Specialists The Texas A&M University..., in cooperation with the United States Department of Agriculture. Edward G. Smith, Director, Texas Cooperative Extension, The Texas A&M University System. 1.5M, New T readleaf groundsel, also known as Senecio, is a shrubby perennial weed commonly found...

McGinty, Allan; Hart, Charles R.; Cadenhead, J. F.

2005-10-05

131

Detecting Late-Season Weed Infestations in Soybean (Glycine max) 1  

Microsoft Academic Search

Field experiments were conducted in 1999 at Stoneville, MS, to determine the potential of multispectral imagery for late-season discrimination of weed-infested and weed-free soybean. Plant canopy composition for soybean and weeds was estimated after soybean or weed canopy closure. Weed canopy estimates ranged from 30 to 36% for all weed-infested soybean plots, and weeds present were browntop millet, barnyardgrass, and

CLIFFORD H. KOGER; DAVID R. SHAW; CLARENCE E. WATSON; KRISHNA N. REDDY

2003-01-01

132

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. PMID:23872717

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

2013-01-01

133

RISING CARBON DIOXIDE AND WEED ECOLOGY  

Technology Transfer Automated Retrieval System (TEKTRAN)

Documented and projected changes in the concentration of atmospheric carbon dioxide [CO2] and other gases suggest potential changes in climate stability which could negatively impact human systems. One such system would involve negative impacts on agricultural crops and associated weeds. Climatic o...

134

Diversifying spring wheat systems influences weed community  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

135

Acetic acid and weed control in onions  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

136

Extension/Research Professor of Weed Science  

E-print Network

, July 1927 · "Sulfuric, hydrochloric and nitric acids are positively destructive to the plant feet would seem a fair estimate." #12;Sulfuric Acid Spray: A practical means for the control of weeds countries for number of years 2 to 15% solution of sulfuric acid used, depending on species and size, which

Watson, Craig A.

137

Alternathera philoxeroides (Martius) Grisebach - alligator weed  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

138

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.

139

Bio-gas production from alligator weeds  

NASA Technical Reports Server (NTRS)

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

Latif, A.

1976-01-01

140

Potential of fungi for the biological control of some New Zealand weeds  

Microsoft Academic Search

The potential for fungi to control 14 important weeds in New Zealand is reviewed. Information provided includes the fungi already known from these weeds in New Zealand, fungi recorded from the native ranges of the weeds, and past work on the control of these weeds using fungi, both in New Zealand and elsewhere. The 14 weeds are: Berberis spp.; Buddleja

Peter R. Johnston

1990-01-01

141

NITROGEN FERTILIZER AND CROP RESIDUE EFFECTS ON SEED MORTALITY OF EIGHT ANNUAL WEED SPECIES  

Technology Transfer Automated Retrieval System (TEKTRAN)

Weed seed persistence in the soil seedbank plays a central role in weed population dynamics, yet limited knowledge of mechanisms regulating weed seed survival in soil remains an obstacle to developing weed seedbank management practices. Weed seeds are rich in carbon and nitrogen, and therefore may ...

142

South Carolina Pest Management Handbook for Field Crops -2013 WEED CONTROL IN SUNFLOWER  

E-print Network

South Carolina Pest Management Handbook for Field Crops - 2013 249 WEED CONTROL IN SUNFLOWER Mike Marshall, Extension Weed Specialist Preplant/Burndown Herbicides for Weed Management in Sunflowers anytime before planting when weeds are small. Use a higher rate for larger weeds. Add a COC (1-2 gal per

Stuart, Steven J.

143

Research Paper Design and testing of an intra-row mechanical weeding  

E-print Network

As an alternative to chemical weed control, mechanical weed control between crop rows can be achieved using standard the devel- opment of alternative weed control mechanisms to chemical application: Firstly, several weedResearch Paper Design and testing of an intra-row mechanical weeding machine for corn C. Cordill

144

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

Microsoft Academic Search

The aquatic weed situation in the Kafue River in Zambia continues to be a major challenge to the sustainable utilization of the water resources of the river. The general methods for managing the weeds, especially the water hyacinth, include use of bio-agents, chemicals, mechanical and physical approaches. These have had very little impact. This paper reports on a project that

Thomson Sinkala; Enala T Mwase; Mick Mwala

2002-01-01

145

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

Code of Federal Regulations, 2010 CFR

...restrictions on the movement of noxious weeds; permits. 360.300 Section 360...SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.300 General prohibitions...restrictions on the movement of noxious weeds; permits. (a) No person may...

2010-01-01

146

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

Code of Federal Regulations, 2011 CFR

...Petitions to remove a taxon from the noxious weed lists. 360.501 Section 360.501...DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.501 Petitions to remove a taxon from the noxious weed lists. A person may petition...

2011-01-01

147

Noxious Weed Survey of the U.S. Air Force Academy and  

E-print Network

Noxious Weed Survey of the U.S. Air Force Academy and Farish Outdoor Recreation Area Colorado ....................................................................................... 9 WEED MAPPING RATIONALE FOR SUGGESTED MANAGEMENT PRIORITIES IN TABLE 3............................ 13 NOXIOUS WEED STATUS

148

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

Code of Federal Regulations, 2011 CFR

...applications for permits to move noxious weeds. 360.302 Section 360.302 Agriculture...SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.302 Consideration of applications for permits to move noxious weeds. Upon the receipt of an...

2011-01-01

149

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

Code of Federal Regulations, 2014 CFR

...2014-01-01 false Disposal of noxious weeds when permits are canceled. 360.305 ...SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.305 Disposal of noxious weeds when permits are canceled. When a...

2014-01-01

150

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

Code of Federal Regulations, 2013 CFR

...2013-01-01 false Disposal of noxious weeds when permits are canceled. 360.305 ...SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.305 Disposal of noxious weeds when permits are canceled. When a...

2013-01-01

151

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

Code of Federal Regulations, 2012 CFR

...2012-01-01 false Disposal of noxious weeds when permits are canceled. 360.305 ...SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.305 Disposal of noxious weeds when permits are canceled. When a...

2012-01-01

152

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

Code of Federal Regulations, 2014 CFR

...applications for permits to move noxious weeds. 360.302 Section 360.302 Agriculture...SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.302 Consideration of applications for permits to move noxious weeds. Upon the receipt of an...

2014-01-01

153

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

Code of Federal Regulations, 2012 CFR

...applications for permits to move noxious weeds. 360.302 Section 360.302 Agriculture...SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.302 Consideration of applications for permits to move noxious weeds. Upon the receipt of an...

2012-01-01

154

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

Code of Federal Regulations, 2013 CFR

...applications for permits to move noxious weeds. 360.302 Section 360.302 Agriculture...SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.302 Consideration of applications for permits to move noxious weeds. Upon the receipt of an...

2013-01-01

155

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

Code of Federal Regulations, 2012 CFR

...Petitions to remove a taxon from the noxious weed lists. 360.501 Section 360.501...DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.501 Petitions to remove a taxon from the noxious weed lists. A person may petition...

2012-01-01

156

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

Code of Federal Regulations, 2011 CFR

...2011-01-01 false Disposal of noxious weeds when permits are canceled. 360.305 ...SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.305 Disposal of noxious weeds when permits are canceled. When a...

2011-01-01

157

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

Code of Federal Regulations, 2014 CFR

...Petitions to remove a taxon from the noxious weed lists. 360.501 Section 360.501...DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.501 Petitions to remove a taxon from the noxious weed lists. A person may petition...

2014-01-01

158

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

Code of Federal Regulations, 2013 CFR

...of restrictions on movement of noxious weeds. 360.300 Section 360.300 Agriculture...DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.300 Notice of restrictions on movement of noxious weeds. No person may move a Federal...

2013-01-01

159

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

Code of Federal Regulations, 2013 CFR

...Petitions to remove a taxon from the noxious weed lists. 360.501 Section 360.501...DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.501 Petitions to remove a taxon from the noxious weed lists. A person may petition...

2013-01-01

160

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

Code of Federal Regulations, 2014 CFR

...of restrictions on movement of noxious weeds. 360.300 Section 360.300 Agriculture...DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.300 Notice of restrictions on movement of noxious weeds. No person may move a Federal...

2014-01-01

161

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

Code of Federal Regulations, 2012 CFR

...of restrictions on movement of noxious weeds. 360.300 Section 360.300 Agriculture...DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.300 Notice of restrictions on movement of noxious weeds. No person may move a Federal...

2012-01-01

162

Monthly Highlights from Rutgers New Jersey Agricultural Experiment Station January 2009 Weed Control Strategy Differences in  

E-print Network

soil quality with aggressive mechanical tillage and cultivation sufficient for controlling weeds the time and timing challenges faced when pursuing soil health, weed control, mechanical tillage to seeds. Farmers wanting to control weeds with non-chemical herbicide alternatives should

Goodman, Robert M.

163

[Effects of tillage method and herbicide on cornfield weed community].  

PubMed

By the method of community ecology, this paper surveyed the weed community in a cornfield at the Shenyang Experimental Station of Ecology, CAS, and studied the effects of tillage method and herbicide on the weed composition, species diversity, and biomass at the experimental site. The results showed that the dominant weed species in the cornfield were Eriochloa villosa, Abutilon theophrasti, Bidens frondosa and Commelina communis, of which, Eriochloa villosa had the highest important value. In non-tillage field without herbicide application, the weed community had larger biomass, higher richness (S) and concentration (C), but lower species diversity (D) and species evenness (J). Herbicide could decrease weed species and inhibit biomass growth significantly in non-tillage field. It was clear that tillage method and herbicide could affect the weed composition, diversity and stability significantly. PMID:16422507

Liu, Fangming; Liang, Wenju; Wen, Dazhong

2005-10-01

164

Weed selection by sheep grazing dryland lucerne  

Microsoft Academic Search

Diet selection by sheep grazing dryland lucerne with a high proportion of weeds was assessed in two consecutive years (2005\\/2006). The study was performed on 2.66 ha of pasture divided in two homogeneous paddocks subjected to a stocking rate of either 10 or 20 sheep\\/paddock, and grazed for 17 days. Before and after each grazing trial, an inventory was conducted

E. Pérez; A. de Vega; I. Delgado; Y. Pueyo

165

7 CFR 360.200 - Designation of noxious weeds.  

Code of Federal Regulations, 2011 CFR

...wetland weeds: Azolla pinnata R. Brown (mosquito fern, water velvet) Caulerpa taxifolia (Vahl) C. Agardh, Mediterranean strain (killer algae) Eichhornia azurea (Swartz) Kunth Hydrilla verticillata (Linnaeus f.) Royle...

2011-01-01

166

7 CFR 360.200 - Designation of noxious weeds.  

Code of Federal Regulations, 2012 CFR

...wetland weeds: Azolla pinnata R. Brown (mosquito fern, water velvet) Caulerpa taxifolia (Vahl) C. Agardh, Mediterranean strain (killer algae) Eichhornia azurea (Swartz) Kunth Hydrilla verticillata (Linnaeus f.) Royle...

2012-01-01

167

7 CFR 360.200 - Designation of noxious weeds.  

Code of Federal Regulations, 2013 CFR

...wetland weeds: Azolla pinnata R. Brown (mosquito fern, water velvet) Caulerpa taxifolia (Vahl) C. Agardh, Mediterranean strain (killer algae) Eichhornia azurea (Swartz) Kunth Hydrilla verticillata (Linnaeus f.) Royle...

2013-01-01

168

7 CFR 360.200 - Designation of noxious weeds.  

Code of Federal Regulations, 2010 CFR

...a) Aquatic and wetland weeds: Azolla pinnata R. Brown (mosquito fern, water velvet) Caulerpa taxifolia (Mediterranean clone) Eichornia azurea (Swartz) Kunth (anchored waterhyacinth, rooted waterhyacinth) Hydrilla...

2010-01-01

169

7 CFR 360.200 - Designation of noxious weeds.  

Code of Federal Regulations, 2014 CFR

...wetland weeds: Azolla pinnata R. Brown (mosquito fern, water velvet) Caulerpa taxifolia (Vahl) C. Agardh, Mediterranean strain (killer algae) Eichhornia azurea (Swartz) Kunth Hydrilla verticillata (Linnaeus f.) Royle...

2014-01-01

170

REVIEW ARTICLE Innovations in parasitic weeds management in legume crops.  

E-print Network

such as Cuscuta campestris can be damaging for some crops. Here, we review methods to control parasitic weeds . Breeding . Intercropping . Germination . Biological control . Chemical control . Alectra . Cuscuta

Paris-Sud XI, Université de

171

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. PMID:22778701

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

2012-01-01

172

Alternative Strategies for Broadleaf Weed Management in Residential Lawns .  

E-print Network

??Weed management treatments were examined as alternatives to conventional chemical herbicides. Site preparation and post-establishment treatments were tested in a randomized complete block factorial design,… (more)

Siva, Cynthia

2014-01-01

173

Noxious Weed Monitoring at the U.S. Air Force Academy-Year 3 Results  

E-print Network

............................................................................................................. 3 HISTORY OF WEED MAPPING AND MONITORING AT THE ACADEMY................................ 3 WEED repens (Russian Knapweed).................................................................... 13 Cardaria)................................................................ 37 Elaeagnus angustifolia (Russian Olive

174

Integrating Selective Herbicide and Native Plant Restoration to Control Alternanthera philoxeroides (Alligator Weed).  

E-print Network

??Exotic invasive aquatic weeds such as alligator weed (Alternanthera philoxeroides) threaten native ecosystems by interfering with native plant communities, disrupting hydrology, and diminishing water quality.… (more)

Adams, Justin

2011-01-01

175

902 Weed Science 53, NovemberDecember 2005 Weed Science, 53:902908. 2005  

E-print Network

by manipulating plant species and communities to benefit natural enemies of insects and weeds. Such efforts aim to enhance natural enemy impact by providing appro- priate food, shelter, and hosts, and efforts typically viewed as an important factor in maintaining stable insect and natural enemy pop- ulations

Landis, Doug

176

UC Davis Weed Science 1 Brad Hanson, Tom Lanini, and Lynn Sosnoskie, UC Davis Weed Science  

E-print Network

floors are managed for a number of reasons Facilitate crop production and harvest practices Weed water use rates Increased vertebrate and invertebrate pests Enhanced potential for disease Humidity spectrum contact herbicide Labeled in many tree and vine crops Pi d GT l d fl f Pindar GT penoxsulam

Hanson, Brad

177

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

178

SOLARIA HELP PREDICT IN-CROP WEED DENSITIES  

Technology Transfer Automated Retrieval System (TEKTRAN)

At locations in Argentina and USA, solaria (miniature, portable, plastic greenhouses or plastic sheets about 1 m**2) were placed on field soils in autumn or late winter in an attempt to predict summer annual weed densities. Initial emergence of summer annual weeds, covered by solaria commenced weeks...

179

Molecular Biology and Genomics: New Tools for Weed Science  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

180

Image classification approach for automatic identification of grassland weeds  

Microsoft Academic Search

The potential of digital image processing for weed mapping in arable crops has widely been investigated in the last decades. In grassland farming these techniques are rarely applied so far. The project presented here focuses on the automatic identification of one of the most invasive and persistent grassland weed species, the broad-leaved dock (Rumex obtusifolius L.) in complex mixtures of

Steffen Gebhardt; Walter Kühbauch

2006-01-01

181

The role of weeds in the agricultural ecosystem  

Microsoft Academic Search

Although they can be damaging to crop yields and quality, weeds are important components of the agricultural ecosystem. There have been many studies of the relationshop between weeds and other biota, of which the biggest and best known are the Farm Scale Evaluations, undertaken to study the impacts of GM herbicide tolerant crops on biodiversity (Firbank et al ., 2003).

NIGEL BOATMAN

182

DICLOSULAM AND IMAZAPIC COMBINATIONS FOR WEED CONTROL IN GEORGIA PEANUT  

Technology Transfer Automated Retrieval System (TEKTRAN)

Florida beggarweed, sicklepod, wild poinsettia, Palmer amaranth, and morningglories remain troublesome weeds in strip- and conventional tillage systems. The objectives of this study were to determine the effect of diclosulam and imazapic combinations on peanut weed control and yield in cropping sit...

183

Weed seed predation in organic and conventional fields  

Microsoft Academic Search

Enhanced biological control of weed seeds may improve sustainability of agricultural production. Biological control due to seed predation may be higher in organic fields because organic production generally supports more seed predators. To investigate such a difference, weed seed predation was studied in autumn in eight organic and eight conventional mixed cropping fields in New Zealand. Predation rates were estimated

S. Navntoft; S. D. Wratten; K. Kristensen; P. Esbjerg

2009-01-01

184

ALLELOPATHY FOR WEED CONTROL IN AQUATIC AND WETLAND SYSTEMS  

Technology Transfer Automated Retrieval System (TEKTRAN)

This book chapter briefly summarizes role of allelopathy for weed control in aquatic and wetlands. Plants can interfere with each other through allelopathy or competition for resources. Allelopathy can be used in weed management in several ways including cover crops, smother crops, green manure crop...

185

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

186

COMPETITION BETWEEN GREEN PEA AND ITS SUMMER ANNUAL WEEDS  

Microsoft Academic Search

Most weed species can take up nitrogen and potassium from soil at a higher degree than crop plant living in association with it. Nutrient concentration in dry matter of plants indicates nutrient requirement. In our experiment we are looking for the answer how distributed nitrogen, phosphorus and potassium uptaken from soil among pea and its weeds. Pot competition experiment was

Nádasy Erzsébet

187

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...

188

Working the Educational Soil and Pulling Up Weeds  

ERIC Educational Resources Information Center

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

Riggins-Newby, Cheryl

2005-01-01

189

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.

190

Weeds of the Midwestern United States and Central Canada  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

191

Deciphering the evolution of herbicide resistance in weeds  

E-print Network

Deciphering the evolution of herbicide resistance in weeds Christophe De´lye1 , Marie Jasieniuk2, University of California, Davis, CA 95616, USA Resistance to herbicides in arable weeds is increasing rapidly worldwide and threatening global food securi- ty. Resistance has now been reported to all major herbicide

California at Davis, University of

192

Susceptibility of some common container weeds to Phytophthora ramorum  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

193

RESEARCH ARTICLE Biodegradable mulch instead of polyethylene for weed  

E-print Network

of biodegradable plastic mulch, black, 15 m, (6) oxo-degradable plastic mulch, black, 15 m, (7) paper mulch, black.3 to 4.4 t ha-1 for each 10% of efficacy loss. Weed control was high for biodegradable plastics, paper be an alternative. Keywords Polyethylene . Biodegradable mulch . Paper. Barley straw 1 Introduction Weeds

Paris-Sud XI, Université de

194

Selective uprooting by weed harrowing on sandy soils  

Microsoft Academic Search

Uprooting by weed harrowing and the potential of the uprooting process for selective weed control at early crop growth stages was studied. Effects of working depth, seed depth, soil moisture content and working speed on uprooting of Lolium perenne L., Lepidium sativum L. and Chenopodium quinoa Willd. were investigated in laboratory harrowing experiments on a sandy soil. Harrowing uprooted on

D. A. G. Kurstjens; U. D. Perdok; D. Goense

2000-01-01

195

Horticultural & Forest crops 2014 Turf: Weeds 6-37  

E-print Network

Horticultural & Forest crops 2014 Turf: Weeds 6-37 Weeds Shawn D. Askew, Associate Professor, Virginia Tech Weedy Grasses there are several preemergence crabgrass killers available which will do herbicide application in May or June is suggested for best results. preemergence crabgrass killers kill

Liskiewicz, Maciej

196

The Importance of Intertrophic Interactions in Biological Weed Control  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

197

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

SciTech Connect

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

Schiller, D.H.

1984-06-01

198

WEED SEED MORTALITY IN SOILS WITH CONTRASTING AGRICULTURAL HISTORIES  

Technology Transfer Automated Retrieval System (TEKTRAN)

Conservation biocontrol has been proposed as a means of directly reducing weed seedbanks. In this approach, cropping systems are managed to enhance degradation of weed seeds by soil microbes. We examined the relationship between long-term agricultural management practices, soil fungal and bacterial ...

199

Impact of weed barriers on newly planted peach trees  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

200

Weed science research and funding: a call to action  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

201

Addressing current and future problems of parasitic weeds in rice  

Microsoft Academic Search

Significant areas of rain-fed rice in the Sahel, savannah and derived savannah zones of sub-Saharan Africa (SSA), Madagascar and other Indian Ocean Islands are infested by parasitic weeds. The affected area accommodates some of the poorest farmers of the world. Without appropriate management parasitic weeds in rice are expected to increase in importance in SSA due to their general invasive

Jonne Rodenburg; Charles R. Riches; Juma M. Kayeke

2010-01-01

202

Hyperspectral image sensor for weed-selective spraying  

NASA Astrophysics Data System (ADS)

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

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

1999-11-01

203

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

204

Natural compounds for pest and weed control.  

PubMed

The control of insect pests and invasive weeds has become more species-selective because of activity-guided isolation, structure elucidation, and total synthesis of naturally produced substances with important biological activities. Examples of isolated compounds include insect pheromones, antifeedants, and prostaglandins, as well as growth regulators for plants and insects. Synthetic analogues of natural substances have been prepared to explore the relationships between chemical structure and observed biological activity. Recent scientific advances have resulted from better methods for the chemical synthesis of target compounds and better analytical methods. The capability of analytical instrumentation continues to advance rapidly, enabling new insights. PMID:19719128

Petroski, Richard J; Stanley, David W

2009-09-23

205

Weed Control Research in Sugar Beets.  

E-print Network

BULLETIN ' THE TEXAS AGRICULTURAL EXPERIMENT STATION1 J. E. Miller, Director1 Texas A&M University1 College Station, Texas r B-1158 November 1975 WEED CONTROL RESEARCH IN SUGAR BEETS A. F. Wiese, P. R. Scott, D. E. Lavake, S. R. Winter and D.... F. Owen* Total sugar beet acreage in the Texas Panhandle Service, Bushland; Holly Sugar Corporation, has paried from 20,000 to 40,000 acres since Holly Hereford; Texas Tech Center, Pantex; and farmers in Sugar Corporation started operations...

Wiese, A. F.; Scott, P. R.; Lavake, D. E.; Winter, S. R.; Owen, D. F.

1975-01-01

206

Weed Busters: How to Neutralize Silverleaf Nightshade  

E-print Network

by spraying with a mixture of 1 percent Grazon P+D?, Weedmaster?, or Range Star? in water. To prepare the spray mixture, fill the spray tank half full of water and add the desired amount of herbicide and surfactant. Then continue to fill the tank with water... ounces Dye 1 /4%1 ounce 5 ounces 8 ounces All spray solutions are mixed in water. Grazon P+D? 1-1.5 quarts Weedmaster? 1 quart Range Star? 1 quart 1-2 quarts per 100 gallons of 10-30 water gallons/acre S ilverleaf nightshade can be a serious weed problem...

2005-03-07

207

Weed hosts of Verticillium dahliae in cotton fields in Turkey and characterization of V. dahliae isolates from weeds  

Microsoft Academic Search

A weed survey conducted in 2004 and 2005 in Aydin province of Turkey showed that Solanum nigrum, Xanthium strumarium, Amaranthus retroflexus, Portulaca oleracea, Sonchus oleraceus and Datura stramonium were the most prevalent weeds in the cotton fields exhibiting Verticillium wilt. Verticillium dahliae Kleb. was recovered from A. retroflexus and X. strumarium in those cotton fields. This is the first report

Ayhan Yildiz; M. Nedim Do?an; Özhan Boz; Seher Benlio?lu

2009-01-01

208

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

209

ENVIRONMENTAL FACTORS AFFECTING SEED PERSISTENCE OF 13 ANNUAL WEEDS ACROSS THE U.S. CORN BELT  

Technology Transfer Automated Retrieval System (TEKTRAN)

Weed seedbanks have been studied intensively at local scales, but to date there have been no regional scale studies of weed seedbank persistence. Empirical and modeling studies indicate that reducing weed seedbank persistence can play an important role in integrated weed management. Annual seedbank ...

210

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.

211

South Carolina Pest Management Handbook for Field Crops -2014 WEED CONTROL IN PEANUT  

E-print Network

South Carolina Pest Management Handbook for Field Crops - 2014 163 WEED CONTROL IN PEANUT Mike Marshall, Extension Weed Specialist Preplant/Burndown Herbicides for Weed Management in Peanut Herbicide Management Handbook for Field Crops - 2014 164 Preplant/Burndown Herbicides for Weed Management in Peanut

Duchowski, Andrew T.

212

South Carolina Pest Management Handbook for Field Crops -2013 WEED CONTROL IN PEANUT  

E-print Network

South Carolina Pest Management Handbook for Field Crops - 2013 152 WEED CONTROL IN PEANUT Mike Marshall, Extension Weed Specialist Preplant/Burndown Herbicides for Weed Management in Peanut Herbicide/Burndown Herbicides for Weed Management in Peanut (cont) Herbicide Rate/Acre Broadcast Mode of Action Preharvest

Stuart, Steven J.

213

South Carolina Pest Management Handbook for Field Crops -2014 WEED CONTROL IN TOBACCO  

E-print Network

South Carolina Pest Management Handbook for Field Crops - 2014 270 WEED CONTROL IN TOBACCO Mike Marshall, Extension Weed Specialist Preplant (Incorporated) Herbicides for Weed Management in Tobacco Pretransplant (Surface Applied) Herbicides for Weed Management in Tobacco Herbicide Rate/Acre Broadcast Mode

Duchowski, Andrew T.

214

South Carolina Pest Management Handbook for Field Crops -2013 WEED CONTROL IN TOBACCO  

E-print Network

South Carolina Pest Management Handbook for Field Crops - 2013 257 WEED CONTROL IN TOBACCO Mike Marshall, Extension Weed Specialist Preplant (Incorporated) Herbicides for Weed Management in Tobacco for Weed Management in Tobacco Herbicide Rate/Acre Broadcast Mode of Action Preharvest Interval Restricted

Stuart, Steven J.

215

Integrating management techniques to restore sites invaded by mile-a-minute weed, Persicaria perfoliata  

Technology Transfer Automated Retrieval System (TEKTRAN)

Efforts to suppress an invasive weed are often undertaken with the goal of facilitating the recovery of a diverse native plant community. In some cases, however, reduction in the abundance of the target weed results in an increase in other exotic weeds. Mile-a-minute weed, Persicaria perfoliata (L.)...

216

South Carolina Pest Management Handbook for Field Crops -2013 WEED CONTROL IN COTTON  

E-print Network

South Carolina Pest Management Handbook for Field Crops - 2013 63 WEED CONTROL IN COTTON Mike Marshall, Extension Weed Specialist Preplant Burndown Herbicides for Weed Management in Cotton Herbicide any time prior to planting. For best results, apply to weeds that are less than 4 inches tall (less

Stuart, Steven J.

217

South Carolina Pest Management Handbook for Field Crops -2013 WEED CONTROL IN SOYBEAN  

E-print Network

South Carolina Pest Management Handbook for Field Crops - 2013 205 WEED CONTROL IN SOYBEAN Mike Marshall, Extension Weed Specialist Preplant/Burndown Herbicides for Weed Management in Soybean Herbicide time before planting. For best results, apply when weeds are less than 4 inches tall (less than 3 inch

Stuart, Steven J.

218

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. PMID:23962298

2013-01-01

219

Wallowa Canyonlands Weed Partnership : Completion Report November 19, 2009  

SciTech Connect

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

Porter, Mark C.; Ketchum, Sarah

2008-12-30

220

Capabilities of unmanned aircraft vehicles for low altitude weed detection  

NASA Astrophysics Data System (ADS)

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

Pflanz, Michael; Nordmeyer, Henning

2014-05-01

221

A Tale of Two Depositories: Weeding Federal Depository Collections  

E-print Network

be weeded. Up to that time, only revised titles listed in the Superseded List (purl.access.gpo. gov/GPO/LPS22813) had been weeded on a limited basis. I was familiar with the federal depository print collection because I had recently helped shift many... the col- lection, and items not superseded had to be offered to other depository libraries before withdrawing (purl.access.gpo.gov/ GPO/LPS89341, Chapter 5.14). After establishing what not to weed, criteria for items for removal were created. Because...

Sare, Laura

2009-01-01

222

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

NASA Astrophysics Data System (ADS)

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

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

223

Microbial weeds in hypersaline habitats: the enigma of the weed-like Haloferax mediterranei.  

PubMed

Heterotrophic prokaryotic communities that inhabit saltern crystallizer ponds are typically dominated by two species, the archaeon Haloquadratum walsbyi and the bacterium Salinibacter ruber, regardless of location. These organisms behave as 'microbial weeds' as defined by Cray et al. (Microb Biotechnol 6: 453-492, 2013) that possess the biological traits required to dominate the microbiology of these open habitats. Here, we discuss the enigma of the less abundant Haloferax mediterranei, an archaeon that grows faster than any other, comparable extreme halophile. It has a wide window for salt tolerance, can grow on simple as well as on complex substrates and degrade polymeric substances, has different modes of anaerobic growth, can accumulate storage polymers, produces gas vesicles, and excretes halocins capable of killing other Archaea. Therefore, Hfx. mediterranei is apparently more qualified as a 'microbial weed' than Haloquadratum and Salinibacter. However, the former differs because it produces carotenoid pigments only in the lower salinity range and lacks energy-generating retinal-based, light-driven ion pumps such as bacteriorhodopsin and halorhodopsin. We discuss these observations in relation to microbial weed biology in, and the open-habitat ecology of, hypersaline systems. PMID:25132231

Oren, Aharon; Hallsworth, John E

2014-10-01

224

continuedonthenextpage... Guide to Common Weeds in Lawns in California  

E-print Network

to Common Weeds in Lawns in California Yellow nutsedge Perennial. Sprouts from tubers in spring; dies back and drainage, and apply postemergent herbicides before the 5-leaf stage. Purple nutsedge Perennial that sprouts

Ishida, Yuko

225

Cultural control of weeds in herbicide-free annual forages  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

226

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...

227

Appearance of Herbicide Resistance in a Weed Population  

NSDL National Science Digital Library

Through the repeated use of the same herbicide, weed populations can consist of susceptible (S)-biotypes that are controlled and herbicide resistant (R)-biotypes that are left behind to produce and return seed with the resistance characteristic back into the soil. This lesson will highlight the population dynamics of a mixed weed population, containing S- and R-biotypes, and compare and contrast the rate at which herbicide resistant weeds appear in a population under a diversity of selection pressures. This lesson will highlight the population dynamics of a mixed (herbicide susceptible and resistant biotype) weed population, and compare and contrast the rate of appearance of herbicide resistance in a mixed population under a diversity of selection pressures.

228

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

ERIC Educational Resources Information Center

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

Myers, Arthur L.

229

Nevada's Noxious Weed Program Nevada Department of Agriculture  

E-print Network

for humans · Loss of grazing lands for both livestock and native animals #12;Brief history: (NV laws were???? Education, education, education..... Schools, NV Assoc. of Counties, Parks & Rec., Weed Warriors Classes County Lovelock Valley Paradise Valley W

Nowak, Robert S.

230

Protecting the Environment Using Integrated Weed Management in Lawns  

E-print Network

application. Surface water can become contaminated with turfgrass Protecting the Environment Using Integrated Weed Management in Lawns Mary L. Ketchersid and Paul A. Baumann* herbicides that are easily dissolved in water and used near hard surfaces...

Ketchersid, Mary; Baumann, Paul A.

2008-03-27

231

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

2013-09-01

232

Locoine, the Poisonous Principle of Loco Weed, Astragalus earlei.  

E-print Network

TEXAS AGRICULTURAL EXPERIMENT STATION A. B. CONMER, DIRECTOR COLLEGE STATIONp BRAZOS COUNTY* TEXAS RULLETIN NO. 53 7 NOVEMBER, 1936 DIVISION OF CHEMISTRY LOCQINE, THE POISONOUS PRINCIPLE OF LOCO WEED Astragalus Earlei LTBRARY 1(\\flc... weed Astragalus *lei. The toxic principle has been given the name locoine. has been isolated by a long series of chemical separations, :h separation being tested by feeding to cats. It is a strong se, very soluble in water a.nd alcohol, but only...

Fraps, G. S. (George Stronach); Carlyle, E. C. (Elmer Cardinal)

1936-01-01

233

Chemical Weed Control in Japanese Mint (Mentha arvensis L.)  

Microsoft Academic Search

Field investigations were carried out during 1987 and 1988 to compare cultural and chemical control of broad leaf and grass weeds present in the first and second harvest of Japanese mint. Unrestricted weed growth significantly reduced mint oil yield by 58% and 73%, respectively in the first and second harvests. Preemergence applications of terbacil (1.5 kg a.i.\\/ha), pendimethalin (1.0 kg

S. K. Kothari; K. Singh

1994-01-01

234

Cover crop residue management for optimizing weed control  

Microsoft Academic Search

Although residue management seems a key factor in residue-mediated weed suppression, very few studies have systematically\\u000a compared the influence of different residue management strategies on the establishment of crop and weed species. We evaluated\\u000a the effect of several methods of pre-treatment and placement of winter rye (Secale cereale L.) and winter oilseed rape (Brassica napus L.) residue on seedling emergence

H. Marjolein Kruidhof; Lammert Bastiaans; Martin J. Kropff

2009-01-01

235

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). PMID:22163954

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

2011-01-01

236

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

2011-01-01

237

Weed control in glyphosate-tolerant maize in Europe.  

PubMed

Maize growing in the EU27 increased to over 13 million ha in 2007, most of which (>80%) was grown in just eight countries (France, Romania, Germany, Hungary, Italy, Poland, Spain and Bulgaria). The number of herbicides used to control the wide spectrum of weeds occurring in all these countries is likely to decline in the future as each current active ingredient is reassessed for toxicological and environmental safety under Directive 91/414/EEC. Glyphosate has already been approved under this directive. Glyphosate, applied alone or in combination with currently available residual herbicides to genetically modified varieties tolerant to glyphosate, can provide a viable, flexible and profitable alternative to conventional weed control programmes. Glyphosate usage with glyphosate-tolerant varieties also provides an environmentally sustainable weed control option as long as sufficient diversity of weed management options (crop rotation, chemical diversity, multiple cultural and mechanical practices, buffer strips) is maintained within the farm management system. Appropriate product stewardship measures will be required to maximise the long-term overall benefits of the glyphosate-based system. Specifically, care will need to be taken to manage potential weed shifts to more difficult-to-control species and to reduce the risk of selection for glyphosate-resistant weeds. PMID:19557724

Dewar, Alan M

2009-10-01

238

Weed seedbank evaluating method to generate spatial distribution maps.  

PubMed

The objective of this work was to develop a fast and practical method of weed seedbank evaluation to generate spatially distributed maps for use in site-specific weed management. Soil cores were collected at 0.20 m depth, air-dried, and then submitted to seedling growth in greenhouse. The sampling grid of 20 by 20 m was georeferenced by Global Positioning System, obtaining 73 soil cores with three replicates. During the greenhouse trial, there were two peaks of weed seedling growth: one in 119 days after water irrigation and another after KNO3 application. Weeds seedbank maps were obtained at different stages of seedling growth. The Pearson correlation was 0.99 for Brachiaria plantaginea seedbank map, 0.95 for Commelina benghalensis, and 0.85 for Cyperus rotudus generated at 119 days compared with 392 days after seedling growth in the greenhouse. The Brachiaria plantaginea seedbank map evaluated at 35 days presented correlation of 0.97 with 392 days. It was concluded that, for site-specific weed seedbank management, the evaluation of seedling growth in greenhouse until the first emergence peak is enough to generate weed seedbank maps. PMID:15656180

Shiratsuchi, Luciano Shozo; Antoniol, Fontes-José Roberto; Rocha, Silva-Rodrigo

2005-01-01

239

Preplant weed management and planting date influence yield, water use, and weed seed production in herbicide-free forage barley  

Technology Transfer Automated Retrieval System (TEKTRAN)

In semiarid regions, the adoption of zero tillage improves soil water conservation, allowing for increased crop intensification and diversification. Zero tillage crop production relies heavily on herbicides for weed management, particularly the herbicide glyphosate, increasing selection pressure fo...

240

Division of Agricultural Sciences and Natural Resources Oklahoma State University Weed Control in Christmas tree plantations is one of  

E-print Network

,duringthetimecompetition forwaterandnutrientsismostcritical. Weed Control After Planting Mechanical MechanicalmethodstocontrolweedsincludecultivationDivision of Agricultural Sciences and Natural Resources · Oklahoma State University Weed Control.Weedscompeteforwater,nutrients,andlight andextendthetimerequiredtoproduceamarketabletree. Successful weed control helps the grower produce high

Balasundaram, Balabhaskar "Baski"

241

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

242

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

Federal Register 2010, 2011, 2012, 2013, 2014

...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

243

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

Code of Federal Regulations, 2011 CFR

... Notice of restrictions on movement of noxious weeds. 360... Notice of restrictions on movement of noxious weeds. No...approved; and (c) The movement is consistent with the specific...Management and Budget under control number 0579-0054)...

2011-01-01

244

Horticultural & Forest crops 2014 Floral Crops: Weed Control in Greenhouses 5-37  

E-print Network

Horticultural & Forest crops 2014 Floral Crops: Weed Control in Greenhouses 5-37 Weed Control postemergence herbicide. Do not allow spray to contact desired plants. #12;Horticultural & Forest crops 2014 5

Liskiewicz, Maciej

245

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

246

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

247

(9/12) Pistachio Weed Survey Form 1 Download at www.ipm.ucdavis.edu/FORMS  

E-print Network

(9/12) Pistachio Weed Survey Form 1 Download at www.ipm.ucdavis.edu/FORMS www.ipm.ucdavis.edu Pistachio Weed Survey Form Supplement to UC IPM Pest Management Guidelines Grower or Orchard, Italian W+B+P sprangletops S witchgrass S Perennial Grasses bermudagrass P #12;(9/12) Pistachio Weed

Ishida, Yuko

248

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...

249

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

250

ROLE OF SWEET CORN CANOPY ARCHITECTURE IN CROP/WEED INTERACTIONS  

Technology Transfer Automated Retrieval System (TEKTRAN)

: Sweet corn canopy architecture influences crop tolerance (CT) to weed interference and the crop’s suppressive ability (WSA) of weed growth and fecundity. A quantitative analysis of specific traits responsible for CT and WSA could enhance the impact of hybrid characteristics on weed management in...

251

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

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Noxious-weed seeds in the District of Columbia. 201...Agricultural Seeds § 201.17 Noxious-weed seeds in the District of Columbia. (a) Noxious-weed seeds in the District of Columbia are:...

2010-01-01

252

Airborne hyperspectral and LiDAR data integration for weed detection  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

253

7 CFR 201.65 - Noxious weed seeds in interstate commerce.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Noxious weed seeds in interstate commerce. 201...REGULATIONS Tolerances § 201.65 Noxious weed seeds in interstate commerce. Tolerances for rates of occurrence of noxious-weed seeds shall be recognized and shall...

2010-01-01

254

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.

255

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

256

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

257

Machine Vision System for Automatic Weeding Strategy using Image Processing Technique  

Microsoft Academic Search

The most widely used method for weed control is to use agricultural chemicals (herbicides products). This heavy reliance on chemicals raises many environmental and economic concerns, causing many plantation companies to seek alternatives for weed control in order to reduce chemical usage in their plantation. Since manual labor is costly and expensive, an automated weed control system may be economically

Kamarul Hawari Ghazali; Aini Hussain

2008-01-01

258

UNITED STATES DEPARTMENT OF AGRICULTURE - AGRICULTURAL RESEARCH SERVICE RESEARCH ON PEST BIOLOGY: WEEDS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Over 125 permanent full-time scientists conduct research within ARS on issues related to weeds. The research emphasis of most of these scientists involves ecology and management or biological control of weeds. Many scientists perform research on weed biology as components of their primary projects o...

259

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

260

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

261

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

262

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

Code of Federal Regulations, 2012 CFR

...applications for permits to move noxious weeds. 360.301 Section 360.301 Agriculture...SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.301 Information...applications for permits to move noxious weeds. (a) Permit to import a noxious...

2012-01-01

263

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

Code of Federal Regulations, 2014 CFR

...applications for permits to move noxious weeds. 360.301 Section 360.301 Agriculture...SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.301 Information...applications for permits to move noxious weeds. (a) Permit to import a noxious...

2014-01-01

264

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

Code of Federal Regulations, 2014 CFR

...2014-01-01 2014-01-01 false Noxious-weed seeds in interstate commerce. 201...REGULATIONS Tolerances § 201.65 Noxious-weed seeds in interstate commerce. Tolerances for rates of occurrence of noxious-weed seeds shall be recognized and shall...

2014-01-01

265

7 CFR 201.65 - Noxious weed seeds in interstate commerce.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 2011-01-01 false Noxious weed seeds in interstate commerce. 201...REGULATIONS Tolerances § 201.65 Noxious weed seeds in interstate commerce. Tolerances for rates of occurrence of noxious-weed seeds shall be recognized and shall...

2011-01-01

266

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

Code of Federal Regulations, 2012 CFR

...2012-01-01 2012-01-01 false Noxious-weed seeds in interstate commerce. 201...REGULATIONS Tolerances § 201.65 Noxious-weed seeds in interstate commerce. Tolerances for rates of occurrence of noxious-weed seeds shall be recognized and shall...

2012-01-01

267

South Carolina Pest Management Handbook for Field Crops -2013 AQUATIC WEED CONTROL  

E-print Network

South Carolina Pest Management Handbook for Field Crops - 2013 284 AQUATIC WEED CONTROL Jack M. Whetstone, Extension Aquatic Specialist W. Cory Heaton, County Agent Aquatic weeds in ponds or lakes can will depend on factors such as target weeds, non-target plants, and what the water is used for. Physical

Stuart, Steven J.

268

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

Code of Federal Regulations, 2011 CFR

...applications for permits to move noxious weeds. 360.301 Section 360.301 Agriculture...SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.301 Information...applications for permits to move noxious weeds. (a) Permit to import a noxious...

2011-01-01

269

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

Code of Federal Regulations, 2013 CFR

...applications for permits to move noxious weeds. 360.301 Section 360.301 Agriculture...SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.301 Information...applications for permits to move noxious weeds. (a) Permit to import a noxious...

2013-01-01

270

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

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Noxious-weed seeds in interstate commerce. 201...REGULATIONS Tolerances § 201.65 Noxious-weed seeds in interstate commerce. Tolerances for rates of occurrence of noxious-weed seeds shall be recognized and shall...

2013-01-01

271

11:776:402 Weeds: Impact & Management in Urban Landscapes (WIMUL) (3 credits)  

E-print Network

11:776:402 Weeds: Impact & Management in Urban Landscapes (WIMUL) (3 credits) Normally OfferedCompanion Description: This is a senior level course which, in three modules, examines the impact of weeds in urban.); industrial sites; rights of way (rails & roads); etc. Module 1 of WIMUL covers the basic principles of weed

Chen, Kuang-Yu

272

Nitrogen Fertilizer and Crop Residue Effects on Seed Mortality and Germination of Eight Annual Weed Species  

E-print Network

. Mechanisms underlying soil N fertility effects on weed seed mortality appear to be species-specific. Future control over the genetics of weed populations, a moderate amount of control over the maternal environmentNitrogen Fertilizer and Crop Residue Effects on Seed Mortality and Germination of Eight Annual Weed

Sims, Gerald K.

273

Evolution of Weediness and Invasiveness: Charting the Course for Weed Genomics  

E-print Network

, and mechanisms of control. In much the same way, genomic approaches promise to extend our insights againEvolution of Weediness and Invasiveness: Charting the Course for Weed Genomics C. Neal Stewart, Jr these important features of weed biology. However, the genomic tools and resources available for weed research

Rieseberg, Loren

274

WeedManagement 464 AgronomyJournal Volume102,Issue2 2010  

E-print Network

. Total weed control in most vegetable crops is difficult to obtain, despite extensive targeting of weed seedlings with mechanical and chemical control tactics. Over one-half of sweet corn fields suffer yield loss, Williams et al., 2008). Such high yield losses may justify additional expense for control of a low weed

Sims, Gerald K.

275

WEED MANAGEMENT IN SHELTERBELTS IS important as unwanted plants can compete for moisture,  

E-print Network

availability often limit plant growth. Pre-planting weed control Weed control is much easier to accomplish, it is essential to effectively control perennial weed species as they are extremely difficult to control after rhizomatous or stoloniferous habits and mechanical control such as cultivation or tillage can spread them

Maxwell, Bruce D.

276

Managing Weeds in Lentils In recent years there has been increased interest in  

E-print Network

a viable alternative for organic producers. Producers should be aware that mechanical weed control not be enough to secure adequate weed control in lentil fields. More information on cultural considerations and variety selection can be found in the Montguide, Growing Lentils in Montana (MT199615AG) Mechanical weed

Maxwell, Bruce D.

277

Broadleaf weeds and sugar beet response to phenmedipham, desmedipham, ethofumesate and triflusulfuron-methyl  

Microsoft Academic Search

The sugar beet plant is a poor competitor against weeds. Uncontrolled weeds that emerge with the crop typically cause from 50 to 100% yield loss. Field studies were conducted from 2002-2004 to investigate the effects of different rates (1\\/1, ľ, ˝) of herbicides on broadleaf weed control and yield of sugar beet. Phenmedipham + desmedipham + ethofumesate, triflusulfuron, metamitron, chloridazon,

V. Seibutis

278

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...

279

Decomposition dynamics of invasive alligator weed compared with native sedges in a Northland lake  

Microsoft Academic Search

Invasive weeds have been shown to alter ecosystem processes such as decomposition and nutrient cycling. However, little is known about the effects of introduced biocontrol agents on these processes. This study examined the effects of alligator weed (Alternanthera philoxeroides) and its biocontrol agent, the alligator weed flea beetle (Agasicles hygrophila), on nutrient cycling in a northern New Zealand lake. Alligator

Imogen E. Bassett; Jacqueline R. Beggs; Quentin Paynter

2010-01-01

280

Changes in weed composition of winter wheat crops due to long-term fertilization  

Microsoft Academic Search

The effects of various fertilization levels on weed species composition and aboveground biomass were investigated in experimental plots of winter wheat established 14 years ago in Fengqiu, China. The treatments examined influenced weeds growth, the effects differing much between weed species. Arenaria serpyllifolia, Chorispora tenella, Erysimum cheiranthoides, and Veronica persica were best adapted either to N-, P-, K-deficiency or balanced

Lichu Yin; Zucong Cai; Wenhui Zhong

2005-01-01

281

Cover crops and interrow tillage for weed control in short season maize ( Zea mays)  

Microsoft Academic Search

Weed competition can cause substantial maize (Zea mays L.) yield reductions. Interseeding maize with cover crops or a combination of interrow cultivation and interseeded cover crops are possible alternative methods of weed control. This study was conducted to examine the potential of interrow cultivation plus cover crops to reduce weed density in maize without reducing the grain yield. Field experiments

O. A. Abdin; X. M. Zhou; D. Cloutier; D. C. Coulman; M. A. Faris; D. L. Smith

2000-01-01

282

The possible role of weed races in the evolution of cultivated plants  

Microsoft Academic Search

Most of our cultivated plants have companion weed races. This phenomenon is so common that it must have some biological significance. In some cases the weeds are the progenitors of the crops, but in many cases we must look for something that could give rise to both the weed forms and the cultivated form together.

Jack R. Harlan

1965-01-01

283

Weed populations and crop rotations : Exploring dynamics of a structured periodic system  

Microsoft Academic Search

The periodic growing of a certain set of crops in a prescribed order, called a crop rotation, is considered to be an important tool for managing weed populations. Nevertheless, the effects of crop rotations on weed population dynamics are not well understood. Explanations for rotation effects on weed populations usually invoke the diversity of environments caused by different crops that

Shana K. Mertens; Frank van den Bosch

2002-01-01

284

The effect of environmental conditions on the seasonal dormancy pattern and germination of weed seeds  

Microsoft Academic Search

Weeds cause considerable losses in horticultural and agricultural crops. Weeds are still predominantly controlled with herbicides. To reduce the use of chemicals, a better understanding of the biology of weeds is required. In this thesis the effect of environmental conditions on dormancy and germination of Chenopodium album L., Polygonum persicaria L., P. lapathifolium L. subsp. lapathifolium, Sisymbrium officinale (L.) Scop.

H. J. Bouwmeester

1990-01-01

285

The Effect of Farmyard Manure Anaerobic Treatment on Weed Seed Viability  

Microsoft Academic Search

Weed encroachment is a serious problem of contemporary agriculture. Farmyard manure and other organic fertilizers can be major sources of weed seeds that get into the soil. One of the methods for eliminating weed seed germination is the technology of anaerobic treatment of the farmyard manure with a simultaneous production of biogas, the so called “Olomouc method”.Before anaerobic fermentation seeds

B. Šarapatka; M. Holub; M. Lhotská

1993-01-01

286

Phenological observations on shrubs to predict weed emergence in turf.  

PubMed

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. PMID:15846520

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

2005-09-01

287

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

288

Image classification approach for automatic identification of grassland weeds  

NASA Astrophysics Data System (ADS)

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

Gebhardt, Steffen; Kühbauch, Walter

2006-08-01

289

Strategies for non-chemical weed control on public paved areas in Denmark.  

PubMed

To be proactive in minimizing pesticide use, the public authorities in Denmark agreed in 1998 to phase out the use of pesticides on publicly owned areas by the end of 2002. A part of the agreement was an increasing focus on research into and development of new methods and implements for non-chemical weed control on paved areas. Due to a large increase in the costs of non-chemical weed control, the park authorities have to put the different types and locations of paved areas in order of priority to optimize the weed control effort. The present authors divided the paved areas into five weed control levels, dependent on placement, quality and use. For the 3 years 1999-2001, experiments with different non-chemical weed control methods were conducted on pavements at six locations in Denmark. The aim was to test the reaction of the weeds to different treatments and strategies. The efficacies of the methods were evaluated by analysis of digital images to estimate the fraction of the paved area covered with green vegetation (weed coverage). The weed coverage was used as the dependent variable in the subsequent statistical analysis. The independent variables in the model were incoming radiation, wear, area of joints in the pavement, the dying process of the weeds and the number of runs/applied energy of the mechanical or thermal weed control methods, respectively. The estimated parameters from the statistical model were used to build a simulation model, which was used to optimise five weed control strategies to fulfil the suggested weed control levels. In the suggested strategy for maximum weed control, 12 thermal weeding applications at 2-week intervals are suggested. The 'clean-up' strategy is based on one weed-brushing in late spring or early autumn. PMID:15198334

Hansen, Preben K; Kristoffersen, Palle; Kristensen, Kristian

2004-06-01

290

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

PubMed

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

Lehoczky, E; Reisinger, P

2003-01-01

291

Suggestions for Chemical Weed and Brush Control on Rangeland.  

E-print Network

plant Broadcast Common name of Individual plant Broadcast weed species or spot treatment treatment brush species or spot treatment treatment Berlandier lobelia 5 5 ChoIIa 10 Bitter sneezeweed 5 5 Common persimmon 13,13 13 Broomweed (annual or common... or spot individual controlled chemical names) per acre treatment plant) Time to apply Remarks Berlandier lobelia, 2,4-0 amine or I pt to I qt I gal (4 Ib) 2 to 4 gal Spring, weed 4 Use 2,4-0 amine in areas bitter sneezeweed, low volatile (1/2 to lib) 4...

Welch, Tommy G.

1988-01-01

292

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

293

Artemisia biennis (biennial wormwood) control is influenced by plant size and weed flora at time of herbicide application  

Microsoft Academic Search

Artemisia biennis has become a major weed of several crops within the northern Great Plains of the US and Prairie Provinces of Canada. It is expanding its habitat range and is now a problem weed across the North Central region of the United States. Field and greenhouse studies were conducted to evaluate the role of weed size, weed flora, and

George O. Kegode; Bradley E. Fronning

2005-01-01

294

Long-term effects of weed control and fertilization on the carbon and nitrogen pools of a  

E-print Network

Long-term effects of weed control and fertilization on the carbon and nitrogen pools of a slash. Jokela Abstract: The effects of fertilization, weed control, and fertilization plus weed control accumulated in fertilized forests without weed control was 20% (slash pine) and 40% (loblolly pine) greater

Martin, Timothy

295

Occurrence of the new invasive insect Contarinia nasturtii (Diptera: Cecidomyiidae) on cruciferous weeds.  

PubMed

Contarinia nasturtii (Kieffer) (Diptera: Cecidomyiidae), a common insect pest in Europe and a new invasive pest in North America, causes severe damage to cruciferous crops. In the United States, C. nasturtii was first reported in western New York in 2004. From 2005 to 2007, field surveys were conducted in western New York to investigate the occurrence of C. nasturtii in weeds that might serve as a reservoir for this pest. The results indicate that 12 cruciferous weed species were found in and around commercial vegetable crucifer plantings, and C. nasturtii emergence was detected from most of them. The number of C. nasturtii that emerged from the weeds was low and varied by species, year, and the timing of sampling. Peak emergence from weeds in fallow fields occurred in June. Nonchoice tests in the laboratory showed that significantly fewer larvae were found on cruciferous weeds than on cauliflower plants, although C. nasturtii could lay eggs on the weeds. When weeds and cauliflower plants were simultaneously exposed to C. nasturtii adults for egg laying (choice tests), 97.3% of the C. nasturtii larvae were found on the cauliflower plants 8 d after oviposition, 2.7% on Sinapis arvensis L., and none on the other five weed species tested. Our results suggest that cruciferous weeds can serve as alternative host plants of C. nasturtii but are less suitable than cauliflower. A method of detecting C. nasturtii on weeds and control of C. nasturtii through weed management are discussed. PMID:19253625

Chen, Mao; Shelton, Anthony M; Wang, Ping; Hoepting, Christy A; Kain, Wendy C; Brainard, Daniel C

2009-02-01

296

Herbicide-resistant crops: utilities and limitations for herbicide-resistant weed management.  

PubMed

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

Green, Jerry M; Owen, Micheal D K

2011-06-01

297

Biology, ecology and management of the invasive parthenium weed (Parthenium hysterophorus L.).  

PubMed

Parthenium weed (Parthenium hysterophorus L.) is one of the most aggressive invasive weeds, threatening natural ecosystems and agroecosystems in over 30 countries worldwide. Parthenium weed causes losses of crops and pastures, degrading the biodiversity of natural plant communities, causing human and animal health hazards and resulting in serious economic losses to people and their interests in many countries around the globe. Several of its biological and ecological attributes contribute towards its invasiveness. Various management approaches (namely cultural, mechanical, chemical and biological control) have been used to minimise losses caused by this weed, but most of these approaches are ineffective and uneconomical and/or have limitations. Although chemical control using herbicides and biological control utilising exotic insects and pathogens have been found to contribute to the management of the weed, the weed nevertheless remains a significant problem. An integrated management approach is proposed here for the effective management of parthenium weed on a sustainable basis. PMID:24430973

Adkins, Steve; Shabbir, Asad

2014-07-01

298

Developing weed-suppressive soils through improved soil quality management  

Microsoft Academic Search

Manipulating soil microbial communities using soil and crop management practices is a basic strategy in developing sustainable agricultural systems. Sustainable farming is based, in part, on the efficient management of soil microorganisms to improve soil quality. However, the identification of biological indicators of soil quality that can be used to predict weed suppression in soils has received little attention. We

Robert J Kremer; Jianmei Li

2003-01-01

299

Revegetation Guidelines for the Great Basin: Considering Invasive Weeds  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

300

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...

301

Intra-row mechanical weed control—possibilities and problems  

Microsoft Academic Search

For five years, graduate students of the Tillage Laboratory of Wageningen Agricultural University studied the effectiveness of intra-row weed control by brushes, tactile hoes and weeder harrows in combination with a drill planting system and paper pots. From the technical point of view, brushes and tactile hoes were effective, reducing the amount of herbicides needed to about 10% of the

J. K. Kouwenhoven

1997-01-01

302

Insecticides and arable weeds: effects on germination and seedling growth.  

PubMed

The decline of many arable weed species in Northern Europe has been attributed to the intensification of modern agriculture and in particular, increasing pesticide use. In this study, we examined the effect of two insecticides, dimethoate and deltamethrin, on the germination and seedling growth of six arable weed species. Although germination was unaffected by insecticide application, seedling growth of four species was decreased by exposure to deltamethrin (Capsella bursa-pastoris and Poa annua), dimethoate (Agrostemma githago), or by both insecticides together (Urtica urens). While increased herbicide use, seed cleaning, and changing sowing times may be of primary importance in explaining the reduction of northern Europe's arable weed flora, our results indicate that insecticide use may also be a contributory factor. Moreover, those species that exhibit apparent tolerance of the insecticides tested, particularly the grass Avena fatua, may benefit from continued insecticide use. The ability to tolerate these agrochemicals, in tandem with reduced herbivory and competition from plants, whose growth is reduced by insecticide application, is likely to confer a significant competitive advantage on insecticide-resistant weed species. PMID:16385742

Hanley, M E; Whiting, M D

2005-05-01

303

Remote sensing water observation for supporting Lake Victoria weed management  

Microsoft Academic Search

This paper aims to assess the suitability of remote sensing for enhancing the management of water body resources and for providing an inexpensive way to gather, on a wide area, weed infestation extent and optical parameter linked to the water body status. Remotely sensed satellite images and ancillary ground true data were used to produce land cover maps, trough classification

Rosa Maria Cavalli; Giovanni Laneve; Lorenzo Fusilli; Stefano Pignatti; Federico Santini

2009-01-01

304

Weed control and desiccation strategies in chickpea Executive Summary  

E-print Network

-till studies, soil-applied and postemergence metribuzin generally caused significant crop injury and tended in the no- till system from soil-applied metribuzin at 0.25-0.33 lb/A. Postemergence metribuzin in the no metribuzin, none of the herbicide treatments reduced chickpea yield. At Minot, weed control varied by year

Lawrence, Rick L.

305

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...

306

Effects of Soybean Seed Size on Weed Competition  

Technology Transfer Automated Retrieval System (TEKTRAN)

Organic soybean producers must rely on various, nonherbicidal tactics for weed management. Increased soybean seed size may be one method to increase the competitiveness of the soybean canopy. Soybean varieties Hutcheson, NC-Roy, and NC-Raleigh were separated into four or five seed size classes. Seed...

307

Weed Community and Glyphosate Management in Soybean Crops  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

308

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...

309

Glyphosate resistant weeds - a threat to conservation agriculture  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

310

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...

311

A NOVEL BIOHERBICIDE FOR CONTROL OF GRASSY WEEDS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Pseudomonas spp. were isolated from the rhizosphere of Poa, Triticale, Triticum, Hordeum, and Lolium species. These bacterial isolates were initially screened for the ability of live cultures to cause stunting of the roots and shoots of young seedlings of the grassy weed known as annual bluegrass (...

312

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...

313

Weed Management with Diclosulam in Peanut (Arachis hypogaea) 1  

Microsoft Academic Search

Field experiments were conducted at three locations in North Carolina in 1998 and 1999 and one location in Virginia in 1998 to evaluate weed management systems in peanut. Treatments consisted of diclosulam alone preemergence (PRE), or diclosulam plus metolachlor PRE alone or followed by (fb) bentazon plus acifluorfen postemergence (POST). These systems were also com­ pared with commercial standards of

ANDREW J. PRICE; JOHN W. WILCUT; CHARLES W. SWANN

2002-01-01

314

Cover crop and organic weed control integration in tomato  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

315

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

SciTech Connect

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

Sledge, S.L.; Walker, R.H. [Auburn Univ., AL (United States)

1995-11-01

316

WEED SEEDLING EMERGENCE AND MICROCLIMATE IN A TROPICAL ENVIRONMENT  

Technology Transfer Automated Retrieval System (TEKTRAN)

Tropic ageratum (Ageratum conyzoides) is an important annual weed in tropical cropping systems. Better and more timely strategies for its control might be developed through a more thorough understanding of its emergence behavior. Seedling emergence of tropic ageratum was monitored periodically and s...

317

Weed control and canopy light management in blackberries  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

318

Real-time weed detection in outdoor field conditions  

NASA Astrophysics Data System (ADS)

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

Steward, Brian L.; Tian, Lei F.

1999-01-01

319

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

320

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

321

Corn gluten meal application equipment evaluations for organic weed control  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

322

Interannual variation in weed biomass on arable land in Sweden  

E-print Network

Interannual variation in weed biomass on arable land in Sweden P MILBERG, E HALLGREN* & M W PALMER Department of Biology-IFM, LinkoĂ?ping University, S-581 83 LinkoĂ?ping, Sweden, *Department of Ecology and Crop Production Science, SLU, Box 7043, S-750 07 Uppsala, Sweden, and Department of Botany, Oklahoma

Palmer, Michael W.

323

An application of soft sets in weed identification  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

324

ALLELOPATHIC EFFECTS OF DOPA AGAINST FOUR WEED SPECIES  

Microsoft Academic Search

Dopa is a natural product of some plants such as velvetbean. Its herbicidal effects on weed species; wild mustard (Sinapis arvensis), creeping thistle (Cirsium arvense), field poppy (Papaver rhoeas) and henbit (Lamium amplexicaule) were investigated using wheat (Triticum vulgare) and barley (Hordeum vulgare) species as control plants. Dopa showed suppressive herbicidal effect at 1500 and 3000 mg\\/l concentrations on the

Süleyman TOPAL

325

Robust crop and weed segmentation under uncontrolled outdoor illumination  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

326

Cuscuta Jepsonii (Convolvulaceae): An Invasive Weed or an Extinct Endemic?  

Microsoft Academic Search

Despite their ecological significance, parasitic plants face more conservation challenges than do autotrophic plants. This is especially true for the groups that include weedy or invasive species such as Cuscuta. While approximately half of the Cuscuta (dodders) species may require conservation measures, the genus as a whole is sometimes posted on governmental lists of noxious or quarantine weeds. Our study

Mihai Costea; Saša Stefanovi?

2009-01-01

327

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 ...

328

Weed Busters: How to Sweep Out Perennial Broomweed  

E-print Network

. L-5471 9/05 How to Sweep Out Perennial Broomweed Safe and effective three-step ways to control perennial broomweed Weed Treatment Series Charles R. Hart, Allan McGinty and J.F. Cadenhead Extension Range Specialists The Texas A&M University System...

Hart, Charles R.; McGinty, Allan; Cadenhead, J. F.

2005-10-05

329

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 ...

330

Weed Management Practice Selection Among Midwest U.S. Organic Growers James J. DeDecker, John B. Masiunas, Adam S. Davis, and Courtney G. Flint*  

E-print Network

implications of weeds and weed management in cropping systems, but adoption is minimal. Organic agriculture management. Clusters were distinguished by perspective regarding weeds and the number of weed management into the U.S. organic pest management standard through empha- sis on weed prevention, recognition of multiple

Williams, Martin M. II

331

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

PubMed

There is interest in more diverse weed management tactics because of evolved herbicide resistance in important weeds in many US and Canadian crop systems. While herbicide resistance in weeds is not new, the issue has become critical because of the adoption of simple, convenient and inexpensive crop systems based on genetically engineered glyphosate-tolerant crop cultivars. Importantly, genetic engineering has not been a factor in rice and wheat, two globally important food crops. There are many tactics that help to mitigate herbicide resistance in weeds and should be widely adopted. Evolved herbicide resistance in key weeds has influenced a limited number of growers to include a more diverse suite of tactics to supplement existing herbicidal tactics. Most growers still emphasize herbicides, often to the exclusion of alternative tactics. Application of integrated pest management for weeds is better characterized as integrated weed management, and more typically integrated herbicide management. However, adoption of diverse weed management tactics is limited. Modifying herbicide use will not solve herbicide resistance in weeds, and the relief provided by different herbicide use practices is generally short-lived at best. More diversity of tactics for weed management must be incorporated in crop systems. © 2014 Society of Chemical Industry. PMID:25346235

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

2014-10-27

332

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

PubMed Central

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

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

2014-01-01

333

Impact of the timing and duration of weed control on the establishment of a rubber tree plantation.  

PubMed

Rubber tree production is reduced by weeds that compete for environmental resources; therefore, the timing and duration of weed control influences weed interference. The objectives of this study were to evaluate the growth of rubber tree (Hevea brasiliensis) plants, to determine the critical period for weed control, and to evaluate the growth recovery of rubber trees that coexisted with weeds for different periods of time after planting. Two groups of treatments were established under field conditions in the first year of the investigation: one group contained crescent periods of weed infestation, while the other contained crescent periods of weed control, also including a weed-free check and a total weedy check. In the second year of the investigation, the weeds were totally controlled. Urochloa decumbens was the dominant weed (over 90% groundcover). Crop growth was greatly reduced due to the weed interference. Plant height decreased more rapidly than did any other characteristic. Plant height, leaf dry mass, and leaf area decreased by 99%, 97% and 96%, respectively, and were the most reduced characteristics. Plant height also recovered more rapidly than did any characteristic when the period of weed control was lengthened. However, stem dry mass increased by 750%, making it the most recovered characteristic. The critical period for weed control was between 4 and 9˝ months after planting in the first year; however, the rubber trees showed an expressive growth recovery when the weeds were controlled throughout the second year. PMID:24519007

Guzzo, Caio D; Carvalho, Leonardo B de; Giancotti, Paulo R F; Alves, Pedro L C A; Gonçalves, Elaine C P; Martins, José V F

2014-03-01

334

7 CFR 360.303 - Approval of an application for a permit to move a noxious weed; conditions specified in permit.  

Code of Federal Regulations, 2014 CFR

...application for a permit to move a noxious weed; conditions specified in permit. 360...SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.303 Approval of an application for a permit to move a noxious weed; conditions specified in permit....

2014-01-01

335

7 CFR 360.303 - Approval of an application for a permit to move a noxious weed; conditions specified in permit.  

Code of Federal Regulations, 2011 CFR

...application for a permit to move a noxious weed; conditions specified in permit. 360...SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.303 Approval of an application for a permit to move a noxious weed; conditions specified in permit....

2011-01-01

336

7 CFR 360.303 - Approval of an application for a permit to move a noxious weed; conditions specified in permit.  

Code of Federal Regulations, 2012 CFR

...application for a permit to move a noxious weed; conditions specified in permit. 360...SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.303 Approval of an application for a permit to move a noxious weed; conditions specified in permit....

2012-01-01

337

7 CFR 360.303 - Approval of an application for a permit to move a noxious weed; conditions specified in permit.  

Code of Federal Regulations, 2013 CFR

...application for a permit to move a noxious weed; conditions specified in permit. 360...SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.303 Approval of an application for a permit to move a noxious weed; conditions specified in permit....

2013-01-01

338

Allergens of weed pollen: an overview on recombinant and natural molecules.  

PubMed

Weeds represent a botanically unrelated group of plants that usually lack commercial or aesthetical value. Pollen of allergenic weeds are able to trigger type I reactions in allergic patients and can be found in the plant families of Asteraceae, Amaranthaceae, Plantaginaceae, Urticaceae, and Euphorbiaceae. To date, 34 weed pollen allergens are listed in the IUIS allergen nomenclature database, which were physicochemically and immunologically characterized to varying degrees. Relevant allergens of weeds belong to the pectate lyase family, defensin-like family, Ole e 1-like family, non-specific lipid transfer protein 1 family and the pan-allergens profilin and polcalcins. This review provides an overview on weed pollen allergens primarily focusing on the molecular level. In particular, the characteristics and properties of purified recombinant allergens and hypoallergenic derivatives are described and their potential use in diagnosis and therapy of weed pollen allergy is discussed. PMID:23806644

Gadermaier, Gabriele; Hauser, Michael; Ferreira, Fatima

2014-03-01

339

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. PMID:20596296

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

2010-01-01

340

G89-905 Weed Control on CRP Acres (Revised July 1997)  

Microsoft Academic Search

Establishing perennial grasses on former cropland presents a challenge. Weed control can be accomplished with herbicides, tillage, burning, mowing, and crop competition. The key to weed control is timeliness.\\u000aWeeds should be controlled on CRP acres to reduce the risk of seeding failure and eliminate possible reseeding costs. Soil moisture must be available for seed germination, seedling emergence, and establishment

Robert N. Klein; Gail A. Wicks; John E. Watkins; Jerry D. Volesky

1989-01-01

341

G99-1389 Cultural Practices to Improve Weed Control in Winter Wheat  

Microsoft Academic Search

This NebGuide explains the influence of cultural practices on weeds in winter wheat.\\u000aPrecipitation and temperature greatly influence crop and weed growth in the semiarid areas of the central Great Plains. Precipitation in Nebraska varies from 14 to 24 inches where fallow is practiced. The purpose of fallow is to control weeds and, when not cropping a field, to store

Gail A. Wicks; Alex Martin; Drew J. Lyon

1999-01-01

342

Weed Community Composition in Tree Fruit Nurseries Treated with Methyl Bromide and Alternative Fumigants  

Microsoft Academic Search

Many agricultural cropping systems have relied on methyl bromide (MeBr) for pest control, including weeds, for decades. Alternative fumigants are being sought worldwide because MeBr has been identified as an ozone-layer depleting substance. Weed communities respond dynamically to alterations in management systems. Thus, transition from MeBr to alternative fumigants may cause shifts in weed communities. This hypothesis was tested in

Anil Shrestha; Greg T. Browne; Bruce D. Lampinen; Sally M. Schneider; Thomas J. Trout

2009-01-01

343

Combining effect of allelopathic Sorghum bicolor L. (Moench) cultivars with planting densities on companion weeds  

Microsoft Academic Search

Field experiments were conducted to compare the effects of allelopathic sorghum cultivars ‘Enkath’ and ‘Rabeh’ at three planting densities (6.6, 13.3 and 26.6 plant m) on weed growth and sorghum yields in 2009 and 2010. Sorghum planting densities suppressed average weed population by 26–42% and average weed biomass by 46–57% compared with weedy check in 2009. A similar trend in

Nabil R. Al-Bedairy; Ibrahim S. Alsaadawi; Resan K. Shati

2012-01-01

344

Taxonomic and Life History Bias in Herbicide Resistant Weeds: Implications for Deployment of Resistant Crops  

PubMed Central

Evolved herbicide resistance (EHR) is an important agronomic problem and consequently a food security problem, as it jeopardizes herbicide effectiveness and increases the difficulty and cost of weed management. EHR in weeds was first reported in 1970 and the number of cases has accelerated dramatically over the last two decades. Despite 40 years of research on EHR, why some weeds evolve resistance and others do not is poorly understood. Here we ask whether weed species that have EHR are different from weeds in general. Comparing taxonomic and life history traits of weeds with EHR to a control group (“the world's worst weeds”), we found weeds with EHR significantly over-represented in certain plant families and having certain life history biases. In particular, resistance is overrepresented in Amaranthaceae, Brassicaceae and Poaceae relative to all weeds, and annuality is ca. 1.5 times as frequent in weeds with EHR as in the control group. Also, for perennial EHR weeds, vegetative reproduction is only 60% as frequent as in the control group. We found the same trends for subsets of weeds with EHR to acetolactate synthase (ALS), photosystem II (PSII), and 5-enolpyruvylshikimate-3-phosphate (EPSP) synthase-inhibitor herbicides and with multiple resistance. As herbicide resistant crops (transgenic or not) are increasingly deployed in developing countries, the problems of EHR could increase in those countries as it has in the USA if the selecting herbicides are heavily applied and appropriate management strategies are not employed. Given our analysis, we make some predictions about additional species that might evolve resistance. PMID:24039727

Holt, Jodie S.; Welles, Shana R.; Silvera, Katia; Heap, Ian M.; Heredia, Sylvia M.; Martinez-Berdeja, Alejandra; Palenscar, Kai T.; Sweet, Lynn C.; Ellstrand, Norman C.

2013-01-01

345

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

346

Weed hosts of Verticillium dahliae in crete: Susceptibility, symptomatology and significance  

Microsoft Academic Search

A survey of common and uncommon weed species usually showing Verticillium wilt symptoms was carried out during 1992–2000 in\\u000a Crete, Greece.Verticillium dahliae was isolated in 48 out of 182 sampled fields, in which several weed species were grown, from several locations in Oropedio,\\u000a Lasithi. Altogether, 124 isolates ofV. dahliae were recovered from the vascular stem-tissue of 19 weed species, belonging

E. K. Ligoxigakis; D. J. Vakalounakis; C. C. Thanassoulopoulos

2002-01-01

347

Cropping systems alter weed seed banks in Pacific Northwest semi-arid wheat region  

Microsoft Academic Search

Arable land weed seed banks are dynamic and reflect cropping history, current management, and environment. Changes in crop rotation and tillage system can alter weed seed density and species composition. In the semi-arid region of the Pacific Northwest, USA, no-till spring cropping is being studied as an alternative to the traditional winter wheat (Triticum aestivum L.)\\/dust-mulch fallow (WWF) rotation. Weed

F. L. Youngb

348

Cropping systems alter weed seed banks in Pacific Northwest semi-arid wheat region  

Microsoft Academic Search

Arable land weed seed banks are dynamic and reflect cropping history, current management, and environment. Changes in crop rotation and tillage system can alter weed seed density and species composition. In the semi-arid region of the Pacific Northwest, USA, no-till spring cropping is being studied as an alternative to the traditional winter wheat (Triticum aestivum L.)\\/dust-mulch fallow (WWF) rotation. Weed

M. E. Thorne; F. L. Young; J. P. Yenish

2007-01-01

349

WEED COMMUNITIES OF SUNFLOWER CROP IN SUKKUR AND KHAIRPUR, SINDH: AUTUMN ASPECT  

Microsoft Academic Search

The survey of weed communities of sunflower crop was conducted in five sunflower growing areas of Sukkur and Khairpur districts during 2003. A total of 33 weed species belonging to 30 genera and 15 angiosperm families were recorded. Five weed communities viz.: 1) Cyperus-Eclipta-Brachiaria in Ghulam Qasim Jiskani (district Khairpur), 2) Dactyloctenium-Cyperus- Brachiaria in Kotedji (district Khairpur), 3) Trianthema- Cyperus-Brachiaria

Rahmatullah Qureshi; Rabia Asma Memon

350

Effects of alternative winter cover cropping systems on weed suppression in organically grown tomato ( Solanum lycopersicum )  

Microsoft Academic Search

Weed control is a major concern for organic farmers around the world and non-chemical weed control methods are now the subject\\u000a of many investigations. Field studies were conducted in tomato (Solanum lycopersicum L.) from 2004 to 2006 at the Black Sea Agricultural Research Institute experiment field to determine the weed suppressive\\u000a effects of winter cover crops. Treatments consisted of ryegrass

Husrev Mennan; Mathieu Ngouajio; Dogan Is?k; Emine Kaya

2009-01-01

351

Differential tolerances of weed species to aluminum, manganese and salinity  

Microsoft Academic Search

Seven weed species were screened for tolerance to acid soil factors (Al and Mn toxicities) and to saline soil factors (NaCl and Na2SO4) in greenhouse peat cultures. Species used were: Echinochloa crusgalli (L.) Beauv. var. crusgalli?barnyard grass; Kochia scoparia (L.) Schrad.?Kochia?summer cypress; Setaria viridis (L.) Beauv.?green foxtail; Amaranthus retroflexus (L.) ? redroot pigweed; Chenopodium album (L.) ?lambsquarters; Convolvulus arvensis (L.)

J. J. Bilski; C. D. Foy

1988-01-01

352

Attachment of the parasitic weed dodder to the host  

Microsoft Academic Search

Summary.  ?The parasitic weed dodder (Cuscuta pentagona L.) invades a number of potential host species, but the mechanisms responsible for ensuring tight adhesion to the wide variety\\u000a of host surfaces have yet to be identified. In this study, a battery of microscopy protocols is used to examine the host–parasite\\u000a interface in an effort to deduce these mechanisms. As the dodder shoot

K. C. Vaughn

2002-01-01

353

Chemical weed control in Bulgarian coriander (Coriandrum sativum L.)  

Microsoft Academic Search

Field investigations carried out in two winter seasons of 1984–85 and 1985–86 on clay?loam soil at the Central Institute of Medicinal and Aromatic Plants, Regional Centre, Pantnagar, Naintial, India revealed that unrestricted weed growth reduced the seed and oil yields of Bulgarian coriander (Coriandrum sativum L. cv. S 33) by 40.3 and 37.0%, respectively. Applications of pendimethalin and fluchloralin at

S. K. Kothari; J. P. Singh; Kamla Singh

1989-01-01

354

Weed flora of cereal crops in Canterbury, New Zealand  

Microsoft Academic Search

Weed communities in Canterbury, New Zealand, cereal crops were characterised in the 1990–91, 1991–92, and 1992–93 growing seasons by measuring species population densities and harvest?time biomass in 39 and 45 fields respectively of wheat (Triticum aestivum) and barley (Hordeum vulgare) in the absence of herbicide treatments. A total of >57 species in >49 genera were recorded representing a total of

G. W. Bourdöt; G. A. Hurrell; D. J. Saville

1998-01-01

355

The viscous mucilage from the weed Portulaca oleracea, L  

Microsoft Academic Search

A polysaccharide complex has been extracted from the invasive and widespread weedPortulaca oleracea (purslane) in yields of up to 25 g% (dry wt). The clear and viscous mucilage displays physicochemical properties appropriate\\u000a for industrial uses, such as food extenders and viscosifier. Toxic collateral effects can be precluded because of the already\\u000a known uses in home remedies and animal feed. Anion

Guido E. Wenzel; J. D. Fontana; Joao B. C. Correa

1990-01-01

356

Potential for phytoextraction of PCBs from contaminated soils using weeds  

Microsoft Academic Search

A comprehensive investigation of the potential of twenty-seven different species of weeds to phytoextract polychlorinated biphenyls (PCBs) from contaminated soil was conducted at two field sites (Etobicoke and Lindsay) in southern Ontario, Canada. Soil concentrations were 31?g\\/g and 4.7?g\\/g at each site respectively. All species accumulated PCBs in their root and shoot tissues. Mean shoot concentrations at the two sites

Sarah A. Ficko; Allison Rutter; Barbara A. Zeeb

2010-01-01

357

Weed Control in Rainfed Cotton in Northern Ghana  

Microsoft Academic Search

In field experiments conducted at the Nyankpala Agricultural Station, Ghana, during 1976–77, soil moisture conditions appeared to be the deciding factor in determining the frequency of handweeding needed to obtain maximum seed cotton yields. In 1976, when planting was early and the late, heavy rains in October prolonged weed growth, two handweedings at 4 and 8 weeks after seeding (w.a.s.)

A. G. Carson

1979-01-01

358

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. PMID:24039714

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

2013-01-01

359

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.

360

Noxious Weed Monitoring at the US Air Force Academy-Year 2 Results  

E-print Network

Noxious Weed Monitoring at the US Air Force Academy- Year 2 Results June 26, 2007 Prepared For: U.......................................................................... 7 RESULTS........................................................................ 10 OTHER RESULTS

361

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

PubMed Central

Weeds can cause great economic and ecological harm to ecosystems. Despite their importance, comparisons of the taxonomy and traits of successful weeds often focus on a few specific comparisons – for example, introduced versus native weeds.We used publicly available inventories of US plant species to make comprehensive comparisons of the factors that underlie weediness. We quantitatively examined taxonomy to determine if certain genera are overrepresented by introduced, weedy or herbicide-resistant species, and we compared phenotypic traits of weeds to those of nonweeds, whether introduced or native.We uncovered genera that have more weeds and introduced species than expected by chance and plant families that have more herbicide-resistant species than expected by chance. Certain traits, generally related to fast reproduction, were more likely to be associated with weedy plants regardless of species’ origins. We also found stress tolerance traits associated with either native or introduced weeds compared with native or introduced nonweeds. Weeds and introduced species have significantly smaller genomes than nonweeds and native species.These results support trends for weedy plants reported from other floras, suggest that native and introduced weeds have different stress adaptations, and provide a comprehensive survey of trends across weeds within the USA. PMID:24494694

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

2014-01-01

362

Integration of Agronomic Practices with Herbicides for Sustainable Weed Management in Aerobic Rice  

PubMed Central

Till now, herbicide seems to be a cost effective tool from an agronomic view point to control weeds. But long term efficacy and sustainability issues are the driving forces behind the reconsideration of herbicide dependent weed management strategy in rice. This demands reappearance of physical and cultural management options combined with judicious herbicide application in a more comprehensive and integrated way. Keeping those in mind, some agronomic tools along with different manual weeding and herbicides combinations were evaluated for their weed control efficacy in rice under aerobic soil conditions. Combination of competitive variety, higher seeding rate, and seed priming resulted in more competitive cropping system in favor of rice, which was reflected in lower weed pressure, higher weed control efficiency, and better yield. Most of the herbicides exhibited excellent weed control efficiency. Treatments comprising only herbicides required less cost involvement but produced higher net benefit. On the contrary, treatments comprising both herbicide and manual weeding required high cost involvement and thus produced lower net benefit. Therefore, adoption of competitive rice variety, higher seed rate, and seed priming along with spraying different early-postemergence herbicides in rotation at 10 days after seeding (DAS) followed by a manual weeding at 30 DAS may be recommended from sustainability view point. PMID:24223513

Anwar, M. P.; Juraimi, A. S.; Mohamed, M. T. M.; Uddin, M. K.; Samedani, B.; Puteh, A.; Man, Azmi

2013-01-01

363

Broccoli/weed/soil discrimination by optical reflectance using neural networks  

NASA Astrophysics Data System (ADS)

Broccoli is grown extensively in Scotland, and has become one of the main vegetables cropped, due to its high yields and profits. Broccoli, weed and soil samples from 6 different farms were collected and their spectra obtained and analyzed using discriminant analysis. High crop/weed/soil discrimination success rates were encountered in each farm, but the selected wavelengths varied in each farm due to differences in broccoli variety, weed species incidence and soil type. In order to use only three wavelengths, neural networks were introduced and high crop/weed/soil discrimination accuracies for each farm were achieved.

Hahn, Federico

1995-04-01

364

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

E-print Network

??Weeds are the most costly of all agricultural pests, reducing crop yields, quality and harvestability while simultaneously increasing management expenses. Restriction of synthetic herbicide use… (more)

Dedecker, James

2012-01-01

365

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

366

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

NASA Astrophysics Data System (ADS)

Peppermint and spearmint are high value essential oil crops in Indiana, Michigan, and Wisconsin. Although the mints are profitable alternatives to corn and soybeans, mint production efficiency must improve in order to allow industry survival against foreign produced oils and synthetic flavorings. Weed control is the major input cost in mint production and tools to increase efficiency are necessary. Remote sensing-based site-specific weed management offers potential for decreasing weed control costs through simplified weed detection and control from accurate site specific weed and herbicide application maps. This research showed the practicability of remote sensing for weed detection in the mints. Research was designed to compare spectral response curves of field grown mint and weeds, and to use these data to develop spectral vegetation indices for automated weed detection. Viability of remote sensing in mint production was established using unsupervised classification, supervised classification, handheld spectroradiometer readings and spectral vegetation indices (SVIs). Unsupervised classification of multispectral images of peppermint production fields generated crop health maps with 92 and 67% accuracy in meadow and row peppermint, respectively. Supervised classification of multispectral images identified weed infestations with 97% and 85% accuracy for meadow and row peppermint, respectively. Supervised classification showed that peppermint was spectrally distinct from weeds, but the accuracy of these measures was dependent on extensive ground referencing which is impractical and too costly for on-farm use. Handheld spectroradiometer measurements of peppermint, spearmint, and several weeds and crop and weed mixtures were taken over three years from greenhouse grown plants, replicated field plots, and production peppermint and spearmint fields. Results showed that mints have greater near infrared (NIR) and lower green reflectance and a steeper red edge slope than all weed species. These distinguishing characteristics were combined to develop narrow band and broadband spectral vegetation indices (SVIs, ratios of NIR/green reflectance), that were effective in differentiating mint from key weed species. Hyperspectral images of production peppermint and spearmint fields were then classified using SVI-based classification. Narrowband and broadband SVIs classified early season peppermint and spearmint with 64 to 100% accuracy compared to 79 to 100% accuracy for supervised classification of multispectral images of the same fields. Broadband SVIs have potential for use as an automated spectral indicator for weeds in the mints since they require minimal ground referencing and can be calculated from multispectral imagery which is cheaper and more readily available than hyperspectral imagery. This research will allow growers to implement remote sensing based site specific weed management in mint resulting in reduced grower input costs and reduced herbicide entry into the environment and will have applications in other specialty and meadow crops.

Gumz, Mary Saumur Paulson

367

National Evaluation of Weed & Seed: Cross-Site Analysis  

NSDL National Science Digital Library

Published this month by the Department of Justice, this report assesses the results of the "weed and seed" approach to crime prevention, monitored for the last eight years at eight selected area sites in the U.S.. "Weeding" is defined as "concentrated and enhanced law enforcement efforts to identify, arrest, and prosecute" criminals, especially violent offenders and drug traffickers. The cited objective is the removal of criminals from the targeted area. "Seeding" involves community efforts to deter further crime by offering a variety of human services, including afterschool, weekend, and summer youth activities; adult literacy classes; parental counseling; and neighborhood revitalization. The report offers cross-site analysis and finds that the most effective results were achieved in sites of smaller geographical area with more community resources to bring to bear. The report concludes that "in selecting sites for new program funding, Weed and Seed should place its funding priority on sites with geographically small target areas and with favorable community settings and program designs."

Cordner, Gary.

368

Experimental and natural weed host-virus relations.  

PubMed

Weeds, as alternative hosts of plant viruses and nutrient plants of virus vectors play important role in virus ecology and epidemiology. The aim of our study was to discover new weed-virus relations. Therefore some weed species were mechanically inoculated with 28 viruses (strains or isolates) maintained in our glasshouse. Different weed species with and without visible symptoms were collected from agro-, water ecosystems and wastelands of Hungary between 1997 and 2003. Virus infections were evaluated by biotests, DAS ELISA serological methods, electronmicroscopy and immunosorbent electronmicroscopy (ISEM). Under glasshouse conditions Ambrosia artemisifolia was considered as a virophob species, showing resistance to all viruses listed above. A series of new artificial (Chenopodium album--SoMV (LH+SH)*, AMV (LH+SH); C. berlandieri--PVY(NTN) (LH), AMV (LH+SH), CMV (LH), SoMV (LH+SH), ObPV (LH+SH), ZYMV-10 (LH): C. ugandae--ObPV (LH), SoMV (L); C. glaucum--ObPV (LH), SoMV (L); Echinocystis lobata--PVX (L), ZYMV (LH+SH); Solanum nigrum--MYFV (LH+SH), PVY(N) (L), PVY(NTN) (LH+SH), SoMV (LH), TMV (SH), CMV (SH); S. dulcamara--CMV-U/246 (SH), PVY(NTN) (LH), SoMV-H (L), TMV-O (L); S. luteum--PVY(N) (SH), PVY(NTN) (LH+L), TMV(SH).) and natural (Asclepias syriaca--TMV, AMV, TSWV; Alisma plantago-aquatica--PVY, SoMV; Ambrosia artemisiifolia--CMV; Chenopodium album--CMV, PVS, PLRV; C. hybridum--CMV; Cirsium canum--CMV, PVM; Carex vulpina--CMV; Comium maculatum--PVY; Datura stramonium--PVA, PVX, PVS, PVM, CMV, TMV; Lysimachia vulgaris--ArMV, BNYVV, CMV, TMV; Lythrum salicaria--ArMV; Malva neglecta--CMV; Mercurialis annua--SoMV; Solanum nigrum--CMV, PVY, PVY(N); Solidago gigantea--CMV, RpRSV, BNYVV; Stenactis annua--PVM, PVA) weed--virus relations were detected. The epidemiological role of perennial hosts (A. syriaca, A. planlago aquatica, C. canurm, L. vulgaris, L. salicaria, S. gigantea) is especially high, because they can serve as infection sources as well as overwintering hosts of different plant viruses. PMID:15759395

Kazinczi, G; Horváth, J; Takács, A P; Gáborjányi, R; Béres, I

2004-01-01

369

Laboratory Food Choice Trials to Explore the Potential of Common Weeds to Reduce Slug Feeding on Oilseed Rape  

Microsoft Academic Search

Food choice trials with the slug pests Arion lusitanicus and Deroceras reticulatum were carried out in the laboratory, using seedlings of rape, Brassica napus and several weed species. The attraction of the weeds to the slugs was compared with rape and, subsequently, the potential of the presence of weeds to reduce slug feeding on young rape was assessed. Capsella bursa-pastoris

T. Frank; J. Friedli

1999-01-01

370

Modeling with Limited Data: The Influence of Crop Rotation and Management on Weed Communities and Crop Yield Loss  

Technology Transfer Automated Retrieval System (TEKTRAN)

Theory and models of crop yield loss from weed competition have lead to decision models to help growers with cost-effective tactical weed management. Weed management decision models are available for multiple-species populations in a single season of several crops. Growers also rely on crop rotation...

371

75 FR 57496 - Notice of Proposed Supplementary Rule To Require the Use of Certified Noxious-Weed-Free Forage...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Require the Use of Certified Noxious-Weed-Free Forage and Straw on Bureau of Land...lands in Idaho to use certified noxious-weed-free forage and straw. Restoration...stabilization projects also will be required to use weed-free straw bales and mulch for...

2010-09-21

372

Krueger-Mangold et al.: Ecologically-based invasive plant management 597 Weed Science, 54:597605. 2006  

E-print Network

the weeds with traditional control methods, such as herbicides, biocontrols, or mechanical control may temporarily control the weeds but may ultimately have minimal influence on ecological processesKrueger-Mangold et al.: Ecologically-based invasive plant management · 597 Weed Science, 54

Brown, Cynthia S.

373

Weed Management in Pastures and Rangeland -20091 B.A. Sellers and J.A. Ferrell2  

E-print Network

, mechanical or chemical methods are usually employed to control the weeds (Table 1). However, unless the basic the area. Mechanical Control Mowing is one of the most often used methods of weed control in pastures of County Commissioners Cooperating. Interim Dean Millie Ferrer. Effective weed control begins with good

Jawitz, James W.

374

Plant Pathogens at Work: Progress and Possibilities for Weed Biocontrol Part 1. Classical versus Bioherbicidal Approach  

Technology Transfer Automated Retrieval System (TEKTRAN)

Weeds are a perpetual problem for agriculture, causing significant reductions in the quantity and quality of crop yields. Weeds also incur extra costs related to harvesting and increase production costs through the need for mechanical, chemical, and biological inputs for their management. Based on ...

375

Characteristics of Herbicides and Weed Management Programs Most Important to Corn, Cotton, and Soybean Growers  

E-print Network

Characteristics of Herbicides and Weed Management Programs Most Important to Corn, Cotton of Herbicides and Weed Management Programs Most Important to Corn, Cotton, and Soybean Growers T.M. Hurley characteristics that influence profitability, using data from a telephone survey of 1,205 corn, cotton

Mitchell, Paul D.

376

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

377

Technology Transfer Programs for Biological Control of Weeds — the New Zealand Experience  

Microsoft Academic Search

Biological control has become a major focus for managing a variety of agricultural and conservation weeds in New Zealand. For nearly 2 decades Landcare Research (for- merly DSIR) has operated successful technology transfer programs with most organiza- tions that manage weeds in New Zealand. Program success is based on strong relation- ships built up between Landcare Research and participating organizations

L. M. HAYES

378

Comparative analysis for germination and seedling growth of wheat with some competitive weeds under salinity  

Microsoft Academic Search

Wheat (Triticum aestivum L.) is one of the most important cereals in Turkey. Besides many biotic and abiotic factors weeds compete for available nitrogen and light which ultimately affects grain yield, increase harvest, storage, transportation cost and grain quality. The objective of the research was to compare wheat and wheat competitive weeds for germination, emergence and seedling growth under saline

Gamze Kay; Mehmet Demir Kay; Yusuf Arslan

2009-01-01

379

A susceptible weed host can compromise suppression of Meloidogyne incognita by resistant cotton  

Technology Transfer Automated Retrieval System (TEKTRAN)

Weeds can support nematode reproduction when a non-host or resistant host crop is grown. Meloidogyne incognita, the dominant nematode pathogen of cotton in many areas in the US, reproduces well on prickly sida (Sida spinosa), which is a significant weed in some cotton-producing areas. The developm...

380

Weed suppressive rice for drill-seeded systems of the Southern USA: Research strategies and limitations  

Technology Transfer Automated Retrieval System (TEKTRAN)

Effective, affordable weed control is a challenge to sustainable rice production in the U.S. Research efforts in Arkansas have identified several rice lines that can suppress economically important C4 grass weeds such as Echinochloa crus-galli and Leptochloa fusca ssp. fascicularis. Earlier findin...

381

The evolutionary history of an invasive species: alligator weed, Alternanthera philoxeroides  

Technology Transfer Automated Retrieval System (TEKTRAN)

The eco-evolutionary mechanisms of biological invasions are still not thoroughly understood. Alligator weed, Alternanthera philoxeroides (Martius) Gisebach (Amaranthaceae), is a plant native to South America and a weed in Australia and other countries. To better understand its success as an invader,...

382

Weed Control Strategies for Organic Peanut Production and Transition: A Lesson in Basic Agronomy  

Technology Transfer Automated Retrieval System (TEKTRAN)

Weed control in organic peanut production is difficult and costly. The only production inputs that consistently improved weed management in organic peanut production were modified production practices and intense cultivation with a tine weeder. Research trials evaluated row patterns, seeding rates...

383

Software to quantify and map vegetative cover in fallow fields for weed management decisions  

Technology Transfer Automated Retrieval System (TEKTRAN)

Mapping weed cover during the fallow period of dryland crop rotations would be valuable for weed management in subsequent crops and could be done with low cost color digital cameras, however most managers lack the specialized software and expertise needed to create a map from the images. We develope...

384

Impact of broadcast applications of acetic acid on onion injury and weed control  

Technology Transfer Automated Retrieval System (TEKTRAN)

Interest in organic onion production is growing throughout the areas now producing onions with conventional methods, but weed control continues to be a primary obstacle. Weed control is ranked as the number one research priority by organic vegetable producers. The few organic herbicides cleared for ...

385

Integrated approaches to managing weeds in spring-sown crops in western Canada  

Microsoft Academic Search

In western Canada, the move to integrated weed management (IWM) with reduced dependence on herbicides is being driven by low crop prices, weed resistance to herbicides, and environmental concerns. A rational step when implementing IWM is to determine if herbicide application is required in the first place. Crop yield loss models have been developed to assist with this decision. However,

J. T. O’Donovan; R. E. Blackshaw; K. N. Harker; G. W. Clayton; J. R. Moyer; L. M. Dosdall; D. C. Maurice; T. K. Turkington

2007-01-01

386

Broadcast application of Matran for broadleaf weed control in spring-transplanted onions  

Technology Transfer Automated Retrieval System (TEKTRAN)

Weed competition can cause serious yield reductions if not controlled throughout the growing season. Corn gluten meal can provide early season control, but additional organic herbicides need to be evaluated for mid to late season weed control. Research was conducted in southeast Oklahoma to determ...

387

Grass Carp: A Fish for Biological Management of Hydrilla and Other Aquatic Weeds in Florida1  

E-print Network

BUL867 Grass Carp: A Fish for Biological Management of Hydrilla and Other Aquatic Weeds in Florida1 aquatic weed problems. This bulletin provides information on a biological method, the grass carp plants. Since the grass carp is a living organism, in contrast to ei- ther herbicides or mechanical

Watson, Craig A.

388

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...

389

PERENNIAL CROP NURSERIES TREATED WITH METHYL BROMIDE AND ALTERNATIVE FUMIGANTS: EFFECT ON WEED COMMUNITY COMPOSTION  

Technology Transfer Automated Retrieval System (TEKTRAN)

Weed communities can respond dynamically to shifts in management systems. Thus, transition from methyl bromide (MeBr) to alternative fumigants for pre-plant soil treatments may cause shifts in weed species composition. This hypothesis was tested in four perennial crop nurseries in California. The...

390

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 ...

391

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

Microsoft Academic Search

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

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

2007-01-01

392

Volunteer Potato Density Influences Critical Time of Weed Removal in Bulb Onion  

E-print Network

Volunteer Potato Density Influences Critical Time of Weed Removal in Bulb Onion Martin M. Williams II, Corey V. Ransom, and W. Mack Thompson* Volunteer potato is highly competitive with onion and few control tactics are effective for removing this weed from an onion crop. Both volunteer potato density

Sims, Gerald K.

393

WEED MANAGEMENT DECISION MODELS: PITFALLS, PERCEPTIONS, AND POSSIBILITIES OF THE ECONOMIC THRESHOLD APPROACH  

Technology Transfer Automated Retrieval System (TEKTRAN)

A World Wide Web survey was conducted to investigate perceptions of weed science professionals regarding the value of weed management decision models based on economic thresholds. Over half of the 56 respondents were involved in model development or support, and 82% thought decision models could be ...

394

Tine cultivation effects on weed control, productivity, and economics of peanut under organic management  

Technology Transfer Automated Retrieval System (TEKTRAN)

Identifying effective weed control regimes for organic peanut has become paramount for improving the feasibility of organic production. Tine cultivation is a proven effective method at reducing in-row weed populations in several crops. Field trials were therefore conducted in 2008 and 2009 to asse...

395

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...

396

NEW YORK WEED SCIENCE FIELD DAY -2013 JULY 17 -WEDNESDAY H. C. THOMPSON RESEARCH FARM  

E-print Network

NEW YORK WEED SCIENCE FIELD DAY - 2013 JULY 17 - WEDNESDAY ­ H. C. THOMPSON RESEARCH FARM Freeville a formal Weed Science Field Day at the H. C. Thompson Research Farm this year. If you want to see. MUSGRAVE RESEARCH FARM 1256 Poplar Ridge Road, Aurora, NY 13026 (Poplar Ridge Road, connects 90 and 34B) 11

Keinan, Alon

397

PRECISION FARMING TECHNOLOGIES FOR WEED CONTROL IN THE MISSISSIPPI DELTA MANAGEMENT SYSTEMS EVALUATION AREA  

Technology Transfer Automated Retrieval System (TEKTRAN)

Studies were conducted to evaluate two precision farming technologies for weed control in the Mississippi Delta Management systems Evaluation Area (MDMSEA). A sensor-controlled hooded sprayer that utilized spectral reflectance type sensors to detect and spray only where weeds were present was evalu...

398

Variable Seed Viability of Mile-a-Minute Weed (Devil's Tearthumb, Persicaria perfoliata)  

Technology Transfer Automated Retrieval System (TEKTRAN)

Mile-a-minute weed or devil's tearthumb is an invasive annual vine in the Mid-Atlantic and Northeastern United States. It reproduces solely through seeds, and therefore a key aspect of mile-a-minute weed biology and control concerns the production of viable seed. Our study aimed to identify how seed...

399

Briquetting soda weed ( Salsola tragus) to be used as a rural fuel source  

Microsoft Academic Search

Amount of traditional fuel sources in the world has been decreasing and there is a definite need to produce and utilize alternative fuels such as biomass materials. In this study, briquetting conditions of Russian tumbleweed, Salsola tragus, (commonly named soda weed in Turkey) which grows in salty soils were investigated.Soda weeds were first chopped coarsely in a local tresher, then

Hasan Yumak; Tamer Ucar; Nesim Seyidbekiroglu

2010-01-01

400

Broadcast application of vinegar for broadleaf weed control in spring-transplanted onions  

Technology Transfer Automated Retrieval System (TEKTRAN)

Vinegar (acetic acid) is a non-selective contact herbicide used in organic crop production. Research was conducted to determine if vinegar could be successfully applied over the top of onion plants to control broadleaf weeds. The experiment included 6 weed control treatments (2 application volumes...

401

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

Federal Register 2010, 2011, 2012, 2013, 2014

...Background The Plant Protection Act (PPA, 7 U.S.C. 7701 et seq.), authorizes...noxious weed within the United States. The PPA defines ``noxious weed'' as ``any...environment.'' Under the authority of the PPA, the Animal and Plant Health...

2011-07-07

402

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

403

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

404

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

405

Mathematical simulation of soil microclimate conditions for predicting weed seed germination  

Technology Transfer Automated Retrieval System (TEKTRAN)

Microclimate-based models for weed seed emergence are in the initial phases of development. The major driving forces of weed seed germination in the soil environment are temperature and soil moisture content. In the past these quantities have been measured at a single point (e.g., 5 cm). However, th...

406

WEED CONTROL IN FLUE-CURED TOBACCO Charles S. Johnson, Extension Plant Pathologist, Tobacco  

E-print Network

WEED CONTROL IN FLUE-CURED TOBACCO Charles S. Johnson, Extension Plant Pathologist, Tobacco Good herbicides in rotation crops may reduce populations of hard-to-control weeds in tobacco fields. The table-cured tobacco fields in Virginia. Soil Texture and Organic Matter Content - Herbicide rates should increase

Buehrer, R. Michael

407

Critical periods of weed interference in Japanese mint (Mentha arvensis L.)  

Microsoft Academic Search

Results from two sets of field experiments carried out during 1984 and 1985 revealed that Japanese mint (Mentha arvensis L.) was associated with both broad?leaf and grass weeds dominant in summer and rainy seasons representing the period of first and second harvests, respectively. The weed biomass exceeded that of the crop from the very beginning of the crop cycle, and

S. K. Kothari; D. V. Singh; K. Singh

1991-01-01

408

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

409

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...

410

Impact of Management on Weed Species Composition in Organically Cropped Spring Cereals  

Microsoft Academic Search

Partial Redundancy Analysis (pRDA) was applied to analyse the relationship between weed species composition and agricultural management measures in organically cropped spring cereal fields. Density and dry weight of weed species were assessed in 30 fields situated in the coastal regions of Finland. The pRDA analysis included nine explanatory variables describing management (years since conversion to organic farming, crop rotation,

P. Riesinger; T. Hyvönen

2006-01-01

411

Weed seed predation increases with vegetation cover in perennial forage crops  

Microsoft Academic Search

Vegetation cover may affect weed seed predation by modifying the habitat quality for predatory organisms. Post-dispersal weed seed predation was measured by placing ‘seed cards’ in two perennial crops (alfalfa, cocksfoot) with and without crop cutting and in plots with bare soil. Each treatment was repeated four times in a randomized complete block design. Vegetation cover was measured by canopy

Helmut Meiss; Lise Le Lagadec; Nicolas Munier-Jolain; Rainer Waldhardt; Sandrine Petit

2010-01-01

412

Weed species diversity and community composition in organic and conventional cropping of spring cereals  

Microsoft Academic Search

Interest in organic farming is growing rapidly in Europe. The resulting expansion of the organic farming area has been expected to enhance the biodiversity of agricultural habitats. Organic cropping practices can be hypothesized to support a higher number of weed species than conventional cropping and also to favor herbicide-susceptible and less-nitrophilous species. The diversity and species composition of weed communities

Terho Hyvönen; Elise Ketoja; Jukka Salonen; Heikki Jalli; Juha Tiainen

2003-01-01

413

Weed control and sweet maize (Zea mays L.) yield as affected by pyroxasulfone dose  

Microsoft Academic Search

Pyroxasulfone is a new herbicide being considered for registration in sweet maize in Canada; however, there is still little information on the doses required to provide 90% control of annual grass and broadleaved weeds found in southwestern Ontario. The objective of this study was to determine pyroxasulfone doses that would provide at least 90% control of several economically important weeds,

Robert E. Nurse; Peter H. Sikkema; Darren E. Robinson

2011-01-01

414

Suitability of organic mulch (distillation waste) and herbicides for weed management in perennial aromatic grasses  

Microsoft Academic Search

Poor economic return from perennial aromatic grasses during a planting year results from the high cost of cultivation, on account of planting, and lower yields, largely due to slow crop growth rate and high vulnerability of aromatic grasses to weeds, which are poorly managed In the absence of suitable weed control measures. Field experiments were established in July 1982 to

A. Singh; K. Singh; D. V. Singh

1991-01-01

415

Pelargonic acid for weed control in organic Vidalia sweet onion production  

Technology Transfer Automated Retrieval System (TEKTRAN)

Cultivation using a tine weeder is a proven means to manage weeds in organic Vidalia® sweet onion production. If the initial cultivation is delayed, emerged weeds are not controlled by the tine weeder. In these cases, herbicides derived from natural products could be used to control the emerged we...

416

Onion weed control with post-directed applications of pelargonic acid  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

417

Pelargonic acid formulations, application rates, and sequential applications for weed control in squash  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

418

Weed control in yellow squash using sequential postdirected applications of pelargonic acid  

Technology Transfer Automated Retrieval System (TEKTRAN)

Squash (Cucurbita pepo L.) producers would benefit from appropriate herbicides that can effectively provide season-long weed control. Research was conducted in southeast Oklahoma (Atoka County, Lane, OK) during 2010 and 2011 to determine the impact of a naturally derived herbicide on weed control ef...

419

Weed Control 2008 Burley ToBacco ProducTion Guide  

E-print Network

. Johnson, Extension Plant Pathologist, Tobacco Good weed control uses crop rotation, early root destruction: Coarse Soils - sands, loamy sands, and sandy loams; Me- dium Soils - sandy clay loams, loams, silt loams seed germination. Thoroughly work all weed growth and crop stubble into the soil prior to application

Liskiewicz, Maciej

420

The effect of competition from different weed species on the growth of Betula pendula seedlings  

Microsoft Academic Search

The identification of less competitive weed species and infestation rates might allow weeding operations to be better targeted, help conserve local plant biodiversity, and facilitate reductions in the amount of herbicide used to achieve woodland regeneration. Therefore, the effect of competition from pure stands of Cirsium vulgare (Savi) Ten., Epilobium ciliatum Raf., Holcus lanatus L., Poa annua L., and Persicaria

Ian Willoughby; David V. Clay; Fiona L. Dixon; Geoff W. Morgan

2006-01-01

421

Growth Suppression of Annual Weeds by Deleterious Rhizobacteria Integrated with Cover Crops  

Microsoft Academic Search

Development and rapid acceptance of biological control is challenged by factors lim- iting the spectrum of activity, efficacy, and reliability. Effectiveness of biological control may be best demonstrated as a component in an overall biological weed management sys- tem. Cover crops as components of biological weed management may be used for inte- grating biological control agents by promoting establishment in

R. J. KREMER

422

Effect of herbicides applied pre- and post-emergence on forestry weeds grown from seed  

Microsoft Academic Search

Weeds growing from seed can cause severe problems in forest nurseries and in woodland establishment by competing for resources with the young trees, leading to reduced growth and survival. Herbicides approved for use on new plantings of farm forestry and forest nurseries were usually developed originally for use in agricultural crops. As a result, information on the susceptibility of weeds

F. L. Dixon; D. V. Clay

2004-01-01

423

Exotic weed control treatments for conservation of fescue grassland in Montana  

Microsoft Academic Search

An analytical framework is described to evaluate exotic weed control treatments applied to native vegetation for conservation purposes. The analyses were used to assess the following responses to herbicide applications for control of an exotic forb Centaurea maculosa in fescue grassland: (1) efficacy on the target weed species, (2) similarity to reference stands defining the potential natural communities, (3) resistance

Peter M. Rice; J. Christopher Toney

1998-01-01

424

Molecular mechanisms responsive to dehydration may impact the invasiveness of perennial weeds under global climate change  

Technology Transfer Automated Retrieval System (TEKTRAN)

Leafy spurge is an invasive perennial weed in the great plains of the US and Canada. The ability of this herbaceous weed to regenerate new shoot growth from an abundance of crown and root buds after severe abiotic stress is critical for survival. Due to its adaptable and aggressive nature, global cl...

425

GIS Analysis of Spatial Clustering and Temporal Change in Weeds of Grass Seed Crops  

Technology Transfer Automated Retrieval System (TEKTRAN)

Ten years of Oregon Seed Certification Service pre-harvest field inspection reports previously converted from a non-spatial database to a GIS were used to analyze spatial patterns in distribution of severity of the 36 most commonly occurring weeds. Moran's I spatial autocorrelation of maximum weed ...

426

Invasive Weeds in Mexico: Overview of Awareness, Management and Legal Aspects  

Microsoft Academic Search

The status of the awareness, knowledge, management and societal involvement in invasive weeds in Mexico is reviewed. The invasive species awareness in Mexico is very limited, and it is concentrated mainly in a governmental commission and in a handful of university scientists. This is probably due to the relatively slow process in which exotic weeds become pests, gaining attention when

Francisco J. Espinosa-García

427

Weed occurrence in Finnish coastal regions: a survey of organically cropped spring cereals  

Microsoft Academic Search

Weed communities of organically cropped spring cereal stands in the southern and the northwestern coast- al regions of Finland (= south and northwest, respectively) were compared with respect to number of spe- cies, frequency of occurrence, density and dry weight. Regional specialization of agricultural production along with differences in climate and soil properties were expected to generate differences in weed

Paul Riesinger; Terho Hyvönen

2006-01-01

428

The biology of Canadian weeds. 117. Taraxacum officinale G. H. Weber ex Wiggers  

E-print Network

The biology of Canadian weeds. 117. Taraxacum officinale G. H. Weber ex Wiggers S. M. Stewart-Wade1 officinale G. H. Weber ex Wiggers. Can. J. Plant Sci. 82: 825­853. Taraxacum officinale G. H. Weber ex words: Taraxacum officinale, dandelion, weed biology, Canada. Stewart-Wade, S. M., Neumann, S., Collins

Boland, Greg J.

429

The social construction of weeds: different reactions to an emergent problem by farmers, officials and researchers  

Microsoft Academic Search

Rapid population increase in southern Benin has changed the prevailing system of shifting cultivation into one of more permanent land use. New herbaceous weeds exacerbated rural poverty through crop failure, higher labour inputs, rising costs of production and reduced availability of suitable land. We investigated how different actors reacted to the emergence of weeds, in terms of the construction of

P. V. Vissoh; R. Mongbo; G. Gbčhounou; D. Hounkonnou; A. Ahanchédé; N. G. Roling; T. W. Kuyper

2007-01-01

430

Applying molecular-based approaches to classical biological control of weeds John F. Gaskin a,  

E-print Network

Review Applying molecular-based approaches to classical biological control of weeds John F. Gaskin. This review provides an overview of how to use molecular approaches in biological control of weeds the biology and ecology of agents and their targets and those with skills using molecular approaches. We

Hufbauer, Ruth A.

431

PLANTING DATE INFLUENCES CRITICAL PERIOD OF WEED CONTROL IN SWEET CORN  

Technology Transfer Automated Retrieval System (TEKTRAN)

The critical period for weed control (CPWC) identifies the phase of the crop growth cycle when weed interference results in unacceptable yield losses; however, the effect of planting date on CPWC is poorly known. Field studies were conducted in 2004 and 2005 at Urbana, IL to determine CPWC in sweet...

432

The taxonomic distribution of invasive angiosperm plants: Ecological insights and comparison to agricultural weeds  

Microsoft Academic Search

Global data sets of serious agricultural weeds (1348 species), widespread agricultural weeds (1041 species), and threatening natural area invaders (381 species) were assembled, and taxonomic patterns among these data sets were compared to gain insights into how these groups differ ecologically. Angiosperm taxonomic groups (families, orders and subclasses) were tested for over- and under-representation using resampling tests, and ecological characteristics

Curtis C. Daehler

1998-01-01

433

Herbicides as weed control agents: state of the art: I. Weed control research and safener technology: the path to modern agriculture.  

PubMed

The purpose of modern industrial herbicides is to control weeds. The species of weeds that plague crops today are a consequence of the historical past, being related to the history of the evolution of crops and farming practices. Chemical weed control began over a century ago with inorganic compounds and transitioned to the age of organic herbicides. Targeted herbicide research has created a steady stream of successful products. However, safeners have proven to be more difficult to find. Once found, the mode of action of the safener must be determined, partly to help in the discovery of further compounds within the same class. However, mounting regulatory and economic pressure has changed the industry completely, making it harder to find a successful herbicide. Herbicide resistance has also become a major problem, increasing the difficulty of controlling weeds. As a result, the development of new molecules has become a rare event today. PMID:25104723

Kraehmer, Hansjoerg; Laber, Bernd; Rosinger, Chris; Schulz, Arno

2014-11-01

434

Nematode Interactions with Weeds and Sugarcane Mosaic Virus in Louisiana Sugarcane  

PubMed Central

Weeds did not appear to serve as reservoirs for phytophagous Louisiana sugarcane nematode populations except for Criconemella spp., Meloidogyne spp., Tylenchorhynchus annulatus, and total phytophagous nematode densities were lower on weed-stressed cane and were accompanied by reduced accumulations of free cysteine, proline, and 13 other free amino acids in sugarcane. A significant weed-virus interaction for sugarcane free cysteine accumulation was detected; T. annulatus populations were highly correlated (r = 0.59, P ? 0.001) with the weed-induced and virus-induced changes in free cysteine. Sugarcane nematodes interacted differently with the weed and virus stresses and changes in host plant stress-related free amino acid concentrations. PMID:19287686

Showler, A. T.; Reagan, T. E.; Shao, K. P.

1990-01-01

435

Effects of hand weeding strip and nitrogen fertilizer on corn plants.  

PubMed

The objective of the present research was to evaluate effects of different strip weed control associated with nitrogen fertilizer on corn applied after planting. The experiment was set and conducted in Botucatu, Săo Paulo State, Brazil, and the hybrid planted was Dekalb 333-B. A completely randomized block design with four replications was used. Experimental plots were disposed as a factorial scheme 2 x 2 x 4, constituted by two types of weeding on row (with or without manual hoeing), two types of weeding on inter-row (with or without manual hoeing), and four nitrogen levels applied after planting (00, 60, 90, and 120 kg ha(-1)). Plots were composed by six rows with 5 m length. Nitrogen fertilizer was applied at 35 days after emergence (d.a.e). For weed community it was evaluated: weed density, dominancy, frequency, and relative importance. The main weed species were: Brachiaria plantiginea, Amaranthus retroflexus, Bidens pilosa, Cyperus rotunds, Brachiaria decumbens, Euphorbia heterofila, Oxalis latifolia, Acanthospermum hispidum, Commelina benghalensis. It was evaluated corn height at 40 and 100 d.a.e., first ear insertion height at 100 d.a.e., and final grain yield at harvesting. Plants and first ear insertion height were affected when nitrogen fertilizer was not applied. Treatments without weed control showed that weed interfered negatively with plants height. There were no correlation between weeds and nitrogen fertilizer for all parameters evaluated. Parcels without weed showed the highest ear weights and final grain production. Treatments that received nitrogen fertilizer, independently of studied arrangement, provided higher yields. PMID:15656170

da Silva, Joăo Renato Vaz; Martins, Dagoberto; Cardoso, Leonildo A; Carbonari, Caio Antonio

2005-01-01

436

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

437

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

438

Weed Busters: How to Control Common (Annual) Broomweed  

E-print Network

for quail and other wild birds. Also, the plant?s canopy provides quail and other ground birds some protective cover from predators. Common broomweed is a prolific seed producer. It can readily germinate and grow into thick stands that completely shade... the timing and amount of winter rainfall. L-5461 1/05 How to Control Common (Annual) Broomweed Safe and effective three-step ways to control common broomweed Weed Treatment Series J. F. Cadenhead, Extension Range Specialist, Vernon Allan McGinty, Extension...

2005-03-07

439

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. PMID:16658159

Holm, Robert E.

1972-01-01

440

Cole Crops Weed Survey Form (9/12) Download at www.ipm.ucdavis.edu/FORMS www.ipm.ucdavis.edu  

E-print Network

Cole Crops Weed Survey Form (9/12) · Download at www.ipm.ucdavis.edu/FORMS www.ipm.ucdavis.edu Cole Crops Weed Survey ANNUAL CHECKLIST Supplement to UC IPM Pest Management Guidelines Grower of infestation for each weed species on your weed survey form. Use either a numeric scale from 1 to 5 (1 being

Ishida, Yuko

441

Weed Control Methods This information is not a substitute for pesticide labeling. Always read the product label before applying any pesticide. Always check NYS registration  

E-print Network

. It is a resource to compare weed control methods and herbicide label information. Thermal Mechanical BarrierWeed Control Methods This information is not a substitute for pesticide labeling. Always read effective on newly emerged annuals Small weeds Few, large weeds Long- term control Best on young annuals Air

Keinan, Alon

442

Evolution of herbicide resistance mechanisms in grass weeds.  

PubMed

Herbicide resistant weeds are becoming increasingly common, threatening global food security. Here, we present BrIFAR: a new model system for the functional study of mechanisms of herbicide resistance in grass weeds. We have developed a large collection of Brachypodium accessions, the BrI collection, representing a wide range of habitats. Wide screening of the responses of the accessions to four major herbicide groups (PSII, ACCase, ALS/AHAS and EPSPS inhibitors) identified 28 herbicide-resistance candidate accessions. Target-site resistance to PSII inhibitors was found in accessions collected from habitats with a known history of herbicide applications. An amino acid substitution in the psbA gene (serine264 to glycine) conferred resistance and also significantly affected the flowering and shoot dry weight of the resistant accession, as compared to the sensitive accession. Non-target site resistance to ACCase inhibitors was found in accessions collected from habitats with a history of herbicide application and from a nature reserve. In-vitro enzyme activity tests and responses following pre-treatment with malathion (a cytochrome-P450 inhibitor) indicated sensitivity at the enzyme level, and give strong support to diclofop-methyl and pinoxaden enhanced detoxification as NTS resistance mechanism. BrIFAR can promote better understanding of the evolution of mechanisms of herbicide resistance and aid the implementation of integrative management approaches for sustainable agriculture. PMID:25443832

Matzrafi, Maor; Gadri, Yaron; Frenkel, Eyal; Rubin, Baruch; Peleg, Zvi

2014-12-01

443

Weed vegetation ecology of arable land in Salalah, Southern Oman.  

PubMed

This paper applies multivariate statistical methods to a data set of weed relevés from arable fields in two different habitat types of coastal and mountainous escarpments in Southern Oman. The objectives were to test the effect of environmental gradients, crop plants and time on weed species composition, to rank the importance of these particular factors, and to describe the patterns of species composition and diversity associated with these factors. Through the application of TWINSPAN, DCA and CCA programs on data relating to 102 species recorded in 28 plots and farms distributed in the study area, six plant communities were identified: I- Dichanthium micranthum, II- Cynodon dactylon-D. micranthum, III- Convolvulus arvensis, IV- C. dactylon-Sonchus oleraceus, V- Amaranthus viridis and VI- Suaeda aegyptiaca-Achyranthes aspera. The ordination process (CCA) provided a sequence of plant communities and species diversity that correlated with some anthropogenic factors, physiographic variables and crop types. Therefore, length of time since farm construction, disturbance levels and altitude are the most important factors related to the occurrence of the species. The perennial species correlated with the more degraded mountain areas of new farm stands, whereas most of the annuals correlated with old lowland and less disturbed farms. PMID:23961246

El-Sheikh, Mohamed A

2013-07-01

444

Cuscuta jepsonii (Convolvulaceae): An invasive weed or an extinct endemic?  

PubMed

Despite their ecological significance, parasitic plants face more conservation challenges than do autotrophic plants. This is especially true for the groups that include weedy or invasive species such as Cuscuta. While approximately half of the Cuscuta (dodders) species may require conservation measures, the genus as a whole is sometimes posted on governmental lists of noxious or quarantine weeds. Our study challenges this stereotype and uses the case of C. jepsonii (Jepson's dodder) to illustrate the precarious biodiversity and conservation status faced by many dodder species. Until now, Jepson's dodder has been known only from its type collection. Consequently, its phylogenetic affinities, morphological variation, and ecology have remained unknown, and the species is currently ambiguously considered either synonymous to the invasive North American weed C. indecora or to an extinct endemic from California. Using molecular data from newly found collections, we infer that C. jepsonii belongs to C. californica species complex, instead of C. indecora clade. Also, we discuss the conservation of this species within the broader biological and ecological context of Cuscuta in general. PMID:21622360

Costea, Mihai; Stefanovic, Sasa

2009-09-01

445

Potential for phytoextraction of PCBs from contaminated soils using weeds.  

PubMed

A comprehensive investigation of the potential of twenty-seven different species of weeds to phytoextract polychlorinated biphenyls (PCBs) from contaminated soil was conducted at two field sites (Etobicoke and Lindsay) in southern Ontario, Canada. Soil concentrations were 31 microg/g and 4.7 microg/g at each site respectively. All species accumulated PCBs in their root and shoot tissues. Mean shoot concentrations at the two sites ranged from 0.42 microg/g for Chenopodium album to 35 microg/g for Vicia cracca (dry weight). Bioaccumulation factors (BAF=[PCB](plant tissue)/[PCB](mean soil)) at the two sites ranged from 0.08 for Cirsium vulgare to 1.1 for V. cracca. Maximum shoot extractions were 420 microg for Solidago canadensis at the Etobicoke site, and 120 microg for Chrysanthemum leucanthemum at the Lindsay site. When plant density was taken into account with a theoretical density value, seventeen species appeared to be able to extract a similar or greater quantity of PCBs into the shoot tissue than pumpkins (Curcurbita pepo ssp. pepo) which are known PCB accumulators. Therefore, some of these weed species are promising candidates for future phytoremediation studies. PMID:20483449

Ficko, Sarah A; Rutter, Allison; Zeeb, Barbara A

2010-07-15

446

Weed vegetation ecology of arable land in Salalah, Southern Oman  

PubMed Central

This paper applies multivariate statistical methods to a data set of weed relevés from arable fields in two different habitat types of coastal and mountainous escarpments in Southern Oman. The objectives were to test the effect of environmental gradients, crop plants and time on weed species composition, to rank the importance of these particular factors, and to describe the patterns of species composition and diversity associated with these factors. Through the application of TWINSPAN, DCA and CCA programs on data relating to 102 species recorded in 28 plots and farms distributed in the study area, six plant communities were identified: I- Dichanthium micranthum, II- Cynodon dactylon–D. micranthum, III- Convolvulus arvensis, IV- C. dactylon–Sonchus oleraceus, V- Amaranthus viridis and VI- Suaeda aegyptiaca–Achyranthes aspera. The ordination process (CCA) provided a sequence of plant communities and species diversity that correlated with some anthropogenic factors, physiographic variables and crop types. Therefore, length of time since farm construction, disturbance levels and altitude are the most important factors related to the occurrence of the species. The perennial species correlated with the more degraded mountain areas of new farm stands, whereas most of the annuals correlated with old lowland and less disturbed farms. PMID:23961246

El-Sheikh, Mohamed A.

2013-01-01

447

The Use of Protein Hydrolysates for Weed Control  

NASA Astrophysics Data System (ADS)

Corn gluten meal, the protein fraction of corn (Zea mays L.) grain, is commercially used as a natural weed control agent and nitrogen source in horticultural crops and in the turf and ornamental markets. Corn gluten hydrolysate, a water soluble form of gluten meal, has also been proposed for the same purpose, although it could be sprayed on the soil rather than applied in the granular form. Five depeptides, glutaminyl-glutamine (Gln-Gln), glycinyl-alanine (Gly-Ala), alanyl-­glutamine (Ala-Glu), alanyl-asparagine (Ala-Asp), and alaninyl-alanine (Ala-Ala) and a pentapeptide leucine-serine-proline-alanine-glutamine (Leu-Ser-Pro-Ala-Gln) were identified as the active components of the hydrolysate. Microscopic analysis revealed that Ala-Ala acted on some metabolic process rather than directly on the mitotic apparatus. Similar to the chloracetamides and sulfonyl-urea hebicides, Ala-Ala inhibits cell division rather than disrupting of cell division processes. Cellular ultrastructure changes caused by exposure to Ala-Ala implicate Ala-Ala as having membrane-disrupting characteristics similar to several synthetic herbicides. The potential use of the hydrolysate and the peptides as weed controls is discussed.

Christians, Nick; Liu, Dianna; Unruh, Jay Bryan

448

A Novel Approach for Weed Type Classification Based on Shape Descriptors and a Fuzzy Decision-Making Method  

PubMed Central

An important objective in weed management is the discrimination between grasses (monocots) and broad-leaved weeds (dicots), because these two weed groups can be appropriately controlled by specific herbicides. In fact, efficiency is higher if selective treatment is performed for each type of infestation instead of using a broadcast herbicide on the whole surface. This work proposes a strategy where weeds are characterised by a set of shape descriptors (the seven Hu moments and six geometric shape descriptors). Weeds appear in outdoor field images which display real situations obtained from a RGB camera. Thus, images present a mixture of both weed species under varying conditions of lighting. In the presented approach, four decision-making methods were adapted to use the best shape descriptors as attributes and a choice was taken. This proposal establishes a novel methodology with a high success rate in weed species discrimination. PMID:25195854

Herrera, Pedro Javier; Dorado, José.; Ribeiro, Ángela.

2014-01-01

449

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

PubMed Central

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

2013-01-01

450

Pretreatment of Siam weed stem by several chemical methods for increasing the enzymatic digestibility.  

PubMed

Siam weed [Chromolaena odorata (L.) King & Robinson], an invasive exotic weed in China, was proposed as a feedstock for bioethanol production. This would be a promising way of using for an invasive weed that needs management and control. It was found that the glucan content of the weed stem was similar to that of sugarcane bagasse, but higher than those of corn stover and wheat straw. Several chemical pretreatment methods were applied to the weed stem to increase its enzymatic digestibility. Mild sulfuric acid (<120 degrees C) or alkali pretreatment did not markedly increase the enzymatic digestibility. However, peracetic acid (PAA) pretreatment dramatically enhanced the enzymatic hydrolysis of the weed stem. Compared to some other common agricultural residues, the weed stem was more difficult to pretreat and digest by cellulase. Fourier transform infrared (FTIR) spectra analysis indicated that the cellulose-related bands became more intensive after pretreatment, especially for PAA-pretreated samples. According to X-ray diffraction spectra, the biomass solids had higher crystallinity indices after pretreatment, although these indices were similar for all of the pretreated samples. PMID:20349449

Zhao, Xuebing; Zhang, Lihua; Liu, Dehua

2010-05-01

451

Accuracy and feasibility of optoelectronic sensors for weed mapping in wide row crops.  

PubMed

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

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

2011-01-01

452

Climate Effects and Feedback Structure Determining Weed Population Dynamics in a Long-Term Experiment  

PubMed Central

Pest control is one of the areas in which population dynamic theory has been successfully applied to solve practical problems. However, the links between population dynamic theory and model construction have been less emphasized in the management and control of weed populations. Most management models of weed population dynamics have emphasized the role of the endogenous process, but the role of exogenous variables such as climate have been ignored in the study of weed populations and their management. Here, we use long-term data (22 years) on two annual weed species from a locality in Central Spain to determine the importance of endogenous and exogenous processes (local and large-scale climate factors). Our modeling study determined two different feedback structures and climate effects in the two weed species analyzed. While Descurainia sophia exhibited a second-order feedback and low climate influence, Veronica hederifolia was characterized by a first-order feedback structure and important effects from temperature and rainfall. Our results strongly suggest the importance of theoretical population dynamics in understanding plant population systems. Moreover, the use of this approach, discerning between the effect of exogenous and endogenous factors, can be fundamental to applying weed management practices in agricultural systems and to controlling invasive weedy species. This is a radical change from most approaches currently used to guide weed and invasive weedy species managements. PMID:22272362

Lima, Mauricio; Navarrete, Luis; González-Andujar, José Luis

2012-01-01

453

Climate effects and feedback structure determining weed population dynamics in a long-term experiment.  

PubMed

Pest control is one of the areas in which population dynamic theory has been successfully applied to solve practical problems. However, the links between population dynamic theory and model construction have been less emphasized in the management and control of weed populations. Most management models of weed population dynamics have emphasized the role of the endogenous process, but the role of exogenous variables such as climate have been ignored in the study of weed populations and their management. Here, we use long-term data (22 years) on two annual weed species from a locality in Central Spain to determine the importance of endogenous and exogenous processes (local and large-scale climate factors). Our modeling study determined two different feedback structures and climate effects in the two weed species analyzed. While Descurainia sophia exhibited a second-order feedback and low climate influence, Veronica hederifolia was characterized by a first-order feedback structure and important effects from temperature and rainfall. Our results strongly suggest the importance of theoretical population dynamics in understanding plant population systems. Moreover, the use of this approach, discerning between the effect of exogenous and endogenous factors, can be fundamental to applying weed management practices in agricultural systems and to controlling invasive weedy species. This is a radical change from most approaches currently used to guide weed and invasive weedy species managements. PMID:22272362

Lima, Mauricio; Navarrete, Luis; González-Andujar, José Luis

2012-01-01

454

Breeding cereal crops for enhanced weed suppression: optimizing allelopathy and competitive ability.  

PubMed

Interest in breeding grain crops with improved weed suppressive ability is growing in response to the evolution and rapid expansion of herbicide resistant populations in major weeds of economic importance, environmental concerns, and the unmet needs of organic producers and smallholder farmers without access to herbicides. This review is focused on plant breeding for weed suppression; specifically, field and laboratory screening protocols, genetic studies, and breeding efforts that have been undertaken to improve allelopathy and competition in rice, wheat, and barley. The combined effects of allelopathy and competition determine the weed suppressive potential of a given cultivar, and research groups worldwide have been working to improve both traits simultaneously to achieve maximum gains in weed suppression. Both allelopathy and competitive ability are complex, quantitatively inherited traits that are heavily influenced by environmental factors. Thus, good experimental design and sound breeding procedures are essential to achieve genetic gains. Weed suppressive rice cultivars are now commercially available in the U.S. and China that have resulted from three decades of research. Furthermore, a strong foundation has been laid during the past 10 years for the breeding of weed suppressive wheat and barley cultivars. PMID:23385368

Worthington, Margaret; Reberg-Horton, Chris

2013-02-01

455

Combining spatial and spectral information to improve crop/weed discrimination algorithms  

NASA Astrophysics Data System (ADS)

Reduction of herbicide spraying is an important key to environmentally and economically improve weed management. To achieve this, remote sensors such as imaging systems are commonly used to detect weed plants. We developed spatial algorithms that detect the crop rows to discriminate crop from weeds. These algorithms have been thoroughly tested and provide robust and accurate results without learning process but their detection is limited to inter-row areas. Crop/Weed discrimination using spectral information is able to detect intra-row weeds but generally needs a prior learning process. We propose a method based on spatial and spectral information to enhance the discrimination and overcome the limitations of both algorithms. The classification from the spatial algorithm is used to build the training set for the spectral discrimination method. With this approach we are able to improve the range of weed detection in the entire field (inter and intra-row). To test the efficiency of these algorithms, a relevant database of virtual images issued from SimAField model has been used and combined to LOPEX93 spectral database. The developed method based is evaluated and compared with the initial method in this paper and shows an important enhancement from 86% of weed detection to more than 95%.

Yan, L.; Jones, G.; Villette, S.; Paoli, J. N.; Gée, C.

2012-01-01

456

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

2013-04-01

457

Unearthing the impact of human disturbance on a notorious weed.  

PubMed

Large-scale anthropogenic changes in the environment are reshaping global biodiversity and the evolutionary trajectory of many species. Evolutionary mechanisms that allow organisms to thrive in this rapidly changing environment are just beginning to be investigated (Hoffmann & Sgrň 2011; Colautti & Barrett 2013). Weedy and invasive species represent 'success stories' for how species can cope with human modified environments. As introduced species have spread within recent times, they provide the unique opportunity to track the genetic consequences of rapid range expansion through time and space using historic DNA samples. Using modern collections and herbarium specimens dating back to 1873, Martin et al. (2014) have provided a more complete understanding of the population history of the invasive, agricultural weed, common ragweed (Ambrosia artemisiifolia; Fig. 1) in its native range with surprising results. They find that the recent population explosion of common ragweed in North America coincided with substantial shifts in population genetic structure with implications for invasion. PMID:24766630

Hodgins, Kathryn

2014-05-01

458

Anti-tumorigenic components of a sea weed, Eeteromorpha clathrata.  

PubMed

Anti-tumorigenic action of compounds in some seaweed was evaluated by using selective cytotoxicity against a transformed mouse 3T3 cell (SV-T2) and its normal counter part. The extracts of seaweeds (Wakame, Konbu, Mirin, Aosa, and Sujiaonori) were added to the cells in 96 well microplate. The viability of the cell was measured at 24 hr after sample addition. Of the five weeds, the ethanol extracts from Sujiaonori exhibited the selective cytotoxicity. The ethanol extracts from Sujiaonori was applied to gel permeation chromatography on Sephadex G-50. The anti-cancer activity was detected in two fractions with high molecular weight near void volume and with small molecular weight. The high molecular weight fractions had absorbance at 280 nm, suggesting that they contained proteineous substances. The small molecular weight fractions were estimated to be around 500 Dalton. PMID:15630263

Tang, Hanjun; Inoue, Mamiko; Uzawa, Yuki; Kawamura, Yukio

2004-01-01

459

Optical parameters of leaves of seven weed species  

NASA Technical Reports Server (NTRS)

Absorption coefficient (k), infinite reflectance (R inf.) and scattering coefficient (s) were tabulated for five wavelengths and analyzed for statistical differences for seven weed species. The wavelengths were: 0.55, 0.65, 0.85, 1.65, and 2.20 microns. The R inf. of common lambsquarters (Chenopodium album L.), johnsongrass (Sorghum halepense L. Pers.), and annual sowthistle (Sonchus oleraceus L.) leaves at the 0.85 micron wavelength were significantly (p = 0.05) higher than for sunflower (Helianthus annuus L.), ragweed parthenium (parthenium hysterophorus L.), or London rocket (Sisymbrium irio L.). Annual sowthistle had the largest k value, and Palmer amaranth (Amaranthus palmeri S. Wats.) had the smallest k value at the 0.65 micron chlorophyll absorption wavelength. In general, johnsongrass, ragweed parthenium, and London rocket had the largest s values among the five wavelengths, whereas annual sowthistle and Palmer amaranth were usually lowest.

Gausman, H. W.; Menges, R. M.; Richardson, A. J.; Walter, H.; Rodriguez, R. R.; Tamez, S. (principal investigators)

1982-01-01

460

Optical parameters of leaves of seven weed species  

NASA Technical Reports Server (NTRS)

The absorption coefficient (k), infinite reflectance (R), and scattering coefficient (s) were tabulated for five wavelengths and analyzed for statistical differences for seven weed species. The wavelengths were: 0.55-micrometer, 0.65-micrometers, 0.85-micrometer, 1.65-micrometers, and 2.20-micrometer. The R of common lambsquarters (Chenopodium album L.), Johnsongrass (Sorghum halepense (L.) Pers.), and annual sowthistle (Sonchus oleraceus L.) leaves at the 0.85-micrometer wavelength were significantly (p=0.05) higher than for sunflower (Heliantus annus L.), ragweed parthenium (Parthenium hysterophorus L.), or London rocket (Sisymbrium irio L.). Annual sowthistle had the largest k value, and Plamer amaranth (Amaranthus palmer S. Wats.) had the smallest k value at the 0.65 approximately chlorophyll absorption wavelength. In general, john-songress, ragweed parthenium, or London rocket had the largest s values among the five wavelengths, wereas annual sowthistle and plamar amaranth were usually lowest.

Gausman, H. W.; Menges, R. M.; Richardson, A. J.; Walter, H.; Rodriguez, R. R.; Tamez, S. (principal investigators)

1982-01-01

461

Weeds Gone Wild: Alien Plant Invaders of Natural Areas  

NSDL National Science Digital Library

Weeds Gone Wild is a project of Plant Conservation Alliance (reviewed in the January 19, 2000 Scout Report for Science & Engineering-- http://scout.cs.wisc.edu/report/sci-eng/2000/se-000119.html#16}), a consortium of federal and non-federal agencies dedicated to protecting native plants. Targeting viewers ranging from the general public to researchers, this site provides information on "the serious threat and impacts of invasive alien (exotic, non-native) plants to the native flora, fauna, and natural ecosystems of the United States." To that end, the site includes a compiled national list of many invasive plants (Aquatics, Herbs, Vines, Shrubs and Trees); comprehensive background information on invasive species; illustrated fact sheets with plant descriptions, native range, distribution, and habitat in the US; management options and suggested alternative native plants; and other information. A collection of links of experts and organizations rounds out this well-conceived site.

462

Weed control on hard surfaces in The Netherlands.  

PubMed

The non-agricultural use of pesticides in The Netherlands declined in the period 1986-2001 from 127000 to 40000 kg AI per annum. However use on pavements rose from 23% to 50% of the total non-agricultural use. To diminish the dependency on herbicides, both preventive and curative non-chemical weed control methods have been examined. In the future both mechanical and thermal methods can be improved. On a flat pavement mechanical methods are preferred because they are more effective. Two approaches are used by municipalities to lower the environmental impact of the use of herbicides on pavements. The first is to phase out the use of chemicals on hard surfaces and the second is the integrated approach in which herbicides are not prohibited, but used only on places and at times when the risk of run-off is below a mutually accepted level. Both approaches can be effective. PMID:15198333

Kempenaar, Corné; Spijker, Joop H

2004-06-01

463

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

PubMed

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

Rajiv, P; Rajeshwari, Sivaraj; Rajendran, Venckatesh

2014-11-01

464

Estimation of base temperatures for nine weed species.  

PubMed

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

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

2000-02-01

465

Carboxylesterase activities toward pesticide esters in crops and weeds.  

PubMed

Proteins were extracted from maize, rice, sorghum, soybean, flax and lucerne; the weeds Abutilon theophrasti, Echinochloa crus-galli, Phalaris canariensis, Setaria faberii, Setaria viridis, Sorghum halepense and the model plant Arabidopsis thaliana and assayed for carboxylesterase activity toward a range of xenobiotics. These included the pro-herbicidal esters clodinafop-propargyl, fenoxaprop-ethyl, fenthioprop-ethyl, methyl-2,4-dichlorophenoxyacetic acid (2,4-d-methyl), bromoxynil-octanoate, the herbicide-safener cloquintocet-mexyl and the pyrethroid insecticide permethrin. Highest activities were recorded with alpha-naphthyl acetate and methylumbelliferyl acetate. Esters of p-nitrophenol were also readily hydrolysed, with turnover declining as the chain length of the acyl component increased. Activities determined with model substrates were much higher than those observed with pesticide esters and were of limited value in predicting the relative rates of hydrolysis of the crop protection agents. Substrate preferences with the herbicides were typically 2,4-d-methyl>clodinafop-propargyl>fenthioprop-ethyl, fenoxaprop-ethyl and bromoxynil-octanoate. Isoelectric focussing in conjunction with staining for esterase activity using alpha-naphthyl acetate as substrate confirmed the presence of multiple carboxylesterase isoenzymes in each plant, with major qualitative differences observed between species. The presence of serine hydrolases among the resolved isoenzymes was confirmed through their selective inhibition by the organophosphate insecticide paraoxon. Our studies identify potentially exploitable differences between crops and weeds in their ability to bioactivate herbicides by enzymic hydrolysis and also highlight the usefulness of Arabidopsis as a plant model to study xenobiotic biotransformation. PMID:17078983

Gershater, Markus; Sharples, Kate; Edwards, Robert

2006-12-01

466

Augmentation and Aldicarb Treatment of Nematodes in Selected Sugarcane Weed Habitats  

PubMed Central

In a single experiment, field-grown Louisiana sugarcane was augmented with phytoparasitic nematodes, treated with aldicarb, or left untreated in both weedy and weed-free habitats to study interactions among nematodes, weeds, sugarcane, and sugarcane free amino acid titers. Aldicarb reduced three of the six phytoparasitic nematode genera at various times during the two growing seasons and was associated with 17% more free proline in the sugarcane. Nematode augmentation resulted in higher field populations of Meloidogyne spp. Free cysteine, histidine, proline, and serine concentrations in sugarcane were lower where nematodes were added. Densities of Tylenchorhynchus annulatus and total phytoparasitic nematodes were lower in weedy habitats compared to weed-free conditions. Sixteen of the 17 sugarcane free amino acids were significantly lower in weed-free areas. It is suggested that further research be conducted on the relationship of plant stresses to free amino acid levels to better understand plant-mediated interactions among crop pests. PMID:19283191

Showler, A. T.; Reagan, T. E.; Flynn, J. L.

1991-01-01

467

An Introduced Insect Biological Control Agent Preys on an Introduced Weed Biological Control Agent.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Biotic interference, especially by generalist predators, has been implicated in preventing establishment or limiting the impact of introduced weed biological control agents. Boreioglycaspis melaleucae Moore (Homoptera: Psyllidae) was released into Florida in 2002 as part of a classical biological c...

468

Engineering phosphorus metabolism in plants to produce a dual fertilization and weed control system.  

PubMed

High crop yields depend on the continuous input of orthophosphate (PO(4)(?3))-based fertilizers and herbicides. Two major challenges for agriculture are that phosphorus is a nonrenewable resource and that weeds have developed broad herbicide resistance. One strategy to overcome both problems is to engineer plants to outcompete weeds and microorganisms for limiting resources, thereby reducing the requirement for both fertilizers and herbicides. Plants and most microorganisms are unable to metabolize phosphite (PO(3)(?3)), so we developed a dual fertilization and weed control system by generating transgenic plants that can use phosphite as a sole phosphorus source. Under greenhouse conditions, these transgenic plants require 30–50% less phosphorus input when fertilized with phosphite to achieve similar productivity to that obtained by the same plants using orthophosphate fertilizer and, when in competition with weeds, accumulate 2–10 times greater biomass than when fertilized with orthophosphate. PMID:22922674

López-Arredondo, Damar Lizbeth; Herrera-Estrella, Luis

2012-09-01

469

LRES 443 -WEED ECOLOGY & MANAGEMENT Instructor: Dr. Bruce Maxwell TA: Melissa Bridges  

E-print Network

to survive and prosper in natural and human disturbed ecosystems. 3. To become familiar with terminology Quiz. Herbicides & Soil (PGC 211) 11-24 TU Weed Control Exam 11-26 TH THANKSGIVING HOLIDAY NO LAB 12

Maxwell, Bruce D.

470

Classification of Weed Species Using Artificial Neural Networks Based on Color Leaf Texture Feature  

NASA Astrophysics Data System (ADS)

The potential impact of herbicide utilization compel people to use new method of weed control. Selective herbicide application is optimal method to reduce herbicide usage while maintain weed control. The key of selective herbicide is how to discriminate weed exactly. The HIS color co-occurrence method (CCM) texture analysis techniques was used to extract four texture parameters: Angular second moment (ASM), Entropy(E), Inertia quadrature (IQ), and Inverse difference moment or local homogeneity (IDM).The weed species selected for studying were Arthraxon hispidus, Digitaria sanguinalis, Petunia, Cyperus, Alternanthera Philoxeroides and Corchoropsis psilocarpa. The software of neuroshell2 was used for designing the structure of the neural network, training and test the data. It was found that the 8-40-1 artificial neural network provided the best classification performance and was capable of classification accuracies of 78%.

Li, Zhichen; An, Qiu; Ji, Changying

471

Cover-Crop RollerCrimper Contributes to Weed Management in No-Till Soybean  

E-print Network

, Amaranthus rudis Sauer, AMARU; giant foxtail, Setaria faberi Herrm., SETFA; hairy vetch, Vicia villosa Roth-crop termination, Glycine max establishment, weed suppression, Secale cereale, Vicia villosa, organic, low external

Sims, Gerald K.

472

Herbicide-resistant weeds: from research and knowledge to future needs  

PubMed Central

Synthetic herbicides have been used globally to control weeds in major field crops. This has imposed a strong selection for any trait that enables plant populations to survive and reproduce in the presence of the herbicide. Herbicide resistance in weeds must be minimized because it is a major limiting factor to food security in global agriculture. This represents a huge challenge that will require great research efforts to develop control strategies as alternatives to the dominant and almost exclusive practice of weed control by herbicides. Weed scientists, plant ecologists and evolutionary biologists should join forces and work towards an improved and more integrated understanding of resistance across all scales. This approach will likely facilitate the design of innovative solutions to the global herbicide resistance challenge. PMID:24478803

Busi, Roberto; Vila-Aiub, Martin M; Beckie, Hugh J; Gaines, Todd A; Goggin, Danica E; Kaundun, Shiv S; Lacoste, Myrtille; Neve, Paul; Nissen, Scott J; Norsworthy, Jason K; Renton, Michael; Shaner, Dale L; Tranel, Patrick J; Wright, Terry; Yu, Qin; Powles, Stephen B

2013-01-01

473

Weed Busters: How to take the Sting out of Texas Bull Nettle  

E-print Network

the Sting out of Texas Bullnettle Safe and effective three-step ways to control Texas bullnettle Weed Treatment Series Charles R. Hart, Extension Range Specialist, Stephenville Robert K. Lyons, Extension Range Specialist, Uvalde Allan McGinty, Extension...

Hart, Charles R.; Lyons, Robert K.; McGinty, Allan

2007-04-10

474

[Epiphytic phase of Erwinia amylovora and Pseudomonas syringae pv. syringae on orchard weeds].  

PubMed

Epiphyte phase of phytopathogenic bacteria Erwinia amylovora and Pseudomonas syringae pv. syringae on the fruit garden weeds has been studied. It has been shown that healthy weeds of the fruit-tree stands can be an ecologic niche for Erwinia amylovora and Pseudomonas syringae pv. syringae which gives them an opportunity to survive as epiphytes. Strains of Pseudomonas syringae pv. syringae were isolated from seven studied weeds (47-49%) during the whole vegetation period (March-October). Strains of Erwinia amylovora distributed on the leaves of Arctium lappa L., Amarantus reflexus L. and Tripleurospermum inodorum (L) Sch. Vir. in the period of the disease intensive development on the pear-tree (June-August). Cells of Erwinia amylovora were isolated from 12-14% of selected weeds. PMID:11785263

Gvozdiak, R I; Lukach, M I

2001-01-01

475

Effect of pre-planting irrigation, maize planting pattern and nitrogen on weed seed bank population.  

PubMed

Pre-planting irrigation and planting patterns are important factors in weed management that effect on seed bank. Additionally, the nitrogen is the most important factor in plant growth that affects weed-crop competition and ultimately, seed rain into the soil. A field experiment was conducted to study the effect of nitrogen application rates, pre-planting irrigation and maize planting patterns on weed seed bank population. Experimental factors were nitrogen rates at 4 levels (200, 300, 400 and 500 kg per hectare) as main plot; and pre-planting irrigation at 2 levels (irrigation before planting plus weeding emerged seedlings and, irrigation after sowing), and maize planting patterns (one-row and two-row planting of maize with same density per square of row length) that were assigned in a factorial arrangement to the sub plots. Soil samples were taken at the beginning of the season (before planting of maize) and at the end of the season (after harvest) at depth of 0-5 cm in the fixed quadrates (60 cm x 60 cm). The weed seeds were extracted from the soil samples and were identified using standard methods. The majority of weed seed bank populations included 6 weed species: Portulaca oleracea, Chenopodium album, Amaranthus retroflexus, Sorghum halepense, Daturea stramonium, Xanthium strumarium. Results showed that population of weed seed bank increased significantly with increasing nitrogen rate. The increasing rate was different between one-row and two-row planting patterns. The parameters indicated that seed bank population was much higher in a one row planting pattern of maize. With two-row planting, seed bank was decreased by 34, 26, 20 and 5% at 200, 300, 400 and 500 kg N/ha, respectively. Pre-planting irrigation was also found an effective implement to reduce the weed seed bank. When pre-planting irrigation was applied, seed bank was decreased by 57, 43, 34 and 9% at 200, 300, 400 and 500 kg N/ha. Increasing nitrogen because of weed's better growth and higher seed production neutralized the decreasing effect of pre-planting irrigation and two-row planting of maize on weed seed bank population. PMID:22696965

Hemmati, E; Vazan, S; Oveisi, M

2011-01-01

476

G81-551 Ecofarming: Spring Row Crop Planting and Weed Control in Winter Wheat Stubble  

Microsoft Academic Search

Weed control, stubble management and planters for planting in winter wheat stubble are covered here.\\u000aPlanting corn, sorghum or soybeans into untilled, weed-free winter wheat stubble that is 10 months old is an accepted practice in the Central Great Plains States. In Nebraska, this system is known as ecofallow. Treating the stubble with herbicides following wheat harvest (ecofallow) offers several

Gail A. Wicks; Norman L. Klocke

1981-01-01

477

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

Microsoft Academic Search

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.

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

2008-01-01

478

[Fast catalogue of alien invasive weeds by Vis/NIR spectroscopy].  

PubMed

The feasibility of visible and short-wave near-infrared spectroscopy (VIS/WNIR) techniques as means for the nondestructive and fast detection of alien invasive weeds was evaluated. Selected sensitive bands were found validated. In the present study, 3 kinds of alien invasive weeds, Veronica persica, Veronica polita, and Veronica arvensis Linn, and one kind of local weed, Lamiaceae amplexicaule Linn, were employed. The results showed that visible and NIR (Vis/NIR) technology could be introduced in classification of the alien invasive weeds or local weed with the similar outline. Thirty x 4 weeds samples were randomly selected for the calibration set, while the remaining 20 x 4 samples for the prediction set. Smoothing methods of moving average and standard normal variate (SNV) were used to pretreat spectra data. Based on principal components analysis, soft independent models of class analogy (SIMCA) were applied to make the model. Four frontal principal components of each catalogues were applied as the input of SIMCA, and with a significance level of 0.05, recognition ratio of 78.75% was obtained. The average prediction result is 90% except for Veronica polita. According to the modeling power of each spectra data in SIMCA, some possible sensitive bands, 496-521, 589-626 and 789-926 nm, were founded. By using these possible sensitive bands as the inputs of least squares support vector machine (LS-SVM), and setting the result of LS-SVM as the object function value of genetic algorithm (GA), mutational rate, crossover rate and population size were set up as 0.9, 0.5 and 50 respectively. Finally recognition ratio of 95.63% was obtained. The prediction results of 95.63% indicated that the selected wavelengths reflected the main characteristics of the four weeds, which proposed a new way to accelerate the research on cataloguing alien invasive weeds. PMID:20101962

Yu, Jia-Jia; Zou, Wei; He, Yong; Xu, Zheng-Hao

2009-11-01

479

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

480

Evaluation of the weed flora of Egypt from Predynastic to Graeco-Roman times  

Microsoft Academic Search

Macrofossils of weeds retrieved from archaeological sediments in Egypt are discussed in terms of their presence, preservation and representation significance. The study reveals 112 field weeds from 61 archaeological sites dating from Predynastic times (4500 B.C.) up to the Graeco-Roman period (A.D. 395). Most of the remains were preserved by desiccation. The 112 listed species include 24 taxa from Predynastic

Ahmed Gamal El-Din Fahmy; El-Din Fahmy

1997-01-01

481

Tillage system did not affect weed diversity in a 23-year experiment in Mediterranean dryland  

Microsoft Academic Search

This study investigated whether the choice of a tillage system (no-tillage, minimum tillage or traditional tillage) affected weed diversity in a 23 years cereal–leguminous rotation system in Spain. Weed diversity was assessed using common diversity indices: species richness, Shannon's index and Pieloús evenness. Linear mixed-effects models were employed to compare the tillage systems. It was found that after 23 years

E. Hernandez Plaza; M. Kozak; L. Navarrete; J. L. Gonzalez-Andujar

2011-01-01

482

Suitability of weed species prevailing in Spanish vineyards as hosts for root-knot nematodes  

Microsoft Academic Search

Commercial vineyards in southern Spain were surveyed and sampled during October to December 2004 to determine the extent to\\u000a which common weeds present were suitable hosts of root-knot nematodes infesting soils of those vineyards. Seven weed species\\u000a commonly growing in grapevine soils in southern Spain were found infected by either Meloidogyne incognita or M. javanica: Amaranthus retroflexus (redroot pigweed), Anchusa

P. Castillo; H. F. Rapoport; J. E. Palomares Rius; R. M. Jiménez Díaz

2008-01-01

483

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

484

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. PMID:17786217

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

2007-01-01

485

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

2007-01-01

486

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

E-print Network

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) onEchinochloa 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.

Simon L. Zeller; Helmut Br; Bernhard Schmid

487

Studies on seed germination and growth in weed species of rice field under salinity stress.  

PubMed

An investigation was made to see the salt tolerance of 10 weed species of rice. Properly dried and treated seeds of weed species were placed on 9 cm diameter petridishes lined with Whatman No. 1 filter paper under 6 salinity regimes, viz. 0 (control), 4, 8, 16, 24 and 32 dS m(-1). The petri dishes were then kept in germinator at 25 +/- 1.0 degrees C and 12 hr light. The number of germinated seeds were recorded daily. The final germination percentage, germination index (GI), seedling vigour index, mean germination time and time for 50% germination were estimated. Root and shoot lengths of the weed seedlings were measured at 20 days after salt application and relative growth values were calculated. Results revealed that salinity decreased final germination percentage, seed of germination as measured by GI, and shoot and root length in all the species. Germination of most of the weed seeds was completely arrested (0) at 32 dS m(-1) salinity except in E. colona (12%) and C. iria (13.9%). The species C. iria, E. colona, J. linifolia and E. crusgalli showed better germination (above 30%) upto 24 dS m(-1) salinity level and were regarded as salt-tolerant weed species. J. linifolia, F. miliacea, L. chinensis and O. sativa L. (weedy rice) were graded as moderately tolerant and S. zeylanica, S. grosus and C. difformis were regarded as least tolerant weed species. PMID:22319865

Hakim, M A; Juraimi, Abdul Shukor; Hanafi, M M; Selamat, A; Ismail, Mohd Razi; Karim, S M Rezaul

2011-09-01

488

[Interference of allelopathic rice Huakangcao 78 on weeds under different ecological conditions].  

PubMed

A pot culture experiment was conducted to examine the interference effectiveness of allelopathic rice Huakangcao 78 on weeds Echinochloa crusgalli L., Cyperus difformis L., and Eclipta prostrata L. as affected by rice leaf age during transplanting, plant density, and soil surface water depth and its retaining days. The results showed that Huakangcao 78 could significantly reduce the dry weight of weeds compared with non-allelopathic rice Lemont. The control effectiveness of Huakangcao 78 on E. crusgalli L. was better when the weed was at 0-1.5 leaf age than at 1.5-2.4 leaf age, and that on C. difformis L. was better when the weed was at 0-0.3 leaf age than at 0.8-2.0 leaf age. The interactive effectiveness between rice leaf age during transplanting and plant density on weed control was better than that between the leaf age and soil surface water depth and its retaining days. To increase the rice leaf age during transplanting and plant density could significantly promote the control effectiveness of Huakangcao 78 on weeds. PMID:17147174

Wu, Jinglun; Li, Yongfeng; Chen, Zhishi; Wang, Yizhuan

2006-09-01

489

Weed seed bank composition under three long-term tillage regimes on a fine sandy loam in Atlantic Canada  

Microsoft Academic Search

Tillage systems can influence weed seed viability and the distribution with depth of weed seeds in soil. To investigate this ‘tillage effect’, weed seed bank composition was determined at two soil depths (0–10 and 10–20cm) in three tillage systems [mouldboard plough (MP), shallow tillage (ST), and direct drilling (DD)] established for 14 years on a sandy loam (Podzol) in Prince

M. R. Carter; J. A. Ivany

2006-01-01

490

Use of glufosinate-ammonium to control cruciferous weed species in glufosinate-resistant winter oilseed rape  

Microsoft Academic Search

Weed control is an important component of integrated cropping systems. However, cruciferous weeds are difficult to control in conventional winter oilseed rape (Brassica napus L.) and new herbicide options are needed. The aim of this study was to determine the potential for use of glufosinate-ammonium (2-amino-4-(hydroxymethyl-phosphinyl)-butanoic acid) as a flexible post-emergence herbicide for control of cruciferous weeds in glufosinate-resistant winter

U. Merkel; G.-W. Rathke; C. Schuster; K. Warnstorff; W. Diepenbrock

2004-01-01

491

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

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

2013-01-01

492

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. PMID:24146963

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

2013-01-01

493

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

494

Cover Crop Residue and Organic Mulches Provide Weed Control during Limited-Input No-Till Collard Production  

Microsoft Academic Search

Limited input producers may adopt no-till production 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 forage soybean summer cover crop and three types of organic mulches applied after collard (Brassica oleracea L.) planting.

Michael J. Mulvaney; Andrew J. Price; C. Wesley Wood

2011-01-01

495

[Effects of different multiple cropping systems on paddy field weed community under long term paddy-upland rotation].  

PubMed

Based on a long term field experiment, this paper studied the effects of different multiple cropping systems on the weed community composition and species diversity under paddy-upland rotation. The multiple cropping rotation systems could significantly decrease weed density and inhibited weed growth. Among the rotation systems, the milk vetch-early rice-late maize --> milk vetchearly maize intercropped with early soybean-late rice (CCSR) had the lowest weed species dominance, which inhibited the dominant weeds and decreased their damage. Under different multiple cropping systems, the main weed community was all composed of Monochoia vaginalis, Echinochloa crusgalli, and Sagittaria pygmae, and the similarity of weed community was higher, with the highest similarity appeared in milk vetch-early rice-late maize intercropped with late soybean --> milk vetch-early maize-late rice (CSCR) and in CCSR. In sum, the multiple cropping rotations in paddy field could inhibit weeds to a certain extent, but attentions should be paid to the damage of some less important weeds. PMID:24417111

Yang, Bin-Juan; Huang, Guo-Qin; Xu, Ning; Wang, Shu-Bin

2013-09-01

496

Effects of weed cover composition on insect pest and natural enemy abundance in a field of Dracaena marginata (Asparagales: Asparagaceae) in Costa Rica.  

PubMed

Weeds and their influence on pest and natural enemy populations were studied on a commercial ornamental farm during 2009 in the Atlantic Zone of Costa Rica. A baseline survey of the entire production plot was conducted in February, along a 5 by 5 m grid to characterize and map initial weed communities of plants, cicadellids, katydids, and armored scales. In total, 50 plant species from 21 families were found. Seven weed treatments were established to determine how weed manipulations would affect communities of our targeted pests and natural enemies. These treatments were selected based on reported effects of specific weed cover on herbivorous insects and natural enemies, or by their use by growers as a cover crop. Treatments ranged from weed-free to being completely covered with endemic species of weeds. Although some weed treatments changed pest abundances, responses differed among arthropod pests, with the strongest effects observed for Caldwelliola and Empoasca leafhoppers. Removal of all weeds increased the abundance of Empoasca, whereas leaving mostly cyperacaeous weeds increased the abundance of Caldwelliola. Weed manipulations had no effect on the abundance of katydid and scale populations. No weed treatment reduced the abundance of all three of the target pests. Differential responses of the two leafhopper species to the same weed treatments support hypotheses, suggesting that noncrop plants can alter the abundance of pests through their effects on arthropod host finding and acceptance, as well as their impacts on natural enemies. PMID:24517852

Sadof, Clifford S; Linkimer, Mildred; Hidalgo, Eduardo; Casanoves, Fernando; Gibson, Kevin; Benjamin, Tamara J

2014-04-01

497

Weed management practices affect the diversity and relative abundance of physic nut mites.  

PubMed

Crop management practices determine weed community, which in turn may influence patterns of diversity and abundance of associated arthropods. This study aimed to evaluate whether local weed management practices influence the diversity and relative abundance of phytophagous and predatory mites, as well as mites with undefined feeding habits-of the families Oribatidae and Acaridae-in a physic nut (Jatropha curcas L.) plantation subjected to (1) within-row herbicide spraying and between-row mowing; (2) within-row herbicide spraying and no between-row mowing; (3) within-row weeding and between-row mowing; (4) within-row weeding and no between-row mowing; and (5) unmanaged (control). The herbicide used was glyphosate. Herbicide treatments resulted in higher diversity and relative abundance of predatory mites and mites with undefined feeding habit on physic nut shrubs. This was probably due to the toxic effects of the herbicide on mites or to removal of weeds. Within-row herbicide spraying combined with between-row mowing was the treatment that most contributed to this effect. Our results show that within-row weeds harbor important species of predatory mites and mites with undefined feeding habit. However, the dynamics of such mites in the system can be changed according to the weed management practice applied. Among the predatory mites of the family Phytoseiidae Amblydromalus sp. was the most abundant, whereas Brevipalpus phoenicis was the most frequent phytophagous mite and an unidentified oribatid species was the most frequent mite with undefined feeding habit. PMID:25528451

de Sousa Saraiva, Althiéris; Sarmento, Renato A; Erasmo, Eduardo A L; Pedro-Neto, Marçal; de Souza, Danival José; Teodoro, Adenir V; Silva, Daniella G

2015-03-01

498

Experimental transmission of pospiviroid populations to weed species characteristic of potato and hop fields.  

PubMed

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 10(5) and 10(3) 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. PMID:17715233

Matousek, J; Orctová, L; Ptácek, J; Patzak, J; Dedic, P; Steger, G; Riesner, D

2007-11-01

499

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. PMID:17715233

Matoušek, J.; Orctová, L.; Ptá?ek, J.; Patzak, J.; D?di?, P.; Steger, G.; Riesner, D.

2007-01-01

500

Skylarks trade size and energy content in weed seeds to maximize total ingested lipid biomass.  

PubMed

The trade-off between forage quality and quantity has been particularly studied in herbivore organisms, but much less for seed eating animals, in particular seed-eating birds which constitute the bulk of wintering passerines in European farmlands. The skylark is one of the commonest farmland birds in winter, mainly feeding on seeds. We focus on weed seeds for conservation and management purposes. Weed seeds form the bulk of the diet of skylarks during winter period, and although this is still a matter for discussion, weed seed predation by granivorous has been suggested as an alternative to herbicides used to regulate weed populations in arable crops. Our objectives were to identify whether weed seed traits govern foraging decisions of skylarks, and to characterize key seed traits with respect to size, which is related to searching and handling time, and lipid content, which is essential for migratory birds. We combined a single-offer experiment and a multiple-offer one to test for feeding preferences of the birds by estimating seed intake on weed seed species differing in their seed size and seed lipid content. Our results showed (1) a selective preference for smaller seeds above a threshold of seed size or seed size difference in the pair and, (2) a significant effect of seed lipid biomass suggesting a trade-off between foraging for smaller seeds and selecting seeds rich in lipids. Skylarks foraging decision thus seems to be mainly based on seed size, that is presumably a 'proxy' for weed seed energy content. However, there are clearly many possible combinations of morphological and physiological traits that must play crucial role in the plant-bird interaction such as toxic compound or seed coat. PMID:25452078

Gaba, Sabrina; Collas, Claire; Powolny, Thibaut; Bretagnolle, François; Bretagnolle, Vincent

2014-10-01