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1

Weed ManagementWeed ManagementWeed ManagementWeed ManagementWeed Management Purdue Extension  

E-print Network

WS-28-W Weed ManagementWeed ManagementWeed ManagementWeed ManagementWeed Management Purdue Educator Glenn R. W. Nice Purdue Extension Weed Professional Thomas Bauman Purdue Extension Weed Specialist Case R. Medlin Former Purdue Extension Weed Specialist In recent years, applications of herbi

2

Weed ManagementWeed ManagementWeed ManagementWeed ManagementWeed Management Purdue Extension  

E-print Network

Weed ManagementWeed ManagementWeed ManagementWeed ManagementWeed Management Purdue Extension WS-11-W Weed Management in Alfalfa Stands Dr. Case R. Medlin Assistant Professor of Weed Science Purdue University Steven D. Siegelin Adams County Extension Educator Purdue Extension Weed infestations can reduce

Holland, Jeffrey

3

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

4

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.

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

Weed Biotypes Weed Management in Grain  

E-print Network

Weed Biotypes Weed Management in Grain Sorghum--New for 2012 Huskie Herbicide #12;2012 Sorghum, Extension weed scientist, Lubbock, (806) 746-6101, pdotray@ag.tamu.edu Central Texas Paul Baumann, Extension weed scientist, College Station, (9797) 845-3041, pbaumann@ag.tamu.edu #12;Huskie Herbicide for GS

Behmer, Spencer T.

7

Green Weeding  

ERIC Educational Resources Information Center

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

Penniman, Sarah; McColl, Lisa

2008-01-01

8

Weed Management and Identification  

Microsoft Academic Search

Understanding the ecological relationships that underlie the interactions between weeds and cranberries is critical for successful weed management. In addition, versatility in correctly identifying the predominant weeds on a commercial bog is also essential. This paper discusses the place of weeds as part of an ecological framework that enables us to think about the present state and the future development

Hilary A. Sandler

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

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

11

Introduction to Weeds and Herbicides  

E-print Network

Introduction to Weeds and Herbicides #12;2 There are numerous definitions of a weed. Some common, weeds are plants whose undesirable qualities outweigh their good points, at least according to humans. Human activities create weed problems since no plant is a weed in nature. Though we may try

Kaye, Jason P.

12

Invasive Weed Outreach in Earl Creech  

E-print Network

1 Invasive Weed Outreach in Nevada Earl Creech Extension Weed Specialist Cache Valley, Utah 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

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

E-print Network

Weed Management Costs, Weed Best Management Practices, and The Roundup Ready® Weed Management Costs, Weed Best Management Practices, and The Roundup Ready® Weed Management Program T.M. Hurley Tucson, AZ Abstract Roundup ready (RR) crops have been widely adopted because they provide significant

Mitchell, Paul D.

14

WeedControl WEED CONTROL IN FLUE-CUREDTOBACCO  

E-print Network

37 WeedControl WEED CONTROL IN FLUE-CUREDTOBACCO Charles S. Johnson, Extension Plant Pathologist, Tobacco Good weed control uses crop rotation, early root and stalk destruction, cultivation-the-top at transplanting (OT) will reduce reliance on the first cultivation for early-season weed control. The number

Liskiewicz, Maciej

15

AQUATIC WEED CONTROL SPRING 2013  

E-print Network

PLS 4613 AQUATIC WEED CONTROL SPRING 2013 CREDITS: 3.0 DESCRIPTION: Identification of Florida's aquatic weed problems and methods of chemical, biological, mechanical and physical weed control. Specific, insect biocontrol, grass carp, and current laws regulating aquatic weed control. INSTRUCTOR: William T

Watson, Craig A.

16

SUGGESTIONS FOR WEED CONTROL IN  

E-print Network

B-5038 10-98 SUGGESTIONS FOR WEED CONTROL IN PASTURES AND FORAGES Texas Agricultural Extension;4 Suggestions for Weed Control in Pastures and Forages Dr. Paul A. Baumann, Extension Weed Specialist Dr. David as a guide for controlling weeds in pasture and forages. Labeled rates and restrictions change constantly

Mukhtar, Saqib

17

Tolerance of Crops and Susceptibility of Weeds  

E-print Network

Guide to Tolerance of Crops and Susceptibility of Weeds to Herbicides Bernard Zandstra and Michael . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 List of Weeds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Weed Control Ratings for each Herbicide

18

Genomics for Weed Science  

PubMed Central

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

Horvath, David

2010-01-01

19

7 CFR 201.15 - Weed seeds.  

Code of Federal Regulations, 2010 CFR

...Labeling Agricultural Seeds § 201.15 Weed seeds. The percentage of weed seeds shall include seeds of plants considered weeds in the State into which the seed...transported and shall include noxious weed seeds. [5 FR 31, Jan. 4,...

2010-01-01

20

Weed Identification Websites University of Florida Weed Science: http://weedext.ifas.ufl.edu/  

E-print Network

Weed Identification Websites · University of Florida Weed Science: http University Weed Science: http://www.weeds.iastate.edu/weedid/weedid.htm · Rutgers University New Jersey Weed Gallery: http://njaes.rutgers.edu/weeds · Virginia Tech Weed Identification Guide: http

Jawitz, James W.

21

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

22

Modelling for precision weed management.  

PubMed

Recently, the need for the development of weed management systems with a reduced dependency on herbicides has increased because of concern about environmental side-effects and cost. The development of such systems requires new strategies based on improvements with respect to (1) prevention, (2) decision making and (3) weed control technology. For the development of improvements in all three aspects, quantitative understanding of weed population dynamics and crop-weed interactions is needed. Models that integrate the available quantitative knowledge can be used to design preventive measures, to develop long-term and short-term strategies for weed management, to assist in decision making to determine if, when, where and how weeds should be controlled and to identify new opportunities for weed control. Ecophysiological simulation models for crop-weed competition simulate growth and production of species in mixtures, based on ecophysiological processes in plants and their response to the environment. Such models help improve insight into the crop-weed system and can be used for purposes such as the development of simple predictive yield-loss models, threshold levels or the design of competitive crop plant types. For strategic weed management decisions, preventive measures and the identification of new opportunities for weed control, quantitative insight into the dynamics and spatial patterns of weed populations is also required. The complexity of the process and the long-term character of weed population dynamics make the use of models necessary. Different modelling approaches have been developed and are described briefly. Opportunities to use the available knowledge and models to improve weed management are discussed. Weeds occur in patches and their sensitivity to herbicides changes strongly with developmental stage, making precision techniques for herbicide application in time and space an option for reducing herbicide use. Limitations related to insight in biological processes as well as the state of technological development are discussed. PMID:9573477

Kropff, M J; Wallinga, J; Lotz, L A

1997-01-01

23

www.btny.purdue.edu/weedscience/ Noxious and Invasive Weeds and The Weed  

E-print Network

weeds in these groups. If you would like to read the Indiana Code yourself or you have trouble sleeping technology available today. Restricted noxious weed seed are is from weeds GlennNice Purdue Extension Weed

24

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

25

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

26

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.

27

Weed Identification and Control in Vegetable Crops.  

ERIC Educational Resources Information Center

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

Ferretti, Peter A., Comp.

28

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 things you can do to reduce the economic impact of weeds. A healthy pasture has fewer weed problems. Soil to maintain a weed free pasture. Always use certi- fied seed to establish pastures and hay fields. Clean

Jawitz, James W.

29

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

E-print Network

296 · 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-term effect of agricultural management systems on weed communities will aid in developing sustainable weed

Sims, Gerald K.

30

PRINCIPLES OF WEED SCIENCE -PLS 4601c INTEGRATED WEED MANAGEMENT PLS 5632c  

E-print Network

1 PRINCIPLES OF WEED SCIENCE - PLS 4601c INTEGRATED WEED MANAGEMENT ­ PLS 5632c Department Description: An introduction to the principles of weed science. Lecture topics will include: weed biology and ecology, an introduction to weed management techniques and methodologies, factors affecting weed control

Watson, Craig A.

31

558 Weed Science 54, MayJune 2006 Weed Science, 54:558565. 2006  

E-print Network

558 · Weed Science 54, May­June 2006 Weed Science, 54:558­565. 2006 Symposium When does it make sense to target the weed seed bank? Adam S. Davis Corresponding author: USDA-ARS Invasive Weeds Management Unit, Urbana, IL 61801; asdavis1@uiuc.edu Weed seeds initiate most weed invasions of arable fields

Sims, Gerald K.

32

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

33

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

34

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

35

7 CFR 201.15 - Weed seeds.  

... 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

Managing Weeds in Potato Rotations Without Herbicides  

Microsoft Academic Search

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

Rick A. Boydston

2010-01-01

37

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

38

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

39

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.

40

Predominant rice weeds in Nigeria  

Microsoft Academic Search

In a survey conducted in the four major rice ecological zones in Nigeria the predominant weeds of the flora growing in association with both direct?seeded and transplanted rice (Oryza sativa L.) were determined. Most of the predominant weed species differed with differing rice ecologies. Among the predominant broadleaved species, Ageratum conyzoides L., Sphenochlea zeylanica Gaertn, Tridax procumbens L., Portulaca oleracea

L. I. Okafor

1986-01-01

41

62 Weed Science 53, JanuaryFebruary 2005 Weed Science, 53:6268. 2005  

E-print Network

62 · Weed Science 53, January­February 2005 Weed Science, 53:62­68. 2005 Duration of volunteer States Department of Agriculture­Agricultural Research Service, Invasive Weed Management Research research with annual weed species indicates that critical timing of weed removal begins primarily after

Sims, Gerald K.

42

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.

43

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

44

Managing arable weeds for biodiversity.  

PubMed

As a result of the recent intensification of crop production, the abundance and diversity of UK arable weeds adapted to cultivated land have declined, with an associated reduction in farmland birds. A number of questions need to be addressed when considering how these declines can be reversed. Firstly, can the delivery of crop production and biodiversity be reconciled by spatially separating cropping from designated wildlife areas? A number of subsidised environmental schemes in the UK take this approach and are focused on establishing vegetation cover on uncropped land. However, because of the lack of regular disturbance in these habitats, they are dominated by perennials and they therefore have limited potential for promoting the recovery of annual weed populations. A number of farmland bird species also rely on the provision of resources in field centres, and it is therefore likely that the recovery of their populations will rely on weed management options targeted at the cropped areas of the field. This raises two further questions. Firstly, is it possible to identify beneficial weed species that are relatively poor competitors with the crop and also have biodiversity value? Secondly, are the tools available to manage these species at acceptable levels while controlling pernicious weeds? A number of approaches are being employed to answer these questions, including predicting yield loss from weed competition models and exploiting herbicide selectivity. The further development of these tools is crucial if farmer opposition to managing weeds in crops is to be overcome. PMID:17437252

Storkey, Jonathan; Westbury, Duncan B

2007-06-01

45

Biology of weed pollen allergens.  

PubMed

Weeds represent a heterogeneous group of plants, usually defined by no commercial or aesthetic value. Important allergenic weeds belong to the plant families Asteraceae, Amaranthaceae, Urticaceae, Euphorbiaceae, and Plantaginaceae. Major allergens from ragweed, mugwort, feverfew, pellitory, goosefoot, Russian thistle, plantain, and Mercurialis pollen have been characterized to varying degrees. Four major families of proteins seem to be the major cause of allergic reactions to weed pollen: the ragweed Amb a 1 family of pectate lyases; the defensin-like Art v 1 family from mugwort, feverfew, and probably also from sunflower; the Ole e 1-like allergens Pla l 1 from plantain and Che a 1 from goosefoot; and the nonspecific lipid transfer proteins Par j 1 and Par j 2 from pellitory. As described for other pollens, weed pollen also contains the panallergens profilin and calcium-binding proteins, which are responsible for extensive cross-reactivity among pollen-sensitized patients. PMID:15283880

Gadermaier, Gabriele; Dedic, Azra; Obermeyer, Gerhard; Frank, Susanne; Himly, Martin; Ferreira, Fatima

2004-09-01

46

Detection and Identification of Weeds  

Microsoft Academic Search

\\u000a This chapter reviews the approaches for the automation of weed detection. Site-specific plant protection needs to address\\u000a the varying weed infestation, but the automation is only partially solved and research is still ongoing. The properties for\\u000a plant species distinction as well as approaches that use them are presented. The focus is on image based methods, of which\\u000a an example is

Martin Weis; Markus Sökefeld

47

2010 Pulse Weed Control Studies Brian Jenks and Ed Davis  

E-print Network

1 2010 Pulse Weed Control Studies Brian Jenks and Ed Davis NDSU and MSU Clearfield lentil weed......................................................... 15 Effect of Sharpen and Aim on weed control with Glyphosate............................................ 16 Effect of Sharpen and Aim on weed control with Glyphosate

Maxwell, Bruce D.

48

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

49

Weed Detection utilizing Quadratic Polynomial and ROI Techniques  

Microsoft Academic Search

Machine vision for selective weeding or selective herbicide spraying relies substantially on the ability of the system to analyze weed images and process the extracted knowledge for decision making prior to implementing the identified control action. To control weed, different weed type would require different herbicide formulation. Consequently the weed must be identified and classified accordingly. In this work, weed

A. J. Ishak; S. S. Mokri; M. M. Mustafa; A. Hussain

2007-01-01

50

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

E-print Network

94 · Weed Science 54, January­February 2006 Weed Science, 54:94­99. 2006 Volunteer potato­Agricultural Research Service, Invasive Weed Management Research, University of Illinois, 1102 S. Goodwin Ave., Urbana Research Service, Vegetable and Forage Crops Research, Prosser, WA 99350 Weed management systems in carrot

Sims, Gerald K.

51

930 Weed Science 51, NovemberDecember 2003 Weed Science, 51:930939. 2003  

E-print Network

930 · Weed Science 51, November­December 2003 Weed Science, 51:930­939. 2003 Cropping system Department of Agronomy, Iowa State University, Ames, IA 50011 Cropping system characteristics affect weed management by altering key demograph- ic rates of weeds, including recruitment, seedling survival, fecundity

Sims, Gerald K.

52

928 Weed Science 54, SeptemberOctober 2006 Weed Science, 54:928933. 2006  

E-print Network

928 · Weed Science 54, September­October 2006 Weed Science, 54:928­933. 2006 Planting date influences critical period of weed control in sweet corn Martin M. Williams II Corresponding author. U.S. Department of Agriculture--Agricultural Research Service, Invasive Weed Management Research, University

Sims, Gerald K.

53

838 Weed Science 54, SeptemberOctober 2006 Weed Science, 54:838846. 2006  

E-print Network

838 · Weed Science 54, September­October 2006 Weed Science, 54:838­846. 2006 Modeling site the landscape and may facilitate better timing of weed control where residue is present. Emergence of wild oat to improving prediction of weed seedling emergence. Nomenclature: Wild oat, Avena fatua L., AVEFA; winter wheat

Zhang, Hao

54

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

E-print Network

902 · Weed Science 53, November­December 2005 Weed Science, 53:902­908. 2005 Symposium Manipulating habitats dominated by a few plant species where pesticides play a major role in managing weed and insect by manipulating plant species and communities to benefit natural enemies of insects and weeds. Such efforts aim

Landis, Doug

55

368 Weed Science 53, MayJune 2005 Weed Science, 53:368. 2005  

E-print Network

368 · Weed Science 53, May­June 2005 Weed Science, 53:368. 2005 Symposium Introduction to the symposium Beyond thresholds: applying multiple tactics within integrated weed management systems More than specialists, integrated weed management (IWM) remains elusive in practice. Most definitions of IWM have two

Sims, Gerald K.

56

Suggestions for Weed Control in Peanuts  

E-print Network

Complete instructions for controlling weeds in peanuts are included in this publication. Tables suggest treatments for specific weeds during preplant and postemergence stages, and list common and chemical names of herbicides. Sprayer calibration...

Baumann, Paul A.; Lemon, Robert G.

2001-05-10

57

Sorghum Allelopathy for Weed Management in Wheat  

Microsoft Academic Search

Weeds cause substantial decline in agricultural production. To overcome weed infestation modern agricultural practices adopted\\u000a heavy use of a large variety of herbicides. With rising human health and ecological concerns about the adverse effects of\\u000a indiscriminate use of farm chemicals research on alternative weed management methods is underway worldwide. Exploitation of\\u000a allelopathic potential of different crop\\/plant species for weed management

Zahid A. Cheema; Abdul Khaliq; Muhammad Farooq

58

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

59

Weed Emergence Patterns and the Effect of Time of Weed Removal, with  

E-print Network

in Corn in 2006 Trt Herbicide1 Post Application Stage Cost 1 Harness / Roundup WeatherMAX + AMS 1" Weeds 37.75 2 Roundup WeatherMAX + AMS 1" Weeds 17.85 3 Harness / Roundup WeatherMAX + AMS 3" Weeds 37.75 4 Roundup WeatherMAX + AMS 3" Weeds 17.85 5 Harness / Roundup WeatherMAX + AMS 5" Weeds 37.75 6 Roundup

Minnesota, University of

60

Extension/Research Professor of Weed Science  

E-print Network

John Byrd Extension/Research Professor of Weed Science Box 9555 Mississippi State, MS 39762 662 excellent weed exterminators. Kerosene or waste oil from garages..." · "...oils of this kind should feet would seem a fair estimate." #12;Sulfuric Acid Spray: A practical means for the control of weeds

Watson, Craig A.

61

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.

62

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

63

HOME GROUNDS & ANIMALS 2014 5-8 Lawn: Weeds  

E-print Network

HOME GROUNDS & ANIMALS 2014 5-8 Lawn: Weeds Weeds Shawn D. Askew, Associate Professor, Virginia Tech Overview The first step in any lawn weed management program is to identify the problem. What grass kills seedling weeds and prevents large weed stands, which tend to decrease lawn aesthetics

Liskiewicz, Maciej

64

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

65

Weed Identification: Using Plant Structures as a Key (Spanish)  

E-print Network

Weed identification is necessary to the success of any weed control program. Frequently, simple plant keys or "picture book identification guides are used to identify weeds. This handbook, which identifies and labels plant structures, is intended...

Baumann, Paul A.

1999-08-30

66

Revised 1/09 PLANT / WEED IDENTIFICATION AND CONTROL  

E-print Network

Revised 1/09 PLANT / WEED IDENTIFICATION AND CONTROL Items with * must be completed for control ____________________ Date submitted ___________________ Mail report (No email) PLANT OR WEED INFORMATION. Items with * must ______________________________ rate ____________________________when__________________________ none used unknown 6. If weed

Duchowski, Andrew T.

67

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

68

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

E-print Network

2/21/2012 2012 CWSS UC Davis Weed Science 1 Brad Hanson, Tom Lanini, and Lynn Sosnoskie, UC Davis Weed Science bhanson@ucdavis.edu Cuttings first brought to North America from France in 1856 floors are managed for a number of reasons Facilitate crop production and harvest practices Weed

Hanson, Brad

69

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...

70

Control of Weeds in Rice Fields.  

E-print Network

. With the chief eource of twed seed eliminated, thc problem of weed control becomes less Zifficult. In addition to the elimination of weeds the broad, sloping levee has several other features to recommend its use. Plowing and other field operations may be done.... With the chief eource of twed seed eliminated, thc problem of weed control becomes less Zifficult. In addition to the elimination of weeds the broad, sloping levee has several other features to recommend its use. Plowing and other field operations may be done...

Laude, H. H. (Hilmer Henry)

1918-01-01

71

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

72

Herbicide options for weed control in papaya  

Microsoft Academic Search

This paper reviews the literature on weeds and weed control in papaya. There is limited research on this topic, and nearly all of the research focuses on herbicides. Effective use of paraquat and glyphosate in papaya is dependent on avoidance of spray contact to green bark and foliage. Pre-emergence herbicide tolerance is dependent on papaya age, size and maturity, and

R. K. NISHIMOTO

1997-01-01

73

Management of insect pests and weeds  

Microsoft Academic Search

The Cuban government has undertaken the task of transforming insect pest and weed management from conventional to organic and more sustainable approaches on a nationwide basis. This paper addresses past programs and current major areas of research and implementation as well as provides examples of programs in insect and weed management. Topics covered include the newly constructed network of Centers

Jeff Dlott; Ivette Perfecto; Peter Rosset; Larry Burkham; Julio Monterrey; John Vandermeer

1993-01-01

74

Why herbicides fail Extension Weed Specialist  

E-print Network

. More time for the plant to break down the herbicide. Cuticle thickness. #12;Adjuvants · Can greatly improve herbicide uptake #12;Leaf Surface No adjuvant adjuvant Reduction of Droplet Surface Tension #12Why herbicides fail J. Ferrell Extension Weed Specialist and Greg MacDonald Weed Scientist #12

Watson, Craig A.

75

Roundup Resistant Weeds Changing Weedscapes of Minnesota  

E-print Network

species - e.g. Giant foxtail, mustards, kochia - Non-residual herbicides -> warm species - e.g. Crabgrass you face in the non- GMO world #12;Herbicide Resistant Weed-History · The first identified herbicide in a sugarcane field in Hawaii. · Since then, more than 200 weeds resistant to one or more herbicides have been

Minnesota, University of

76

Weed control in tomato seedbeds  

E-print Network

damage to tomatoes and sweet potatoes. Sawyer? Daiiyn an& Co'ter (21) reported wood ccntrol in potatoes with estrin Vapane although not prfnerily a herbXcidex has been reported to kill several weeds (3) ~ In a sixsxery of' research results (3... nanner different to those used by carlscsx (9)x cxeb- tzee and Laiffler (10), Dallynx Sawyer snd Seif (11)x Dsnielscxx (13) ~ snd !8mges (19) ~ Vapast has been used by a nuaber of warksxe (3) to sterilise scd. l well in advance of' plxsxting...

Leeper, Paul W

2012-06-07

77

Nevada's Noxious Weed Program Nevada Department of Agriculture  

E-print Network

*Washoe Valley *West Central Lyon County *White River Valley *Groups organized as Cooperative Weed Management Areas (CWMA) Nevada Weed Control Districts (Active) Churchill County (GID) Diamond Valley DouglasNevada's Noxious Weed Program Nevada Department of Agriculture Dawn Rafferty, State Weed Program

Nowak, Robert S.

78

Weed Control Efficacy With Ammonium Nonanoate for Organic Vegetable Production  

Microsoft Academic Search

Organic Producers Rank Weed Management Research as their top priority. Organic vegetable producers have many challenges because their weed control tools are mostly limited to cultural methods, with a strong dependence on excessive tillage, cultivation, and hand-hoeing for weed control. Very few chemical weed control options have been approved for organic use. Racer®, ammonium nonanoate, is a new contact herbicide

Charles L. Webber III; James W. Shrefler; Lynn P. Brandenberger; Merritt J. Taylor; Lynda K. Carrier; D. Kent Shannon

2010-01-01

79

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

80

Aquatic Weeds in African Man-Made Lakes  

Microsoft Academic Search

There is a pattern of succession of weeds in man-made African lakes. Each phase of succession differs in each lake depending on the local environment. Floating weeds develop first, followed by sudd, a later decrease in floating weeds, an increase in submerged weeds, and finally an emergent drawdown flora. The stages in this sequence may be very pronounced in some

J. J. Gaudet

1979-01-01

81

Weed Biology and Management 5, 6976 (2005) RESEARCH PAPER  

E-print Network

Weed Biology and Management 5, 69­76 (2005) RESEARCH PAPER Weed composition and cover after three, could lead to increased weed problems for agricultural production. This experiment was conducted to assess weed pressure and species composition on plots receiving various inorganic and organic soil

Lehmann, Johannes

82

Jill Schroeder Professor, Entomology, Plant Pathology, and Weed Science,  

E-print Network

Jill Schroeder Professor, Entomology, Plant Pathology, and Weed Science, New Mexico State@nmsu.edu Education 1985 Ph.D. Department of Agronomy (Weed Science), University of Georgia, Athens, GA 1981 M, and Professor of Weed Science Department of Entomology, Plant Pathology, and Weed Science, NMSU Primary Research

Johnson, Eric E.

83

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

84

CONTROL OF HAIRY FLEABANE AND OTHER PROBLEM WEEDS IN  

E-print Network

2/21/2012 1 CONTROL OF HAIRY FLEABANE AND OTHER PROBLEM WEEDS IN PEACH ORCHARDS Brad Hanson Cooperative Extension Weed Specialist December 13, 2011 NSJV Cling Peach Day Modesto, CA What do we spend on weed control? 2009 cost study ­ Day et al. (fresh mkt peach) Annual costs for weed mgt $74 ­ winter

Hanson, Brad

85

Noxious Weed Survey of Peterson Air Force Base October 31, 2003  

E-print Network

Noxious Weed Survey of Peterson Air Force Base October 31, 2003 Prepared For: Peterson Air Force WEED STATUS BY SPECIES .................................................................................................. 17 APPENDIX 1: NOXIOUS WEED MAPS

86

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

87

Contrasting weed species composition in perennial alfalfas and six annual crops: implications for integrated weed management  

Microsoft Academic Search

Weed communities are most strongly affected by the characteristics and management of the current crop. Crop rotation may thus\\u000a be used to prevent the repeated selection of particular weed species. While weed communities are frequently compared among\\u000a annual crops, little is known about the differences between annual and perennial crops that may be included in the rotations.\\u000a Moreover, nearly all

Helmut Meiss; Safia Médiène; Rainer Waldhardt; Jacques Caneill; Nicolas Munier-Jolain

2010-01-01

88

Weed Detection Based on the Optimized Segmentation Line of Crop and Weed  

Microsoft Academic Search

Weed detection is a key problem of spot spraying that could reduce the herbicide usage. Spectral information of plants is\\u000a very useful to detect weeds in real-time for the fast response time. However, the cost of an imaging spectrograph-based weed\\u000a detection system is too high. Therefore, the main objective of this study was to explore a method to classify crop

Wenhua Mao; Xiaoan Hu; Xiaochao Zhang

2007-01-01

89

Bio-Gas Production from Alligator Weeds.  

National Technical Information Service (NTIS)

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 (Alternanth...

A. Latif

1976-01-01

90

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

91

Wild and Weed Azuki Beans in Japan  

Microsoft Academic Search

Wild azuki bean, a progenitor of an Asiatic food legume (Vigna angularis var.nipponensis: Fabaceae), and its weed form are distributed widely in the Japanese Archipelago. The straggling or climbing wildform occurs\\u000a in sleeve or mantle plant communities, and the weakly climbing or bushy weed form is found in relatively open human-disturbed\\u000a habitats. The wild form has small seeds with a

Hirofumi Yamaguchi

1992-01-01

92

Weed Control Research in Sugar Beets.  

E-print Network

in 1964. the Panhandle. : Ineffective weed control methods and high hoeing ' costs, excessive nitrogen fertilization, and leaf spot Preplant Incorporation I disease have created problems for sugar beet The effectiveness of preplant herbicides... beets are normally planted but worked well when applied in May. Pigweed control with Pyramin and Tillam increased as thoroughness of r incorporation increased. CP&592 and 852223 gave acceptable weed control, but development of these herbicides...

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

1975-01-01

93

Cultivation of Pleurotus ostreatus on weed plants.  

PubMed

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

Das, Nirmalendu; Mukherjee, Mina

2007-10-01

94

Weed Population Dynamics after Six Years under Glyphosate and Conventional Herbicide-based Weed Control Strategies  

Microsoft Academic Search

Field studies using glyphosate-resistant corn (Zea mays L.), sugarbeet (Beta vulgaris L.), and spring wheat (Triticum aestivum L.) were con- ducted at Scottsbluff, NE, Torrington, WY, and Fort Collins, CO, over 6 yr to evaluate weed population dynamics under glyphosate- and conventional herbicide-based weed control strategies. We report the response of common lambsquarters (Chenopodium album L.), wild buckwheat (Polygonum convolvulus

Philip Westra; Robert G. Wilson; Stephen D. Miller; Phillip W. Stahlman; Gail W. Wicks; Phillip L. Chapman; John Withrow; David Legg; Craig Alford; Todd A. Gaines

2008-01-01

95

Weed seed production, crop planting pattern, and mechanical weeding in wheat  

Microsoft Academic Search

Experiments were carried out to investigate weed seed production in widely spaced spring wheat crops that received aggressive mechanical weed control (hoeing and harrowing) compared with that in narrowly spaced crops receiving less aggressive mechanical control (harrowing only). Three species (wild buckwheat [Polygonum convolvulus], ladysthumb [Polygonum persicaria], and common chickweed [Stellaria media]) were studied in three row-spacing treatments (10, 20,

Shana K. Mertens

2002-01-01

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

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 in Greenhouses Jeffrey F. Derr, Extension Weed Scientist, Hampton Roads AREC Nonchemical Control Hand-weeding and good sanitation are the safest ways to control weeds in greenhouses. remove weeds from plugs or liners

Liskiewicz, Maciej

98

Texas High Plains Vegetable & Weed Control Research Program  

E-print Network

RESULTS OF HIGH PLAINS TRIALS 8 Herbicides and Weed Control Herbicide screen for mustard and collard greens ......................................................................... 9 Selected herbicides of selected herbicides for weed control and injury in yellow squash .................................. 13

Mukhtar, Saqib

99

Table 1. Summary of weed seedbank distribution, diversity (number of species per field) and density across all farms Unit Total Weeds Average Highest Lowest  

E-print Network

Table 1. Summary of weed seedbank distribution, diversity (number of species per field) and density across all farms Unit Total Weeds Average Highest Lowest Total Identified Weed Species number 67 13 21 5 Total Identified Weed Species Densityb no./ft 2 274 1081 30 Total Identified Broadleaf Weed Species

Hayden, Nancy J.

100

Weed Management in Rice?Based Cropping Systems in Africa  

Microsoft Academic Search

Weed competition is a major constraint in all the rice production systems in Africa. In addition to the costs of weed control, weeds account for yield losses estimated to be at least 2.2 million tons per year in sub?Saharan Africa, valued at $1.45 billion, and equating to approximately half the current total imports of rice to this region. Important weeds

J. Rodenburg; D. E. Johnson

2009-01-01

101

Research on crop and weed identification by NIR spectroscopy  

Microsoft Academic Search

Crop and weed identification is very importance in precision farming field. As spectroscopy can reflects the contents of object tested, so it is possible to identify crop and weed with high correct rate. ASD FieldSpec recorded the spectrum of crops and weeds. Its waveband is 325-1075nm and with resolution of 3.5nm. One crop seedling and three kinds of weeds living

Jiazhi Pan; Yueming Tang; Yong He

2007-01-01

102

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

103

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

104

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

105

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

106

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

107

Weeds of Central, Southern and Eastern Arabian Peninsula  

Microsoft Academic Search

A list of weeds of agricultural areas in the central, southern and eastern Arabian Peninsula is presented along with the maximum intensities of weed infestation resulting from these plants. Although each country studied or a region within a country has a particular set of weeds causing severe infestation, in general the species of greatest importance common to the whole of

S. A. Chaudhary; C. Parker; L. Kasasian

1981-01-01

108

Integrating Residual Herbicides into Corn and Soybean Weed Management  

E-print Network

Reduces: Increases: Weed density Increases yield potential Weed species diversity Herbicide/adjuvantIntegrating Residual Herbicides into Corn and Soybean Weed Management Plans Jeffrey L. Gunsolus lambsquarters. However, one difference is an increase in frequency of herbicide-resistance in all

Minnesota, University of

109

Weed Control in Field Crops Table of Contents  

E-print Network

Weed Control in Field Crops Table of Contents Chemical.........................................................................5-8 Herbicide site of action for reducing the risk of developing herbicide-resistant weeds...................................................................................5-43 Table 5.15 - Susceptibility of Pasture Weeds to Recommended Herbicide Treatments

Liskiewicz, Maciej

110

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 1999 Summary Data were analysed on weed biomass from untreated plots in 2672 ®eld experiments conducted) among years in the biomass of annual weeds per square metre was 29% in autumn-sown crops. In spring

Palmer, Michael W.

111

ORIGINAL PAPER Development and validation of a weed screening tool  

E-print Network

ORIGINAL PAPER Development and validation of a weed screening tool for the United States Anthony L 2011 Ã? Springer Science+Business Media B.V.(outside the USA) 2011 Abstract The Australian weed risk of weeds and invasive plants into new areas. On average, the Australian model identifies major

Schweik, Charles M.

112

Weeds Sampling for Map Reconstruction: a Markov Random Field Approach  

E-print Network

Weeds Sampling for Map Reconstruction: a Markov Random Field Approach M. Bonneau1,2 , S. Gaba2 , N In the past 15 years, there has been a growing interest for the study of the spatial repartition of weeds of these methods is that they are based on in situ collection of data about weeds spatial repartition. A crucial

Boyer, Edmond

113

Texas High Plains Vegetable & Weed Control Research Program  

E-print Network

Texas High Plains Vegetable & Weed Control Research Program Research Summary Reports 2006 Texas Experiment Station Russell W. Wallace Extension Vegetable & Weed Specialist Alisa K. Petty Research ................................................... 7 RESULTS OF HIGH PLAINS TRIALS 8 Herbicides and Weed Control Evaluation of Firestorm Applied

Mukhtar, Saqib

114

Weeds-wheat discrimination using hyperspectral imagery Xavier Hadoux1  

E-print Network

Weeds-wheat discrimination using hyperspectral imagery Xavier Hadoux1 *, Nathalie Gorretta1 between weeds and crop by computer vision remains today a major obstacle to the promotion of localized weeding practices. The objective of the present study was to evaluate the potential of hyperspectral

Paris-Sud XI, Université de

115

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

116

Practical advice for weeding in small academic libraries  

Microsoft Academic Search

Purpose – The purpose of this paper is to present information on how to organize and carry out a weeding project in an academic library. Design\\/methodology\\/approach – Describes how the weeding project was organized and its various phases. Findings – Argues that weeding is appropriate in small, academic non-research libraries and discusses a methodology for approaching it. Originality\\/value – Provides

Michael W. Handis

2007-01-01

117

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"

118

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

119

Weed Busters: How to Repel Rayless Goldenrod  

E-print Network

) Ingredient Solution 3 15 25 Tordon 22K? 1% 4 ounces 19 ounces 32 ounces Surfactant 1 /4%1 ounce 5 ounces 8 ounces Dye 1 /4%1 ounce 5 ounces 8 ounces All spray solutions are mixed in water. R ayless goldenrod, sometimes called jimmy- weed, is a noxious, toxic...) Ingredient Solution 3 15 25 Tordon 22K? 1% 4 ounces 19 ounces 32 ounces Surfactant 1 /4%1 ounce 5 ounces 8 ounces Dye 1 /4%1 ounce 5 ounces 8 ounces All spray solutions are mixed in water. R ayless goldenrod, sometimes called jimmy- weed, is a noxious, toxic...

2005-03-07

120

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

121

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

122

Weed hosts of cotton mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae).  

PubMed

The exotic cotton mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) invaded India during 2006, and caused widespread infestation across all nine cotton growing states. P. solenopsis also infested weeds that aided its faster spread and increased severity across cotton fields. Two year survey carried out to document host plants of P. solenopsis between 2008 and 2010 revealed 27, 83, 59 and 108 weeds belonging to 8, 18, 10 and 32 families serving as alternate hosts at North, Central, South and All India cotton growing zones, respectively. Plant species of four families viz., Asteraceae, Amaranthaceae, Malvaceae and Lamiaceae constituted almost 50% of the weed hosts. While 39 weed species supported P. solenopsis multiplication during the cotton season, 37 were hosts during off season. Higher number of weeds as off season hosts (17) outnumbering cotton season (13) at Central over other zones indicated the strong carryover of the pest aided by weeds between two cotton seasons. Six, two and seven weed hosts had the extreme severity of Grade 4 during cotton, off and cotton + off seasons, respectively. Higher number of weed hosts of P. solenopsis were located at roadside: South (12) > Central (8) > North (3) zones. Commonality of weed hosts was higher between C+S zones, while no weed host was common between N+S zones. Paper furnishes the wide range of weed hosts of P. solenopsis, discusses their significance, and formulated general and specific cultural management strategies for nationwide implementation to prevent its outbreaks. PMID:24620572

Vennila, S; Prasad, Y G; Prabhakar, M; Agarwal, Meenu; Sreedevi, G; Bambawale, O M

2013-03-01

123

Molecular Biology and Genomics: New Tools for Weed Science  

NSDL National Science Digital Library

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

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

2009-03-01

124

Weed Suppression by Seven Clover Species  

Microsoft Academic Search

Used as cover crops, clover species may differ in their ability to suppress weed growth. Field trials were conducted in Alberta, Canada to measure the growth of brown mustard [Brassica juncea (L.) Czern.], in mowed and nonmowed production, as influenced by alsike (Trifolium hybridum L.), balansa [T. michelianum Savi var. balansae (Boiss.) Azn.], berseem (T. alexandrinum L.), crimson [T. incarnatum

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

2001-01-01

125

Chloropicrin effect on weed seed viability  

Microsoft Academic Search

Chloropicrin is a potential replacement for methyl bromide as a preplant soil fumigant. Its weed control efficacy was evaluated in a laboratory dose–response study and in a commercial strawberry field. Laboratory studies found that an increase in chloropicrin concentration and exposure time reduced the percentage of viable Stellaria media (L.) Mill., Portulaca oleracea L. and Polygonum aviculare L. seed. Chloropicrin

M. J. Haar; S. A. Fennimore; H. A. Ajwa; C. Q Winterbottom

2003-01-01

126

Home Orchard Weed Control By Paul Vossen  

E-print Network

as it breaks down slowly, it creates a loose tilth to the soil, and it releases nutrients. Water absorption and retention is also aided. It can be expensive and labor intensive to spread, but well worth it. #12;2. Fabric water to pass through, but no weeds grow through it. You probably have seen it at container nurseries

California at Davis, University of

127

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

128

Jimson "Loco" Weed Abuse in Adolescents.  

ERIC Educational Resources Information Center

Over a 3-year period, 29 adolescent patients were hospitalized because of intentional Jimson weed ingestion. Their records were reviewed for the presence of signs and symptoms of atropine/scopolamine toxicity, clinical course, treatment, and outcome. Journal availability: Arthur Retlaw and Associates, Inc., Suite 2080, 1603 Orrington Avenue,…

Shervette, Robert E., III; And Others

1979-01-01

129

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.

130

IMPROVING SPORT FISHING of AQUATIC WEEDS  

E-print Network

BY CONTROL OF AQUATIC WEEDS By Eugene W. Surber Bureau of Sport Fisheries and Wildlife Atlanta, Georgia, Ft. Lauderdale, Florida; and Howard Zeller, Georgia Game and Fish Commission, Atlanta, read and Wildlife Atlanta, Georgia \\i INTRODUCTION The purpose of this leaflet is t

131

7 CFR 201.50 - Weed seed.  

Code of Federal Regulations, 2011 CFR

...structures classified as inert matter. (b) Wild onion and wild garlic (Allium spp.) bulblets that have any part of the husk...round-hole sieve are considered weed seeds. For wild onion and wild garlic (Allium spp.) bulblets classed as inert matter, refer...

2011-01-01

132

7 CFR 201.50 - Weed seed.  

Code of Federal Regulations, 2012 CFR

...structures classified as inert matter. (b) Wild onion and wild garlic (Allium spp.) bulblets that have any part of the husk...round-hole sieve are considered weed seeds. For wild onion and wild garlic (Allium spp.) bulblets classed as inert matter, refer...

2012-01-01

133

7 CFR 201.50 - Weed seed.  

Code of Federal Regulations, 2010 CFR

...structures classified as inert matter. (b) Wild onion and wild garlic (Allium spp.) bulblets that have any part of the husk...round-hole sieve are considered weed seeds. For wild onion and wild garlic (Allium spp.) bulblets classed as inert matter, refer...

2010-01-01

134

Sparse representation for weed seeds classification  

Microsoft Academic Search

In agricultural industry, there is a longing for highly efficient and reliable seeds classification methods. Fast implementation of the existing methods is of great economical importance. Almost all categories of weed seeds have different size, shape and texture, and even the same species are quantitatively diverse in feature. Therefore, feature extraction is a tough, time consuming and labor-intensive task. In

Ming Zhang; Cheng Cai; Junping Zhu

2010-01-01

135

HOME GROUNDS & ANIMALS 2014 Home Ornamentals: Weed Management in Home Ornamental Beds 4-89  

E-print Network

HOME GROUNDS & ANIMALS 2014 Home Ornamentals: Weed Management in Home Ornamental Beds 4-89 Weed Management in Home Ornamental Beds Jeffrey F. Derr, Extension Weed Scientist, Hampton Roads AREC Overview Weed management is necessary in flower beds and for shrub and tree plantings. Weeds reduce

Liskiewicz, Maciej

136

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

E-print Network

South Carolina Pest Management Handbook for Field Crops - 2014 262 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

Duchowski, Andrew T.

137

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.

138

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

139

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

E-print Network

Research Paper Design and testing of an intra-row mechanical weeding machine for corn C. Cordill As an alternative to chemical weed control, mechanical weed control between crop rows can be achieved using standard-row weed control in maize. The object was to non-specifically remove weed plants within the row by enabling

140

[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

141

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

142

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

143

Plant-Soil Interactions, Weed Control, and Rice Tolerance as Affected by Saflufenacil  

E-print Network

Saflufenacil is a new herbicide for broadleaf weed control. Limited information is available for crop tolerance, weed control and herbicide behavior in the rice environment. Studies were designed to 1 and 2) evaluate rice tolerance and weed control...

Camargo, Edinalvo

2012-10-19

144

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

145

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

146

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

147

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

Code of Federal Regulations, 2011 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...

2011-01-01

148

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

149

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

150

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

...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

151

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

...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

152

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

153

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

154

Feeding Preferences of Weed Seed Predators and Effect on Weed Emergence Sharon S. White, Karen A. Renner, Fabian D. Menalled, and Douglas A. Landis*  

E-print Network

Feeding Preferences of Weed Seed Predators and Effect on Weed Emergence Sharon S. White, Karen A predators and the effect of seed predation on weed emergence. Feeding choice studies were completed seed consumption did not differ between these two weed species. All invertebrates consumed fewer

Landis, Doug

155

Can Arbuscular Mycorrhizal Fungi Reduce the Growth of Agricultural Weeds?  

PubMed Central

Background Arbuscular mycorrhizal fungi (AMF) are known for their beneficial effects on plants. However, there is increasing evidence that some ruderal plants, including several agricultural weeds, respond negatively to AMF colonization. Here, we investigated the effect of AMF on the growth of individual weed species and on weed-crop interactions. Methodology/Principal Findings First, under controlled glasshouse conditions, we screened growth responses of nine weed species and three crops to a widespread AMF, Glomus intraradices. None of the weeds screened showed a significant positive mycorrhizal growth response and four weed species were significantly reduced by the AMF (growth responses between ?22 and ?35%). In a subsequent experiment, we selected three of the negatively responding weed species – Echinochloa crus-galli, Setaria viridis and Solanum nigrum – and analyzed their responses to a combination of three AMF (Glomus intraradices, Glomus mosseae and Glomus claroideum). Finally, we tested whether the presence of a crop (maize) enhanced the suppressive effect of AMF on weeds. We found that the growth of the three selected weed species was also reduced by a combination of AMF and that the presence of maize amplified the negative effect of AMF on the growth of E. crus-galli. Conclusions/Significance Our results show that AMF can negatively influence the growth of some weed species indicating that AMF have the potential to act as determinants of weed community structure. Furthermore, mycorrhizal weed growth reductions can be amplified in the presence of a crop. Previous studies have shown that AMF provide a number of beneficial ecosystem services. Taken together with our current results, the maintenance and promotion of AMF activity may thereby contribute to sustainable management of agroecosystems. However, in order to further the practical and ecological relevance of our findings, additional experiments should be performed under field conditions. PMID:22164216

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

2011-01-01

156

Evaluation of Neural-network Classifiers for Weed Species Discrimination  

Microsoft Academic Search

The potential environmental impact of herbicide utilisation has stimulated research into new methods of weed control. Selective herbicide application offers the possibility to reduce herbicide usage while maintaining weed control. The research reported utilised colour co-occurrence method (CCM) texture analysis techniques to evaluate three different neural-network classifiers for potential use in real-time weed control systems. An image data set consisting

T. F. Burks; S. A. Shearer; J. R. Heath; K. D. Donohue

2005-01-01

157

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

158

Suggestions for Weed Control in Sorghum  

E-print Network

.......................................... 11 The suggestions contained herein are based primarily on herbicide labels, research by the Texas Agricultural Experiment Station and demonstrations by the Texas Agricultural Extension Service. The use of product names is not intended... is implied. This publication is no substitute for the herbicide product labels! It is intended to serve only as a guide for controlling weeds in sorghum. Labeled rates and restrictions change constantly, therefore, consult the product label prior to use...

Baumann, Paul A.; Coffman, Cloyce G.

2001-05-04

159

Suggestions For Weed Control In Cotton  

E-print Network

by David Nace, page 20 photograph by Scott Bauer, both of the U.S. Department of Agriculture Suggestions for in Cotton Tables 1. Winter Weed Control Treatments ...............................................6 2. Preplant... inhibitor 8 lb/gal Syngenta Dual ? II Magnum metolachlor Long chain fatty acid inhibitor 7.8 lb/gal Syngenta DSMA DSMA Unknown 3.6 lb/gal UAP Envoke ? trifloxysulfuron Acetolactate synthase (ALS, AHAS) inhibitor 75 WG Syngenta Fusilade ? DX fluazifop...

Baumann, Paul A.; Lemon, Robert G.

2007-07-03

160

Allelopathic aquatic plants for aquatic weed management  

Microsoft Academic Search

This report presents, results of a feasibility study of use of allelopathic aquatic plants for aquatic weed management. In\\u000a order to establish a list of potential allelopathic plants, we selected 16 aquatic plants native to the southeastern United\\u000a States and subjected them to two bioassays — one involving lettuce seedlings and one involving the aquatic plantLemna minor as the target

Stella D. Elakovich

1989-01-01

161

Influence of mulches for weed control in the landscape  

E-print Network

, sawdust, or crushed corn cobe gave more effective control than a shallow mulch (5cm) of the same material (Gartner, 1978). Campbell-Lloyd (1986) states that provided a 7. 5cm layer of bark mulch is properly applied, 854 weed control should be achieved... and sewage sludge) can break down rapidly and be re-invaded quickly by weeds (Insley, 1981). Finely, pulverized grades of bark, in particular, tend to be colonized rapidly (Campbell-Lloyd, 1986). Moreover, the weed problem may be increased by weed seed...

Billeaud, Lorraine Ann

2012-06-07

162

Herbicide-resistant weed management: focus on glyphosate.  

PubMed

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

Beckie, Hugh J

2011-09-01

163

Activity of mesotrione on resistant weeds in maize.  

PubMed

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

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

2002-09-01

164

ORIGINAL PAPER Weed seeds as nutritional resources for soil Ascomycota  

E-print Network

-borne microorganisms. In this study, we investigated seeds of four common broadleaf weeds, velvetleaf (Abutilon theophrasti), woolly cupgrass (Eriochloa villosa), Pennsyl- vania smartweed (Polygonum pensylvanicum

Sims, Gerald K.

165

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

166

Ability of weeds to host the root lesion nematodes Pratylenchus neglectus and P. thornei I. Grass weeds  

Microsoft Academic Search

Nine grass weed species common to cropping rotations in southern Australia were assessed as hosts of the root lesion nematodes,\\u000a Pratylenchus neglectus (Rensch) Filipjev Schuurmans & Stekhoven and P. thornei Sher & Allen. Weeds were grown at 20°C and individual plants inoculated with 1000 P. neglectus or P. thornei. Weed species were classified as non-hosts, poor hosts or good hosts,

Vivien A. Vanstone; Michelle H. Russ

2001-01-01

167

Davis et al.: Weed seed mortality 291 Weed Science, 54:291297. 2006  

E-print Network

Sciences, Michigan State University, East Lansing, MI 48824. Current address: USDA-ARS Invasive Weeds, West Lafayette, IN 47907 Karen A. Renner Department of Crop and Soil Sciences, Michigan State) [giant foxtail ( 0.54, P 0.01) and velvetleaf ( 0.60, P 0.01)], suggesting that seeds of the two species

Sims, Gerald K.

168

Herbicide tolerance and weed control strategies for Lesquerella production  

Microsoft Academic Search

Lesquerella fendleri (Gray) Wats, has the potential of being an economical, water-efficient source of hydroxy fatty acid that is useful in the production of specialty lubricants, plastics, coatings, and cosmetics. Lesquerella's slow initial growth habit makes it noncompetitive with most weed species. This is especially true during the spring when the more aggressive summer weeds begin to appear. Because the

Richard J. Roseberg

1996-01-01

169

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.

170

Biological control of neotropical aquatic weeds with fungi  

Microsoft Academic Search

Many of the world's worst tropical aquatic weeds are native to the Neotropics. Besides, the majority of the most aggressive aquatic weeds in that vast region of the world are endemic and therefore there is a need for exploration for biological control agents in that area. Entomologists had an early lead on this search. Only in the late 1970s did

R Barreto; R Charudattan; A Pomella; R Hanada

2000-01-01

171

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

172

WEED CONTROL BPG NOTE 11 Best Practice Guidance  

E-print Network

WEED CONTROL BPG NOTE 11 Best Practice Guidance for Land Regeneration Introduction Weed control on what your strategy will be, and how intensive it should be, is based on a number of factors. I Type of tree chosen and area into which it is planted. Trees planted into more fertile land, for example well

173

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

174

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

175

Insecticides and Arable Weeds: Effects on Germination and Seedling Growth  

Microsoft Academic Search

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

M. E. Hanley; M. D. Whiting

2005-01-01

176

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

177

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

178

Ecological interpretation of weed flora dynamics under different tillage systems  

Microsoft Academic Search

In northern Italy, on soil managed with three different tillage systems (conventional tillage, ridge tillage, and no-tillage) and submitted to standard cultural practices (crop rotation, and chemical weed control), the weed vegetation was assessed at the beginning of the trial (1987) and after six, and eight years. The aims were to evaluate (1) the effect of tillage systems on the

Giuseppe Zanin; Stefan Otto; Lara Riello; Maurizio Borin

1997-01-01

179

RESEARCH ARTICLE Evidence for weed quantity as the major information  

E-print Network

environmental impacts. To this end, organic farming appears as a promising solution. How- ever organic farming. Therefore there is a need for improved decision support tools for weed management in organic farming a participatory approach. Keywords Weed management . Organic farming . Information . Decision-making . Dynamic

Paris-Sud XI, Université de

180

'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

181

Applying a weed risk assessment approach to GM crops.  

PubMed

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

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

2014-12-01

182

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

183

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

Microsoft Academic Search

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

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

2003-01-01

184

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

185

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 by shallow disking. Controls pigweed, ragweed and other broadleaf weeds. Use the higher rate for fields

Duchowski, Andrew T.

186

Effects of artificial shading and weed mowing in reforestation of Mediterranean abandoned cropland with contrasting  

E-print Network

Effects of artificial shading and weed mowing in reforestation of Mediterranean abandoned cropland, and weeds are strong competitors for resources, particularly water. We conducted a 3-year experiment of full-light versus artificial shading and weed presence versus weed mowing. We measured seedling

Espigares, Tíscar

187

United States Department of Agriculture-Agricultural Research Service research on pest biology: weeds  

Microsoft Academic Search

Over 125 permanent full-time scientists conduct research within the USDA Agricultural Research Service (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 on weed control and integrated crop and soil management. Describing all

Frank Forcella

2003-01-01

188

GESTINF: a decision model for post-emergence weed management in soybean ( Glycine max (L.) Merr.)  

Microsoft Academic Search

The selection of the best weed control option can be improved using decision-support systems considering the different factors affecting the efficacy (weed species, growth stage, climatic conditions) and the economics of the treatments. An interactive microcomputer program called GESTINF has been developed to assist in the selection of weed control options in soybean and winter wheat. Using observed weed densities,

A. Berti; G. Zanin

1997-01-01

189

Combinations of Microbial and Insect Biocontrol Agents for Management of Weed Seeds  

Microsoft Academic Search

Important roles for biotic agents in integrated weed management include preventing seed production and weed emergence from the seed bank. Seed-attacking microorganisms have been described for a limited number of economically important weeds and serve as examples illustrating the potential for reducing weed seed production. Innundative releas- es of seed-feeding insects have also successfully reduced viable seeds produced by spe-

R. J. KREMER

190

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.

191

Weed populations and agronomic practices at wheat farms on the Hanang plains in Tanzania  

Microsoft Academic Search

Weed species and densities of weeds present on the wheat farms at the Hanang plains in northern Tanzania were surveyed just before wheat harvest in May, 1986. The dominant weed was Setaria spp. mainly, Setaria verticillata (L.) Beauv., which occurred at an average density of 58 shoots\\/m. Additional weed species which occurred at average densities of greater than 1 plant\\/m

J. R. Moyer; Z. J. Owenya; S. P. Kibuwa

1989-01-01

192

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

E-print Network

Marshall, Extension Weed Specialist Preplant/Burndown Herbicides for Weed Management in Peanut Herbicide to specific label for weeds controlled, application rates, adjuvants, and precautions. GLYPHOSATE does/Burndown Herbicides for Weed Management in Peanut (cont) Herbicide Rate/Acre Broadcast Mode of Action Preharvest

Stuart, Steven J.

193

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

E-print Network

1 LRES 443 - WEED ECOLOGY & MANAGEMENT Instructor: Dr. Bruce Maxwell TA: Melissa Bridges Professor and understanding of the principles of weed science. 2. To develop an appreciation for adaptations that allow weeds and concepts associated with plant population and community ecology. 4. To develop an understanding of how weed

Maxwell, Bruce D.

194

Horticultural & Forest crops 2014 Grapes: Weed Control in Vineyards 3-19  

E-print Network

Horticultural & Forest crops 2014 Grapes: Weed Control in Vineyards 3-19 Weed Control in Vineyards Jeffrey F. Derr, Extension Weed Scientist, Hampton Roads AREC Table 3.5 - Herbicides Labeled for Use and postemergence herbicides can be made to control existing vegetation and control weeds germinating from seed

Liskiewicz, Maciej

195

Potential of 3D-weed density maps in Precision Matthias Backes and Lutz Plumer  

E-print Network

Potential of 3D-weed density maps in Precision Farming Matthias Backes and Lutz Pl¨umer Institute;pluemer)@ikg.uni-bonn.de WWW: http://www.ikg.uni-bonn.de Abstract. The exact knowledge about the spatial distribution of weeds weed maps derived from spatial sampling continuous threshold-based contours of weed patches or areas

Behnke, Sven

196

Weed Control 2008 Burley ToBacco ProducTion Guide  

E-print Network

Weed Control 2008 Burley ToBacco ProducTion Guide WEED CONTROL IN BURLEy TOBACCO Charles S. Johnson, Extension Plant Pathologist, Tobacco Good weed control uses crop rotation, early root destruction on the first cultivation for early-season weed control. Some herbicides may also be applied to the row mid- dle

Liskiewicz, Maciej

197

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

E-print Network

Managing Weeds in Lentils In recent years there has been increased interest in diversifying Montana and opportunities of managing weeds in these crops. Weed management in lentils is of particular importance vegetative growth. Yield loss from competition with weeds can range as high as 80 percent. Lentil's low

Maxwell, Bruce D.

198

Weed leaf recognition in complex natural scenes by model-guided edge Benoit De Mezzo1  

E-print Network

Weed leaf recognition in complex natural scenes by model-guided edge pairing Benoit De Mezzo1.demezzo@cemagref.fr ; gilles.rabatel@cemagref.fr ; fiorio@lirmm.fr Abstract New weeding strategies for pesticide reduction rely on the spatial distribution and characterisation of weed populations. For this purpose, weed identification can

Paris-Sud XI, Université de

199

South Carolina Pest Management Handbook for Field Crops -2013 WEED CONTRL IN FIELD CORN  

E-print Network

South Carolina Pest Management Handbook for Field Crops - 2013 17 WEED CONTRL IN FIELD CORN Mike Marshall, Extension Weed Specialist Preplant/Burndown Herbicides for Weed Management in Corn solution for weeds 3 inches or less in height. BALANCE FLEXX may be tank mixed with PARAQUAT, GLYPHOSATE

Stuart, Steven J.

200

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

E-print Network

South Carolina Pest Management Handbook for Field Crops - 2013 137 WEED CONTROL IN GRAIN SORGHUM Mike Marshall, Extension Weed Specialist Preplant/Burndown Herbicides for Weed Management in Grain and cutleaf evening primrose than GLYPHOSATE. Add NIS at 1 qt/100 gal of spray mix. Weed and Cover Crop

Stuart, Steven J.

201

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

E-print Network

Monthly Highlights from Rutgers New Jersey Agricultural Experiment Station January 2009 Weed in Weed Science and Jack Rabin, Associate Director - Farm Programs Continued on page 2 Let no weeds go to seeds. Farmers wanting to control weeds with non-chemical herbicide alternatives should

Goodman, Robert M.

202

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 by shallow disking. Controls pigweed, ragweed and other broadleaf weeds. Use the higher rate for fields

Stuart, Steven J.

203

(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 ___________________________________________________ _____________________________________________________________________________________________ Remember, weeds in tree rows are unwanted, but weeds in row middles can be beneficial as long as they do

Ishida, Yuko

204

Row spacing and weed control timing affect yield of aerobic rice  

Microsoft Academic Search

Field experiments were conducted during the wet season of 2009 and dry season of 2010 to determine the effects of row spacing and timing of weed control on weed growth and yield of aerobic rice. Ten weed management treatments were used to identify critical periods of weed competition with aerobic rice grown in three different row spacings (15-cm, 30-cm, and

Bhagirath S. Chauhan; David E. Johnson

2011-01-01

205

Influence of tillage systems on weed seedling emergence pattern in rainfed rice  

Microsoft Academic Search

Differences in weed seedling emergence patterns due to agronomic practices, such as tillage, have implications for weed competition and weed management strategies. The effect of different tillage systems, including conventional tillage, minimum tillage and zero-tillage, on the emergence pattern of different weed species was evaluated in a field experiment in the wet (rainfed) seasons of 2007 and 2008. In both

Bhagirath Singh Chauhan; David E. Johnson

2009-01-01

206

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

207

Effect on Weed Growth of Short-Term Cover over Organically Grown Carrots  

Microsoft Academic Search

The effect on weeds and crop yield of a short-term polypropylene cover as a protection against carrot fly (Psila rosae) damage to organically grown carrots was assessed. Crops were hand-weeded prior to cover and then subjected to one of three weeding treatments during the covered period: none, one or two weedings. Total weed weight was greater with covered, versus non-covered,

L. Peacock

1991-01-01

208

The Southern Weed Science Society Weed Contest was held on August 1, 2012 in Fayetteville, AR. This event is an educational experience for undergraduate and graduate students in Southern Universities to  

E-print Network

The Southern Weed Science Society Weed Contest was held on August 1, 2012 in Fayetteville, AR to broaden their applied skills in Weed Science. The contest consists of 5 parts which are weed identification, applicator calibration, herbicide identification by the response of various crops and weeds

Tennessee, University of

209

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

210

Noxious Weeds in the U.S. and Canada  

NSDL National Science Digital Library

This web site provides a searchable database of the noxious weed lists for all U.S. states and six southern provinces of Canada. The database can be searched by plant name, state name, or by clicking on a map. The search can be narrowed down to search for native, exotic, or all species of plants for a particular county. Furthermore, the search can be conducted for the time period that the user chooses. A summary of this database provides a list of all noxious weeds, which can be customized to display in alphabetical order (on scientific name) or by the number of appearances on weed lists.

2007-07-24

211

Assessment of phytotoxic action of Ageratum conyzoides L. (billy goat weed) on weeds  

Microsoft Academic Search

Ageratum conyzoides L. (billy goat weed), showed strong inhibition on Raphanus sativus L. (radish) germination and growth in a bioassay. The leaves exhibited a greater suppression than the stem and root. The leaves of A. conyzoides applied at 2tha?1 reduced about 70% of the growth of Echinochloa crus-galli var. formosensis Ohwi. and completely inhibited emergence of Monochoria vaginalis (Burm.f. Persil

Tran Dang Xuan; Tawata Shinkichi; Nguyen Huu Hong; Tran Dang Khanh; Chung Ill Min

2004-01-01

212

Mixed?weed infestations: Prediction of crop losses for economic weed management in rice  

Microsoft Academic Search

Weed control in Latin America is costly and heavily dependent upon herbicides. Often irrigated rice farmers spray herbicides in late post?emergence at 30–44 days after emergence (d.a.e.). The economic benefits from such late applications are often unclear. Two experimental approaches involving density series of Eclipta alba, Leptochloa filiformis, Eleusine indica a 1:1 mixture of Echinochloa colona and E. crus?galli and

A. J. Fischer; A. Ramirez

1993-01-01

213

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

214

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.

215

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.

216

While soil-applied herbicides can be quite valuable in weed control, misuse can cause crop injury or failure to control weeds. This guide  

E-print Network

While soil-applied herbicides can be quite valuable in weed control, misuse can cause crop injury and persistence of soil-applied herbicides. MT200405 AG issued 5/04 D-4 Getting the Most from Soil-Applied Herbicides by Fabián D. Menalled, Extension Cropland Weeds Specialist, and William E. Dyer, Professor, Weed

Maxwell, Bruce D.

217

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

PubMed Central

Summary Competition between microbial species is a product of, yet can lead to a reduction in, the microbial diversity of specific habitats. Microbial habitats can resemble ecological battlefields where microbial cells struggle to dominate and/or annihilate each other and we explore the hypothesis that (like plant weeds) some microbes are genetically hard-wired to behave in a vigorous and ecologically aggressive manner. These ‘microbial weeds’ are able to dominate the communities that develop in fertile but uncolonized – or at least partially vacant – habitats via traits enabling them to out-grow competitors; robust tolerances to habitat-relevant stress parameters and highly efficient energy-generation systems; avoidance of or resistance to viral infection, predation and grazers; potent antimicrobial systems; and exceptional abilities to sequester and store resources. In addition, those associated with nutritionally complex habitats are extraordinarily versatile in their utilization of diverse substrates. Weed species typically deploy multiple types of antimicrobial including toxins; volatile organic compounds that act as either hydrophobic or highly chaotropic stressors; biosurfactants; organic acids; and moderately chaotropic solutes that are produced in bulk quantities (e.g. acetone, ethanol). Whereas ability to dominate communities is habitat-specific we suggest that some microbial species are archetypal weeds including generalists such as: Pichia anomala, Acinetobacter spp. and Pseudomonas putida; specialists such as Dunaliella salina, Saccharomyces cerevisiae, Lactobacillus spp. and other lactic acid bacteria; freshwater autotrophs Gonyostomum semen and Microcystis aeruginosa; obligate anaerobes such as Clostridium acetobutylicum; facultative pathogens such as Rhodotorula mucilaginosa, Pantoea ananatis and Pseudomonas aeruginosa; and other extremotolerant and extremophilic microbes such as Aspergillus spp., Salinibacter ruber and Haloquadratum walsbyi. Some microbes, such as Escherichia coli, Mycobacterium smegmatis and Pseudoxylaria spp., exhibit characteristics of both weed and non-weed species. We propose that the concept of nonweeds represents a ‘dustbin’ group that includes species such as Synodropsis spp., Polypaecilum pisce, Metschnikowia orientalis, Salmonella spp., and Caulobacter crescentus. We show that microbial weeds are conceptually distinct from plant weeds, microbial copiotrophs, r-strategists, and other ecophysiological groups of microorganism. Microbial weed species are unlikely to emerge from stationary-phase or other types of closed communities; it is open habitats that select for weed phenotypes. Specific characteristics that are common to diverse types of open habitat are identified, and implications of weed biology and open-habitat ecology are discussed in the context of further studies needed in the fields of environmental and applied microbiology. PMID:23336673

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

2013-01-01

218

Weed management in aerobic rice systems under varying establishment methods  

Microsoft Academic Search

Aerobic rice systems, wherein the crop is established via direct-seeding in non-puddled, non-flooded fields, are among the most promising approaches for saving water and labour. However, aerobic systems are subject to much higher weed pressure than conventionally puddled transplanted rice (CPTR). Experiments were conducted for 2 years to develop effective and economical methods for managing weeds in aerobic rice grown

Samar Singh; J. K. Ladha; R. K. Gupta; Lav Bhushan; A. N. Rao

2008-01-01

219

[Pseudomonas syringae - the agent of bacterial diseases of weeds].  

PubMed

The symptoms of bacterial diseases of the associated weeds have been identified and described in the wheat crops grown in different farming systems. On the basis of its morphological, biochemical and serological properties the agent isolated from frost-blite, barnyard grass, wild radish, couch grass, bottle-brush, bindweed and sow thistle has been identified as Pseudomonas syringae. Serological affinity between the weed bacteria and the agent of bacterial diseases of cereals has been established. PMID:24006783

Pasichnik, L A; Savenko, E A; Butsenko, L N; Shcherbina, T N; Patyka, V F

2013-01-01

220

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

221

Herbicide-resistant crops and weed resistance to herbicides.  

PubMed

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

Owen, Micheal D K; Zelaya, Ian A

2005-03-01

222

Weed control in a pigeon pea–wheat cropping system  

Microsoft Academic Search

Pigeon pea (Cajanus cajan (L.) Millsp.) seedlings compete poorly against the rapid growth of warm-season annual weeds. Weed control is required before this heat and drought-tolerant legume can be reliably grown in the U.S. southern Great Plains as a potential source of livestock hay between annual plantings of winter wheat (Triticum aestivum L.). Currently, no herbicides are labeled for use

James E. Bidlack; Andy Middick; Delmar Shantz; Charles T. MacKown; Robert D. Williams; Srinivas C. Rao

2006-01-01

223

United States Department of Agriculture-Agricultural Research Service research on pest biology: weeds.  

PubMed

Over 125 permanent full-time scientists conduct research within the USDA Agricultural Research Service (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 on weed control and integrated crop and soil management. Describing all ARS projects involved with weed biology is impossible, and consequently only research that falls within the following arbitrarily chosen topics is highlighted in this article: dormancy mechanisms; cell division; diversity of rangeland weeds; soil resources and rangeland weeds; poisonous rangeland plants; horticultural weeds; weed traits limiting chemical control; aquatic and semi-aquatic weeds; weed/transgenic wheat hybrids; seedbanks, seedling emergence and seedling populations; and weed seed production. Within these topics, and others not highlighted, the desire of ARS is that good information on weed biology currently translates or eventually will translate into practical advice for those who must manage weeds. PMID:12846326

Forcella, Frank

2003-01-01

224

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

225

Phytotoxicity of sesquiterpene lactone parthenin on aquatic weeds.  

PubMed

The sesquiterpene lactone parthenin, one of the major toxins in an obnoxious weed, parthenium (Parthenium hysterophorus L.), was toxic at 50 ppm to the floating aquatic weeds pistia (Pistia stratiotes L.) and lemna (Lemna pausicostata Hegelm.) and at 100 ppm to water hyacinth (Eichhornia crassipes Mart Solmns.), salvinia (Salvinia molesta Mitchell), azolla (Azolla nilotica Decne.), and spirodella (Spirodella polyrhiza L. Schleid). The lethal dose for the submerged weeds najas (Najas graminea Del.), ceratophyllun (Ceratophyllum demersun L.), and hydrilla (Hydrilla verticillata L. f. Royle) was 25 ppm. The submerged aquatic weeds were more sensitive to parthenin. Water hyacinth was used as a representative for studying the phytotoxicity of parthenin on aquatic weeds. Inhibition of water hyacinth by parthenin was associated with decline in water use, root dysfunction, excessive leakage of solutes from roots indicative of massive damage to cellular membranes, loss of dehydrogenase activity in the roots, and loss of chlorophyll in the leaves. Plant death occurred in a period of one to two weeks. Parthenin phytotoxicity is gradually lost in an aquatic environment as a lethal dose became nonlethal in about 30 days under outdoor conditions. Possible buildup of a toxin concentration may affect population dynamics and a shift in the aquatic weed flora in the immediate area of parthenium stands. Accumulation of the toxin in an aquatic environment, however, at a level sufficient to produce such changes in a natural ecosystem as a consequence of rain washing parthenium plants and leaching of toxin from their residue appears to be unlikely. PMID:24226989

Pandey, D K

1996-01-01

226

Published by: Virginia Cooperative Extension Content Coordinators: E. Scott Hagood, Department of Plant Pathology, Physiology, and Weed Science;  

E-print Network

of Plant Pathology, Physiology, and Weed Science; D. Ames Herbert, Jr., Department of Entomology Produced ............................................................... 2-17 Weeds....................................................................... 2-19 3 Grapes Diseases and Insects in Vineyards............................. 3-1 Weed control in Vineyards

Liskiewicz, Maciej

227

Published by: Virginia Cooperative Extension Content Coordinators: Chuan Hong, Department of Plant Pathology, Physiology and Weed Science  

E-print Network

Pathology, Physiology and Weed Science Peter B. Schultz, Depatment of Entomology Produced by: Communications ................................................................ 2-25 Weeds........................................................................ 2-27 3 Grapes Diseases and Insects in Vineyards .............................. 3-1 Weed control in Vineyards

Liskiewicz, Maciej

228

Published by: Virginia Cooperative Extension Content Coordinators: E. Scott Hagood, Department of Plant Pathology, Physiology, and Weed Science;  

E-print Network

of Plant Pathology, Physiology, and Weed Science; D. Ames Herbert, Jr., Department of Entomology Produced ............................................................... 2-25 Weeds............................................................................. 2-27 Grapes Diseases and Insects in Vineyards............................. 3-1 Weed control in Vineyards

Liskiewicz, Maciej

229

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

E-print Network

Division of Agricultural Sciences and Natural Resources · Oklahoma State University Weed Control.Weedscompeteforwater,nutrients,andlight andextendthetimerequiredtoproduceamarketabletree. Successful weed control helps the grower produce high.Finally, reductionofweedsreducesinterferencewithlaborandequip- mentmovementandimprovestheplantation'sappearance forconsumers. Methods of Weed Control Site

Balasundaram, Balabhaskar "Baski"

230

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

231

Tillage and residue burning affects weed populations and seed banks.  

PubMed

An integrated weed management approach requires alternative management practices to herbicide use such as tillage, crop rotations and cultural controls to reduce soil weed seed banks. The objective of this study was to examine the value of different tillage practices and stubble burning to exhaust the seed bank of common weeds from the northern grain region of Australia. Five tillage and burning treatments were incorporated in a field experiment, at Armidale (30 degrees 30'S, 151 degrees 40'E), New South Wales, Australia in July 2004 in a randomized block design replicated four times. The trial was continued and treatments repeated in July 2005 with all the mature plants from the first year being allowed to shed seed in their respective treatment plots. The treatments were (i) no tillage (NT), (ii) chisel ploughing (CP), (iii) mould board ploughing (MBP), (iv) wheat straw burning with no tillage (SBNT) and (v) wheat straw burning with chisel ploughing (SBC). Soil samples were collected before applying treatments and before the weeds flowered to establish the seed bank status of the various weeds in the soil. Wheat was sown after the tillage treatments. Burning treatments were only initiated in the second year, one month prior to tillage treatments. The major weeds present in the seed bank before initiating the trial were Polygonum aviculare, Sonchus oleraceus and Avena fatua. Tillage promoted the germination of other weeds like Hibiscus trionum, Medicago sativa, Vicia sp. and Phalaris paradoxa later in the season in 2004 and Convolvulus erubescens emerged as a new weed in 2005. The MBP treatment in 2004 reduced the weed biomass to a significantly lower level of 55 g/m2 than the other treatments of CP (118 g/m2) and NT plots (196 g/m2) (P < 0.05). However, in 2005 SBC and MBP treatments were similar in reducing the weed biomass. In 2004, the grain yield trend of wheat was significantly different between CP and NT, and MBP and NT (P < 0.05) with maximum yield of 5898 kg/ha in CP and 5731 kg/ha in MBP. Rainfall before the start of the second trial season promoted the germination of a large numbers of weeds. SBC and MBP treatments reduced the numbers of most of the individual weed species compared with CP, SBNT and NT. SBC was able to destroy a large proportion of seeds most likely through burning and burying some in the soil and was found to be the best treatment in exhausting the seed bank followed closely by MBP which probably buried large number of seeds deep in the soil and promoted others to germinate. CP might have buried some of the seeds in the top 5-10 cm but also promoted parts of the seed bank to germinate. SBNT and NT provided an ideal medium for weeds to germinate and resulted in heavy infestations of weeds. PMID:17390813

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

2006-01-01

232

Microfungal "weeds" in the leafcutter ant symbiosis.  

PubMed

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

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

2008-11-01

233

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

Federal Register 2010, 2011, 2012, 2013

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

2010-05-03

234

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

Code of Federal Regulations, 2013 CFR

...Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE...13) Measures to be employed to prevent danger of noxious weed dissemination; and ...12) Measures to be employed to prevent danger of noxious weed dissemination; and...

2013-01-01

235

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

...Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE...13) Measures to be employed to prevent danger of noxious weed dissemination; and ...12) Measures to be employed to prevent danger of noxious weed dissemination; and...

2014-01-01

236

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....................................................................................................................... 11 TABLE OF TABLES Table 1. Noxious weed management objectives for species targeted in this study

237

Research on crop and weed identification by NIR spectroscopy  

NASA Astrophysics Data System (ADS)

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

Pan, Jiazhi; Tang, Yueming; He, Yong

2007-01-01

238

Engineering hypervirulence in a mycoherbicidal fungus for efficient weed control.  

PubMed

Agents proposed for biocontrol of major weeds in arable row-crop agriculture have not met expectations because an evolutionary balance has developed between microorganism and weed, even when the mycoherbicide is used inundatively at very high levels (>10(4)spores/cm<(2)). Sufficient virulence can be achieved by transferring genes to the microorganism, tipping the evolutionary balance. Virulence was increased ninefold and was more rapidly effected; furthermore, the requirement for a long duration at high humidity was decreased by introducing NEP1 encoding a phytotoxic protein, to an Abutilon theophrasti-specific, weakly mycoherbicidal strain of Colletotrichum coccodes. The parent strain was at best infective on juvenile cotyledons of this intransigent weed. The transgenic strain was lethal through the three-leaf stage, a sufficient time window to control this asynchronously germinating weed. Strategies of coupling virulence genes with fail-safe mechanisms to prevent spread (due to broadened host range) and to mitigate transgene introgression into crop pathogens could be very useful in the biocontrol of major weeds in row crops. PMID:12355116

Amsellem, Ziva; Cohen, Barry A; Gressel, Jonathan

2002-10-01

239

Competition Experiments on Alien Weeds with Crops: Lessons for Measuring Plant Invasion Impact?  

Microsoft Academic Search

Can we quantify the impact of invasive species? Here we use the per-plant competitiveness of alien weeds on crops as a model\\u000a of invasive species impact in general. We reviewed 97 weed–crop competition experiments in 32 papers that included 30 alien\\u000a weed and 14 crop species. The majority (68.92%) were randomised block designs where the alien weed had been either

Montserrat Vilà; Mark Williamson; Mark Lonsdale

2004-01-01

240

Weeding in a Corporate Library as Part of a Collection Maintenance Program  

Microsoft Academic Search

Weeding is an important part of a collection maintenance program. Guidelines are presented for weeding materials in a library which is part of a network of libraries within a company. Factors affecting the weeding of materials such as monographs, serials and internal company reports are explored, along with a discussion concerning some choices available for disposal of these items. This

Richard P. Hulser

1986-01-01

241

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

242

Schnick et al.: Biocontrol of common dandelion 173 Weed Science, 50:173178. 2002  

E-print Network

Schnick et al.: Biocontrol of common dandelion · 173 Weed Science, 50:173­178. 2002 2,4-D@uoguelph.ca Integration of two or more methods in a weed control strategy may produce a positive interaction, possibly decreasing the cost or volume of use of herbicides in tradi- tional weed control strategies

Boland, Greg J.

243

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

E-print Network

South Carolina Pest Management Handbook for Field Crops - 2013 116 GRASS FORAGE WEED CONTROL Mike Marshall, Extension Weed Specialist Newly Sprigged Bermudagrass Herbicide Rate/Acre Broadcast Mode: Apply OUTRIDER at 1.33 oz/A to control johnsongrass, yellow and purple nutsedge, and other weeds

Stuart, Steven J.

244

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 weed control uses crop rotation, early root and stalk destruction, cultivation, and appropriate use) will reduce reliance on tillage and cultivation for early season weed control. Some herbicides may also

Buehrer, R. Michael

245

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, ¾, ½) of herbicides on broadleaf weed control and yield of sugar beet. Phenmedipham + desmedipham + ethofumesate, triflusulfuron, metamitron, chloridazon,

V. Seibutis

246

Quantitative and qualitative evaluation of weed seed bank in organic farming  

Microsoft Academic Search

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

V. Boguzas; A. Marcinkeviciene

2004-01-01

247

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

E-print Network

Evolution of Weediness and Invasiveness: Charting the Course for Weed Genomics C. Neal Stewart, Jr and their evolution remain poorly understood, but genomic approaches offer tremendous promise for elucidating these important features of weed biology. However, the genomic tools and resources available for weed research

Rieseberg, Loren

248

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

Microsoft Academic Search

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

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

2004-01-01

249

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

250

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.

251

Weed Seed Pools Concurrent with Corn and Soybean Harvest in Illinois  

Microsoft Academic Search

A casual glance at most commercially managed corn and soybean fields while traveling at highway speed through central Illinois would suggest that the struggle against weeds is over. Row after row appear to be weed free, and the rare weed escape is confined to a field margin or wet spot. As most farmers will attest, however, the struggle is not

Adam S. Davis

2008-01-01

252

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

253

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

E-print Network

Marshall, Extension Weed Specialist Preplant/Burndown Herbicides for Weed Management in Peanut Herbicide, application rates, adjuvants, and precautions. GLYPHOSATE does not adequately control cutleaf evening primrose Management Handbook for Field Crops - 2014 164 Preplant/Burndown Herbicides for Weed Management in Peanut

Duchowski, Andrew T.

254

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

E-print Network

Marshall, Extension Weed Specialist Preplant Burndown Herbicides for Weed Management in Cotton Herbicide not apply more than 2.0 oz/A for burndown. Add a suitable adjuvant like NIS at 1.0% v/v (1 gal per 100 gal Management Handbook for Field Crops - 2014 71 Preplant Burndown Herbicides for Weed Management in Cotton

Duchowski, Andrew T.

255

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

E-print Network

Marshall, Extension Weed Specialist Preplant Burndown Herbicides for Weed Management in Cotton Herbicide not apply more than 2.0 oz/A for burndown. Add a suitable adjuvant like NIS at 1.0% v/v (1 gal per 100 gal Management Handbook for Field Crops - 2013 64 Preplant Burndown Herbicides for Weed Management in Cotton

Stuart, Steven J.

256

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

E-print Network

Marshall, Extension Weed Specialist Preplant/Burndown Herbicides for Weed Management in Soybean Herbicide a suitable adjuvant like NIS at 1.0% v/v (1 gal per 100 gal of spray solution) to optimize weed control;South Carolina Pest Management Handbook for Field Crops - 2014 216 Preplant/Burndown Herbicides

Duchowski, Andrew T.

257

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

E-print Network

Marshall, Extension Weed Specialist Preplant/Burndown Herbicides for Weed Management in Soybean Herbicide a suitable adjuvant like NIS at 1.0% v/v (1 gal per 100 gal of spray solution) to optimize weed control;South Carolina Pest Management Handbook for Field Crops - 2013 206 Preplant/Burndown Herbicides

Stuart, Steven J.

258

Environmental Research 106 (2008) 203211 Associations between grass and weed pollen and emergency department  

E-print Network

Environmental Research 106 (2008) 203­211 Associations between grass and weed pollen and emergency the short-term effects of exposure to grass and weed pollen on emergency department visits and readmissions were found between weed pollen (including ragweed pollen) and emergency department visits 2 days after

Long, Bernard

259

Email not displaying correctly? View it in your browser. Mobile Weed Manual is Here!  

E-print Network

Email not displaying correctly? View it in your browser. Mobile Weed Manual is Here! The University of Tennessee Turf & Ornamental Weed Science Team has put together a new website and free mobile app called "Mobile Weed Manual," #12;located at www.mobileweedmanual.com. It just went online this week

Tennessee, University of

260

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:30 p.m. Registration 1:30 - 4:30 p.m. Field Crop Weed Control (Russ Hahn) CCA and DEC Credits have been

Keinan, Alon

261

Linkages among agronomic, environmental and weed management characteristics in North American sweet corn  

E-print Network

Linkages among agronomic, environmental and weed management characteristics in North American sweet-Agricultural Research Service, Invasive Weed Management Unit, 1102 S. Goodwin Ave., Urbana, IL 61801, USA b General practices and species interactions (Harper, 1977). In agroecosystems, knowledge of weed community structure

Sims, Gerald K.

262

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.

263

RESEARCH ARTICLE Remarkable changes of weed species in Spanish cereal fields  

E-print Network

RESEARCH ARTICLE Remarkable changes of weed species in Spanish cereal fields from 1976 to 2007 gradients and climatic factors are factors explaining weed species composition and richness in cereal fields from Northern and Central Europe. In the Mediterranean area, the precise factors responsible for weed

Paris-Sud XI, Université de

264

Integration of soil, crop and weed management in low-external-input farming systems  

E-print Network

Integration of soil, crop and weed management in low-external-input farming systems M LIEBMAN diversi®cation are basic components of LEI systems. Weed scientists can improve the use of these practices for weed management by improving knowledge of four relevant ecological mechanisms. First, multispecies crop

Sims, Gerald K.

265

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 control tactics are effective for removing this weed from an onion crop. Both volunteer potato density density on the critical time of weed removal (CTWR) in onion. Yield losses of 2.5, 5.0, and 10% were

Sims, Gerald K.

266

Influence of Planting Date and Weed Interference on Sweet Corn Growth and Development  

E-print Network

Influence of Planting Date and Weed Interference on Sweet Corn Growth and Development Martin M- tween weeds and sweet corn (Zea mays L.); however, little is known about sweet corn growth response to weed interference. Field studies were conducted in 2004 and 2005 near Urbana, IL, to quantify

Sims, Gerald K.

267

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

268

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

269

Data Weeding Techniques Applied to Roget's Thesaurus Uta Priss, L. John Old  

E-print Network

Data Weeding Techniques Applied to Roget's Thesaurus Uta Priss, L. John Old Napier University- riety of "data weeding" techniques that can be applied in order to reduce the size of a concept lattice about which data to select resemble a form of "weeding" in a garden because whether a plant

Old, L. John

270

Managing Weeds in Dry Peas Agronomic and market considerations have sparked an  

E-print Network

Managing Weeds in Dry Peas Agronomic and market considerations have sparked an increased interest in incorporating dry peas into their crop rotation should be aware of the associated weed management challenges to inadequate weed management. For example, a wild oat density of 4 plants/ft2 can lead to a 51 percent loss

Maxwell, Bruce D.

271

Direct and Indirect Impacts of Weed Management Practices on Soil Quality  

E-print Network

275 18 Direct and Indirect Impacts of Weed Management Practices on Soil Quality Richard G. Smith, Matthew R. Ryan, and Fabian D. Menalled Weed management is an ever-present challenge to crop production. Weeds have the poten- tial to usurp resources that would otherwise provide nourishment to growing crops

Maxwell, Bruce D.

272

On the adequacy of GIS-generated weed maps for Precision Farming  

E-print Network

On the adequacy of GIS-generated weed maps for Precision Farming Matthias Backes1 , Lutz Plümer1 1 an increasing importance in modern Precision Farming. For the application of herbicides in a field, maps of weed reason why farmers tend to be hesitant in applying the GIS-generated weed maps. In this paper, the lack

Behnke, Sven

273

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

274

Effects of abiotic factors on species richness and cover in Central European weed communities  

E-print Network

Effects of abiotic factors on species richness and cover in Central European weed communities Petr 2005; accepted 17 February 2005 Abstract Plant species richness and cover of 698 samples of weed flora variables on weed species number and cover, independent of covariance with other variables, were determined

Kratochvíl, Lukas

275

Population-based threshold models describe weed germination and emergence patterns across varying  

E-print Network

Population-based threshold models describe weed germination and emergence patterns across varying and success of control measures often hinges on the timing of weed emergence. We used population of herbicide-resistant and -susceptible Echinochloa phyllopogon, a weed of temperate paddy rice, and applied

Bradford, Kent

276

Weed Seed Survival in Livestock Systems Jeanie Katovich and Roger Becker  

E-print Network

Weed Seed Survival in Livestock Systems Jeanie Katovich and Roger Becker Department of Agronomy to the soil. However, many assume manure is always rich in weed seeds. The opposite is probably the case as most of our harvested forage is relatively free of weed seeds. Exceptions obviously exist

Minnesota, University of

277

Metolachlor, S-metolachlor and their role within sustainable weed-management  

Microsoft Academic Search

The herbicide metolachlor has been widely used for over 20 years for selective weed control in more than 70 crops worldwide. Its favourable soil behaviour and low risk for developing weed resistance means that metolachlor integrates well into sustainable weed-management practices, such as conservation tillage. Metolachlor consists of four stereoisomers, with herbicidal activity coming mainly from the S-isomer pair. A

Peter J. O'Connell; Christian T. Harms; James R. F. Allen

1998-01-01

278

Screening Green Manure Cover Crops for their Allelopathic Effects on Some Important Weeds Found in Zimbabwe  

Microsoft Academic Search

Weed control is a serious problem in smallholder conservation agriculture farming areas in Zimbabwe. Green Manure Cover Crops (GMCCs), which improve soil fertility and reduce weeds through allelopathy, are likely to reduce the cost of weed control in these areas. A laboratory study was conducted at the University of Zimbabwe to investigate the effect of extracts of eleven GMCCs on

Mt Pleasant

2013-01-01

279

The Potential of Allelopathy as a Tool for Weed Management in Crop Fields  

Microsoft Academic Search

The increasing emphasis now placed on weed management as opposed to weed control raises the question of the role of allelopathy in agricultural systems. Evidence of allelopathic interactions between crops and weeds is briefly reviewed and two experiments designed to demonstrate the allelopathic effects of plant residues on seed germination are described. From these experiments it can be seen that

M. A. Altieri; J. D. Doll

1978-01-01

280

Poisonous weed species and their significance for cattle production in Serbia region  

Microsoft Academic Search

Weed species that grow on agricultural land together with crop plants cause crop yield reduction and increased costs of agricultural production due to the cost of their control. Beside these direct damages, some weed species cause indirect damages by their adverse effects to human and domestic animals health. In our agroecological conditions the most problematic poisonous weed species are: Solanum

Konstantinovic Branko; Meseldzija Maja

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

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

283

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

284

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

285

Protecting the Environment Using Integrated Weed Management in Lawns  

E-print Network

T here are more than 2 million acres of lawns in Texas and nearly 1.9 million acres of maintained turf in parks, golf courses and other public places. To control weeds in lawns, approximately 50 per- cent of homeowners use herbicides. The use... of herbicides increases as the public use of an area increases. An average of 59 percent of all turf areas are treated with some amount of weed control chemical. As much as 87 per- cent of school yard and turf areas and 97 percent of golf courses...

Ketchersid, Mary; Baumann, Paul A.

2008-03-27

286

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

287

Suitability of arable weeds as indicator organisms to evaluate species conservation effects of management in agricultural ecosystems  

Microsoft Academic Search

The overall objective of this study is to examine the application of arable weeds as indicator organisms of biodiversity in agro-ecosystems to evaluate species conservation effects of management practices.Both investigations of interactions between weeds with heterotrophic consumers and strong overall correlations between the number of weed species and the total species diversity indicate that arable weeds are “key species”, the

Harald Albrecht

2003-01-01

288

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

289

Competitive effects of introduced annual weeds on some native and reclamation species in the Powder River Basin, Wyoming  

Microsoft Academic Search

Four experiments were conducted to examine the competitive effects of introduced annual weeds on certain native and reclamation species. The first experiment was initiated by discing three sites in the Powder River Basin, Wyoming, at three distances from introduced weed seed sources. Introduced weed colonization was greatest when a seed source was located nearby. Higher weed cover resulted in reductions

E. B. Allen; D. H. Knight

1980-01-01

290

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

291

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

PubMed Central

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

2010-01-01

292

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

PubMed

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

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

1990-07-01

293

Laser-induced fluorescence for discrimination of crops and weeds  

NASA Astrophysics Data System (ADS)

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

Hilton, Peter J.

2000-11-01

294

Chemical Weed and Brush Control: Suggestions for Rangeland  

E-print Network

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 ragweed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 rayless goldenrod . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 rosin weed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8... Remarks Broadcast rate per acre Individual plant/spot treatment* surmount Vh** 1 .5 to 2 pt . (0 .25 to 0 .33 lb .) Vh 1% Pasturegard Vh 1 .5 to 2 pt . (0 .38 t 0 .5 lb .) Vh 0 .75% Rayless goldenrod (jimmyweed) escort or cimarron Vh 3 ?4 oz . (0 .45 oz...

McGinty, Allan; Ansley, Jim; Cadenhead, J. F.; Hamilton, Wayne T.; Hanselka, C. Wayne; Hart, Charles R.; Ueckert, Darrell

2005-04-25

295

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...

296

Herbicide Leaching Column for a Weed Science Teaching Laboratory.  

ERIC Educational Resources Information Center

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

Ahrens, W. H.

1986-01-01

297

Weed Management in No-Till Zucchini Squash  

Microsoft Academic Search

Weed control in no-tillage (NT) zucchini squash (Cucurbita pepo L.) was determined for various preemergence (PRE) herbicide combinations in herbicide-killed ‘Wheeler’ winter rye (Secale cereale L.) or bare soil. Winter rye provided 65% and 75% control of redroot pigweed (Amaranthus retroflexus L.) and smooth crabgrass [Digitaria ischaemum (Schreb.) Schreb. ex Muhl.], respectively, in the absence of herbicides compared with no

S. Alan Walters; Bryan G. Young

2011-01-01

298

From Conventional to Organic: Weed Management Principles for the  

E-print Network

Organic No-till Organic & No-till Rotations After 4 yr, Bozeman (Counted prior to spraying No-till) P Thistle www.btny.purdue.edu/Extension/Weeds/NoTillID/ #12;#12;A healthy alfalfa stand can help you

Maxwell, Bruce D.

299

Weed control and desiccation strategies in chickpea Executive Summary  

E-print Network

to soil-applied herbicides only. Most chickpea acres are grown under no-till conditions, which make weed with several labeled and experimental herbicides in conventional and no-till systems, 2) determine chickpea in the no- till system from soil-applied metribuzin at 0.25-0.33 lb/A. Postemergence metribuzin in the no-till

Lawrence, Rick L.

300

Weed Management in Alfalfa Stands Dr. Case R. Medlin  

E-print Network

be applied to actively growing alfalfa for control of emerged weeds. Roundup Ultra® must be applied, translocated herbicides, such as Roundup Ultra® or Touchdown® , will effectively control the root systems: Roundup Ready® soybeans with multiple POST applications of Roundup Ultra® or #12;Touchdown® , followed

301

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

302

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

303

Introduced weeds pollinated by introduced bees: Cause or effect?  

Microsoft Academic Search

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

M. E. HANLEY; D. GOULSON

2003-01-01

304

[Research on distinguishing weed from crop using spectrum analysis technology].  

PubMed

Automatic detection of weeds is necessary for site--specific application of herbicides or precise physical weed control. Leaf reflectance is mainly determined by photosynthetic pigments, leaf structural properties and water content, so spectral reflectance characteristics can be used for weed discrimination. The spectral reflectance of cotton, rice and weeds was determined in the range from 350 to 2 500 nm using the Analytical Spectral Device Full Range FieldSpec Pro (ASD) in laboratory. The discrimination analysis was done using the statistical software package SAS. The characteristic wavelengths were selected by using STEPDISC procedure. With the selected characteristic wavelengths, discriminant models were developed using the DISCRIM procedure in SAS. For distinguishing spine-greens from cotton, three characteristic wavelengths, 385, 415, and 435 nm, were selected, and good classification performance (100% accuracy) was achieved. The combination of characteristic wavelengths 415 and 435 nm has the biggest contribution to discrimination model. For distinguishing barnyard-grass from rice, five characteristic wavelengths, 375, 465, 585, 705, and 1 035 nm, were selected, and also good classification performance (100% accuracy) was obtained. The transition point from yellow to orange wavelength (585 nm) and the wavelength 705 nm in the red edge contributed more to discrimination model. PMID:19445228

Chen, Shu-Ren; Li, Yi-Xin; Mao, Han-Ping; Shen, Bao-Guo; Zhang, Yu-Zhu; Chen, Bin

2009-02-01

305

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

306

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

307

Are we making significant progress in mechanical weed control research?  

Microsoft Academic Search

This study investigates whether researchers' perceptions of good research are in agreement with current research practice as reflected in Weed Research. A high degree of agreement is assumed to indicate progress. The instrument used to survey researchers perceptions was a questionnaire consisting of 28 items related to (1) research methodologies, (2) research priorities, (3) quality of publications, (4) future developments

J. Rasmussen

308

RESEARCH ARTICLE Biodegradable mulch instead of polyethylene for weed  

E-print Network

processing tomato production (Lycopersicon escu- lentum P. Mill.) due to competition with water, nutrients P. Mill.) in Spain achieving a generally high weed control but caus- ing a serious waste problem and light (Weaver and Tan 1983; Patrap et al. 1997). Most damaging species are Solanum nigrum

Paris-Sud XI, Université de

309

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

PubMed

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

310

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

311

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

312

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

313

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

314

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

315

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

...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

316

A Hybrid Differential Invasive Weed Algorithm for Congestion Management  

NASA Astrophysics Data System (ADS)

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

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

317

Deciphering the evolution of herbicide resistance in weeds.  

PubMed

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

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

2013-11-01

318

Biological Weed Control in Plantains (Musa AAB) with Egusi Melon (Colocynthis citrullus L.)  

Microsoft Academic Search

The experiment investigated the effect of intercropping plantains with 2,500, 5,000 and 10,000 melons\\/ha on delayed weeding for 3, 5 and 7 months respectively after planting. The yield of melons decreased with increased population. Intercropping plantains with 5,000 melons\\/ha suppressed weed growth for 7 months and significantly enhanced plantain establishment growth and yield. At 2,500 melons\\/ha, weeding could be delayed

J. C. Obiefuna

1989-01-01

319

Nematode, fungi, and weed control using Telone C35 and colored plastic mulches  

Microsoft Academic Search

Methyl bromide controls three major problems in crop production: weeds, nematodes and phytopathogenic fungi. An alternative system was investigated that used various colored plastic mulches with Telone C35 (63.4% 1,3-dichlropropene, 34.7% chloropicrin, 1.9% inert ingredients). This alternative to methyl bromide was to investigate: 1) control weeds through wavelength selective plastic mulches, 2) control fungi by chloropicrin, and 3) control weeds

J. E. Thomas; L.-T. Ou; L. H. Allen Jr.; J. C. Vu; D. W. Dickson

2009-01-01

320

A vision-based method for weeds identification through the Bayesian decision theory  

Microsoft Academic Search

One of the objectives of precision agriculture is to minimize the volume of herbicides that are applied to the fields through the use of site-specific weed management systems. This paper outlines an automatic computer vision-based approach for the detection and differential spraying of weeds in corn crops. The method is designed for post-emergence herbicide applications where weeds and corn plants

Alberto Tellaeche; Xavier P. Burgos-artizzu; Gonzalo Pajares; Angela Ribeiro

2008-01-01

321

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

322

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

323

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

324

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

325

The weeds from the thatch roofs of medieval cottages from the south of England  

Microsoft Academic Search

Late medieval soot-coated thatch includes a number of very well preserved weeds as well as cereals or reeds. This paper investigates\\u000a the weeds from the thatch roofs of 13 cottages from the south of England. It describes the exceptional preservation of the\\u000a weeds which include plant parts rarely recorded in archaeological contexts and the information they can give about late

Dominique de Moulins

2007-01-01

326

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

327

Remarkable changes of weed species in Spanish cereal fields from 1976 to 2007  

Microsoft Academic Search

Management practices, geographical gradients and climatic factors are factors explaining weed species composition and richness\\u000a in cereal fields from Northern and Central Europe. In the Mediterranean area, the precise factors responsible for weed distribution\\u000a are less known due to the lack of data and surveys. The existence of weed survey data of year 1976 in the Zaragoza province\\u000a of the

Alicia Cirujeda; Joaquín Aibar; Carlos Zaragoza

328

Weed seedbank response to planted fallow and tillage in southwest Nigeria  

Microsoft Academic Search

Planted fallows are an alternative to the unsustainable bush fallow for improved soil and weed management in the tropics.\\u000a However, the interactive effects of planted fallows and tillage on the weed seedbank are not well documented in the tropical\\u000a environment. The effect of fallow type and tillage on the weed seedbank in the soil was assessed in 1995 and 1996

F. Ekeleme; D. Chikoye; I. O. Akobundu

2005-01-01

329

Improving weed management and crop productivity in maize systems in Zimbabwe  

Microsoft Academic Search

Keywords: Intercropping, narrow planting, precise fertilizer placement, radiation interception, leaf stripping, detasselling, Land Equivalent Ratio, maize, pumpkin, dry beans, reduced herbicide dosages<\\/o:p><\\/span>In the tropics, weeds cause more crop losses and farmers spend more of their time weeding crops than in any other part of the world. Weeds form a major factor which contributes to the miserable quality of

A. B. Mashingaidze

2004-01-01

330

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

331

Critical period of weed interference in cocoyam\\/maize\\/sweet potato intercrop  

Microsoft Academic Search

An experiment was conducted at Umudike in 1981 and 1982 on a sandy loam soil in the rain forest zone of Nigeria, to determine the critical weed?free requirement and the critical duration of weed interference in cocoyam\\/sweet potato\\/maize intercrop combination. The major weeds present in the weedy control crop mixture during the 2 years included grasses, broad?leaves and sedges. The

R. P. A. Unamma; T. Enyinnia; J. F. Emezie

1985-01-01

332

Water Hyacinths and Alligator Weeds for Final Filtration of Sewage  

NASA Technical Reports Server (NTRS)

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

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

1976-01-01

333

Weed Busters: How to Get Drummond's and Common Goldenweed  

E-print Network

label directions. ? The cost of treatment escalates rapidly as number of plants per acre increases. ? Do not spray when the plants are wet. ?Avoid contacting desirable plants and shrubs with spray. ? Controlling Drummond?s and common goldenrod is not a... livestock or deer, and few cases of poisoning are document- ed. A close relative, rayless goldenrod, causes signif- icant livestock losses annually in West Texas. (See Extension publication L-5464, Weed Busters: How to Repel Rayless Goldenrod.) In recent...

2005-03-07

334

Integrated weed management (IWM): will it reduce herbicide use?  

PubMed

The Sustainable Use of Pesticides Directive (2009/128/EC), part of the EU Thematic Strategy for Pesticides, requires Integrated Pest Management (IPM) to be actively promoted. A key objective is to give greater priority to non-chemical methods of plant protection to reduce the impact of pesticides on human health and the environment. Integrated Weed Management (IWM) can be considered part of IPM, and many non-chemical methods are available. For example, a recent review of methods for control of Alopecurus myosuroides (black-grass) in winter wheat found the following mean annual levels of control: ploughing 67%; delayed drilling 37%; fallowing 70%; higher seed rates 30%; competitive cultivars 27%. In comparison with herbicides these efficacy levels are mediocre, and A. myosuroides would be classified as resistant (R) or moderately resistant (MR) to all these methods if the criteria used by the Chemicals Regulation Directorate in the UK for assigning ratings to herbicide efficacy were used. It is, therefore, not surprising that farmers are reluctant to embrace IWM and continue to place greater.reliance on herbicides as a more reliable and cost effective method of weed control. While non-chemical methods will not replace herbicides on most farms, reduced reliance on herbicides will be necessary both for practical (increasing resistance, lack of new herbicides) and political reasons (complying with EU legislation). Farmers will use nonchemical control methods when they have a major weed problem, and have no alternative, but they must be encouraged to adopt IWM at an earlier stage. Research into IWM must be relevant and practical, and not simply conducted as some sort of 'academic' exercise. More effective knowledge transfer is vital, and this is a challenge due to the decline in independent, state funded, advisory services in many European countries. The question arises; is it possible to achieve reductions in pesticide use by simply promoting non-chemical methods of weed control, or will statutory limits on pesticides be needed to achieve this goal? PMID:21542466

Moss, S R

2010-01-01

335

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

336

Are some weeds sleeping? Some concepts and reasons  

Microsoft Academic Search

Summary  Sleeper weeds, a relatively new concept, are defined as a sub-group of invasive plant species for which their population sizes\\u000a are known to have increased significantly more than 50 years after they became naturalized. The invasions of the European\\u000a herb Hieracium pilosella into New Zealand, the northeast Asian Fallopia japonica and the Sicilian Senecio squalidus into Britain are presented as

R. H. Groves

2006-01-01

337

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.

338

Stratification requirements for seed dormancy alleviation in a wetland weed.  

PubMed

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

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

2013-01-01

339

Impact of adjuvants on bentazon efficacy on selected broadleaf weeds  

Microsoft Academic Search

Tank-mix adjuvants can increase the efficacy of herbicides. Therefore, the effects of different rates of bentazon alone or tank-mixed with ammonium sulfate, non-ionic (0.25% Induce) or organosilicone (0.1% Kinetic) adjuvants were investigated on cocklebur (Xanthium strumarium), black nightshade (Solanium nigrum), velvetleaf (Abutilon theophrasti), and stranglervine (Morrenia odorata) under greenhouse condition. There were variations in susceptibility of the four weed species

Hussein Fawzy H. Abouziena; Shiv D. Sharma; Megh Singh

2009-01-01

340

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

341

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

342

Data Weeding Techniques Applied to Roget’s Thesaurus  

Microsoft Academic Search

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

Uta Priss; L. John Old

343

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

PubMed

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

Campbell, Lesley G; Snow, Allison A

2009-02-01

344

Herbicide-resistant weeds in Europe: the wider implications.  

PubMed

Herbicide-resistance occurs in 55 weed species in 21 European countries. 91% of cases are associated with just four herbicide mode of action groups: ACCase and ALS inhibitors, and triazine and urea/amide photosynthetic inhibitors. There are also a few cases of resistance to bypiridiliums, dinitroanilnes and synthetic auxins. Resistance to ALS inhibitors tends to be less prevalent in Europe than elsewhere, but is likely to increase. A small scale survey showed that Alopecurus myosuroides is considered to be the most important herbicide-resistant weed in Europe at present. Lolium spp., and to a lesser extent Papaver rhoeas and Avena spp., were also highlighted as being of major importance in many countries. One consequence of the ongoing EC review of pesticides may be a reduction in the range of modes of action available to European farmers. This may reduce the opportunities for rotating different modes of action as a method of reducing resistance risk. Greater dependence on high resistance risk herbicides, such as ACCase and ALS inhibitors, because of lack of alternative modes of action, is likely to increase the incidence of resistance in grass-weeds. PMID:15759389

Moss, S R

2004-01-01

345

Integration of agronomic practices with herbicides for sustainable weed management in aerobic rice.  

PubMed

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

346

Katovich et al.: Purple loosestrife survival 565 Weed Science, 51:565568. 2003  

E-print Network

of late emerging purple loosestrife (Lythrum salicaria) seedlings Elizabeth J. Stamm Katovich. Nomenclature: Purple loosestrife, Lythrum salicaria L. LYTSA. Key words: Crown survival, weed biology, wetlands

Gray, Matthew

347

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

348

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

... (a) Noxious-weed seeds in the District of Columbia are: Quackgrass (Elytrigia repens ), Canada thistle (Cirsium arvense ), field bindweed (Convolvulus arvensis ), bermudagrass (Cynodon dactylon ), giant bermudagrass...

2014-01-01

349

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

Code of Federal Regulations, 2013 CFR

... (a) Noxious-weed seeds in the District of Columbia are: Quackgrass (Elytrigia repens ), Canada thistle (Cirsium arvense ), field bindweed (Convolvulus arvensis ), bermudagrass (Cynodon dactylon ), giant bermudagrass...

2013-01-01

350

Weed Science Society of America Biocontrol of Common St. Johnswort (Hypericum perforatum) with Chrysolina hyperici and  

E-print Network

Weed Science Society of America Biocontrol of Common St. Johnswort (Hypericum perforatum,herbivory,integrated control,Aphis chloris. Abbreviations: C.g.-hypericum,Colletotrichumgloeosporioides f. sp. hypericum

Reekie, Ed

351

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

352

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

353

Host status of six major weeds to Meloidogyne chitwoodi and Pratylenchus penetrans, including a preliminary field survey concerning other weeds  

Microsoft Academic Search

A glasshouse experiment was carried out to investigate the host status of six important weeds in intensive agricultural cropping systems to Meloidogyne chitwoodi and Pratylenchus penetrans. Senecio vulgaris L., Capsella bursa-pastoris (L.) Medic. and Solanum nigrum L. were hosts of M. chitwoodi with reproduction factors of 2.5, 2.6 and 7.8, respectively. Echinochloa crusgalli (L.) Beauv. and Stellaria media (L.) Vill.

Vhukile Kutywayo; Thomas H. Been

2006-01-01

354

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

355

Phytotoxicity of the volatile monoterpene citronellal against some weeds.  

PubMed

A study was undertaken to assess the phytotoxicity of citronellal, an oxygenated monoterpenoid with an aldehyde group, towards some weedy species [Ageratum conyzoides L., Chenopodium album L., Parthenium hysterophorus L., Malvastrum coromandelianum (L.), Garcke, Cassia occidentalis L. and Phalaris minor Retz.]. A significant effect on weed emergence and early seedling growth was observed in a dose-response based laboratory bioassay in a sand culture. Emergence of all test weeds was completely inhibited at 100 micro/g sand content of citronellal. Seeds of A. conyzoides and P. hysterophorus failed to emerge even at 50 microg/g content. Root length was inhibited more compared to shoot length. The failure of root growth was attributed to the effect of citronellal on the mitotic activity of growing root tips cells as ascertained by the onion root tip bioassay. At 2.5 mM treatment of citronellal, mitosis was completely suppressed and at higher concentrations cells showed various degrees of distortion and were even enucleated. The post-emergent application of citronellal also caused visible injury in the form of chlorosis and necrosis, leading to wilting and even death of test weeds. Among the test weeds, the effect was severe on C. album and P. hysterophorus. There was loss of chlorophyll pigment and reduction in cellular respiration upon citronellal treatment indicating the impairment of photosynthetic and respiratory metabolism. Scanning electron microscopic studies in C. occidentalis leaves upon treatment of citronellal revealed disruption of cuticular wax, clogging of stomata and shrinkage of epidermal cells at many places. There was a rapid electrolyte leakage in the leaf tissue upon exposure to citronellal during the initial few hours. In P. minor electrolyte leakage in response to 2 mM citronellal was closer to the maximum leakage that was obtained upon boiling the tissue. The rapid ion leakage is indicative of the severe effect of citronellal on the membrane structure and loss of membrane integrity. In all, the study concludes that citronellal causes a severe phytotoxicity on the weeds. PMID:16869489

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

2006-01-01

356

Clover as a cover crop for weed suppression in an intercropping design  

Microsoft Academic Search

Weeds often form a major problem in weakly competitive vegetable crops, particularly in low input systems. Undersown cover crops can be used to suppress weeds, but often put too high a competitive pressure on the main crop. Cover crop selection is one of the potential means that can be used to design or optimize these intercropping systems. The objective of

N. G. den Hollander; L. Bastiaans; M. J. Kropff

2007-01-01

357

Corn and weed residue decomposition in northeast Ohio organic and conventional dairy farms  

Microsoft Academic Search

Increasingly, farmers claim that management practices can significantly influence soil quality. For instance, it is common practice for dairy farms in their rotation cycle to harvest grain and then leave stubble and weeds over winter on the soil surface before ploughing in spring ahead of planting crops. Corn stubble and weeds protect soil in winter, decompose through the seasons, and

R. I Vazquez; B. R Stinner; D. A McCartney

2003-01-01

358

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

359

Uncropped edges of arable fields managed for biodiversity do not increase weed occurrence in adjacent crops  

Microsoft Academic Search

Ten experimental management regimes, designed to quantify benefits to weed control and wildlife conservation on uncropped field edges of expanded width, were examined for effects on the weed flora within adjacent arable crops. The treatments involved cutting, sowing and herbicide regimes, with differing effects on plant and invertebrate populations. The relative abundance of all plant species within the adjacent crop

H. Smith; L. G. Firbank; D. W. Macdonald

1999-01-01

360

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

361

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

362

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

363

Response of Rice Genotypes to Weed Competition in Dry Direct-Seeded Rice in India  

PubMed Central

The differential weed-competitive abilities of eight rice genotypes and the traits that may confer such attributes were investigated under partial weedy and weed-free conditions in naturally occurring weed flora in dry direct-seeded rice during the rainy seasons of 2011 and 2012 at Ludhiana, Punjab, India. The results showed genotypic differences in competitiveness against weeds. In weed-free plots, grain yield varied from 6.6 to 8.9?t?ha?1 across different genotypes; it was lowest for PR-115 and highest for the hybrid H-97158. In partial weedy plots, grain yield and weed biomass at flowering varied from 3.6 to 6.7?t?ha?1 and from 174 to 419?g?m?2, respectively. In partial weedy plots, grain yield was lowest for PR-115 and highest for PR-120. Average yield loss due to weed competition ranged from 21 to 46% in different rice genotypes. The study showed that early canopy closure, high leaf area index at early stage, and high root biomass and volume correlated positively with competitiveness. This study suggests that some traits (root biomass, leaf area index, and shoot biomass at the early stage) could play an important role in conferring weed competitiveness and these traits can be explored for dry-seeded rice. PMID:25093205

Mahajan, Gulshan; Ramesha, Mugalodi S.; Chauhan, Bhagirath S.

2014-01-01

364

Effects of alternative management systems on weed populations in hazelnut ( Corylus avellana L.)  

Microsoft Academic Search

Weed management in hazelnut is a major production challenge, with glyphosate being the main herbicide used. Field trials were conducted from 2003 to 2005 to evaluate effects of cover crops on weed populations, and assess efficacy of mechanical control methods used alone or in combination with herbicide applications. The cover crop treatments consisted of ryegrass (Lolium multiflorum Lam.), hairy vetch

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

2006-01-01

365

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

366

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

Code of Federal Regulations, 2013 CFR

...noxious-weed seeds shall be recognized and shall be applied to the number of noxious-weed seeds found by analysis in the quantity of seed specified...corresponding numbers in Column Y are found by analysis in the administration of the Act....

2013-01-01

367

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

...noxious-weed seeds shall be recognized and shall be applied to the number of noxious-weed seeds found by analysis in the quantity of seed specified...corresponding numbers in Column Y are found by analysis in the administration of the Act....

2014-01-01

368

INVESTIGATIONS OF WEEDS AS RESERVOIRS OF PLANT-PARASITIC NEMATODES IN AGRICULTURAL SYSTEMS IN NORTHERN FLORIDA  

Microsoft Academic Search

In addition to their direct effects on crop production through competition and allelopathy, weeds can serve as reservoirs of other pests including plant-parasitic nematodes, resulting indirectly in yield loss. Weeds enable plant-parasitic nematodes to survive in the absence or even presence of the crop, thus providing a source of nematode infection for the following season. The purpose of this study

Lisa Myers; Koon-Hui Wang; Robert McSorley; Carlene Chase

369

Evaluation of different herbicides for protection of gladiolus ( Gladiolus spp.) crop from weeds  

Microsoft Academic Search

A field experiment to study the effects of various pre- and post-emergence herbicides on weed infestation and on corm and cormel production in three gladiolus (Gladiolus spp.) cultivars was carried out during 1997–2000 at IHBT, Palampur. The main weeds infesting the experimental farm were Ageratum conyzoides, Gnaphalium peregrinum, Plantago lanceolata, Cynodon dactylon, Amaranthus viridis, Paspalum dilatatum, Portulaca oleracea, Euphorbia hirta,

S. Manuja; Raja Ram; R. D. Singh; D. Mukherjee

2005-01-01

370

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

Microsoft Academic Search

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

H. L. HINZ

371

Weed control and sensitivity of oats ( Avena sativa) with various doses of saflufenacil  

Microsoft Academic Search

Saflufenacil is a new herbicide being developed by BASF for broadleaved weed control in maize, soybean and other crops prior to crop emergence. Six field studies were conducted in Ontario, Canada over a three year period (2008–2010) to evaluate the potential of saflufenacil applied pre-emergence (PRE) at various doses for broadleaved weed control in oats. Saflufenacil applied PRE caused minimal

Nader Soltani; Christy Shropshire; Peter H. Sikkema

372

The efficacy of pre-emergence herbicides on problem weeds in woodland regeneration  

Microsoft Academic Search

Weeds germinating from seed are serious competitors for resources with young trees and can delay or prevent woodland establishment and regeneration. However, there is only limited information available on which pre-emergence herbicides are effective on problem weeds that commonly occur in these situations, in particular for perennial species germinating on fertile ex agricultural sites. Following previously reported glasshouse screening experiments

F. L. Dixon; D. V. Clay; I. Willoughby

2006-01-01

373

Dalmatian Toadflax, an Invasive Exotic Noxious Weed, Threatens Flagstaff Pennyroyal Community Following Prescribed Fire  

Microsoft Academic Search

Many noxious weed infestations are initiated or increased by soil disturbance. With the recent emphasis on reintroduction of fire into natural ecosystems there has been increased interest in the effects of noxious weeds following fires. This paper discusses the effects of fire on Flagstaff pennyroyal, a Forest Service Region 3 sensitive plant, and the subsequent infesta- tion of the project

BARBARA GOODRICH PHILLIPS; DEBRA CRISP

374

Sustainable Agricultural Practices for Weed Management: Implications to Agricultural Extension Education  

Microsoft Academic Search

The paper examines the scope of issues related to sustainable agricultural practices associated with weed control in Iowa. The results of the survey indicated that a majority of respondents use sustainable agricultural practices associated with weed control, and continued to show interest in learning about those practices they consider sustainable. Respondents are likely to get interested in learning about the

Dido G. Kotile; Robert A. Martin

2000-01-01

375

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 landscapes and the management options. Urban landscape is broadly defined as the area of greenery integrated

Chen, Kuang-Yu

376

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

E-print Network

Effects of Weed Resistance Concerns and Resistance Management Practices on the Value of Roundup Resistance Concerns and Resistance Management Practices on the Value of Roundup Ready® Crops T.M. Hurley Tucson, AZ Abstract This study estimates grower benefits of Roundup-Ready® (RR) weed management programs

Mitchell, Paul D.

377

Factors affecting field weed and field margin flora on a farm in Essex, UK  

Microsoft Academic Search

Field margins, particularly hedgerows, are important refuges for many species in intensively managed arable landscapes. Their management is influenced by the perception that weed species colonise adjacent crops. Mobile species, such as beetles, are able to use field margins as corridors to recolonise suitable habitat. This study examines whether field margins influence adjacent weed flora, and if there is evidence

E. J. P. Marshall; G. M. Arnold

1995-01-01

378

Analysis of weed dispersal to predict chances of re-colonisation  

Microsoft Academic Search

The protection of rare arable weeds and the restoration of biodiversity in agroecosystems have become an important issue in most European countries. Traditional analyses of weed dispersal focussing on the prediction and control of infestations have to be adapted to the new aim of restoration ecology by quantifying chances of re-colonisation within fields and across field borders. This study analyses

A. Bischoff

2005-01-01

379

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

380

Mixed cropping systems for biological control of weeds and pests in organic oilseed crops  

Microsoft Academic Search

Summary Agricultural advantages of mixed cropping are gained from biological effects like light competition offering weed-suppressing capacities, or by diversifi cation of plant covers to break development cycles of pests. These effects were measured in a two-year project on mixed cropping with organic oilseed crops. It was found that weeds can be effi ciently suppressed in organic linseed (Linum usitatissivum)

H M PAULSEN; M SCHOCHOW; B ULBER; S KÜHNE; G RAHMANN

2006-01-01

381

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

382

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

383

When divergent life histories hybridize: insights into adaptive life-history traits in an annual weed  

E-print Network

weed Lesley G. Campbell1,2 , Allison A. Snow1 and Patricia M. Sweeney1 1 Department of Evolution: contemporary evolution, crop­wild hybridization, life history, natural selection, Raphanus, rapid evolution. · We created F1 hybrids of wild radish, an early flowering, small-stemmed weed, and its late

Snow, Allison A.

384

When divergent life histories hybridize: insights into adaptive life-history traits in an annual weed  

E-print Network

weed Lesley G. Campbell1,2 , Allison A. Snow1 and Patricia M. Sweeney1 1 Department of Evolution Key words: contemporary evolution, crop­wild hybridization, life history, natural selection, Raphanus of hybrid and nonhybrid weeds. · We created F1 hybrids of wild radish, an early flowering, small

Snow, Allison A.

385

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 Tucson, AZ Abstract The introduction and rapid adoption of herbicide tolerant crops has renewed interest

Mitchell, Paul D.

386

Discrete invasive weed optimization algorithm: application to cooperative multiple task assignment of UAVs  

Microsoft Academic Search

This paper presents a novel discrete population based stochastic optimization algorithm inspired from weed colonization. Its performance in a discrete benchmark, time-cost trade-off (TCT) problem, is evaluated and compared with five other evolutionary algorithms. Also we use our proposed discrete invasive weed optimization (DIWO) algorithm for cooperative multiple task assignment of unmanned aerial vehicles (UAVs) and compare the solutions with

Mohsen Ramezani Ghalenoei; Hossein Hajimirsadeghi; Caro Lucas

2009-01-01

387

Managing the delay of evolution of herbicide resistance in parasitic weeds  

Microsoft Academic Search

Acetolactate synthase (ALS)?inhibiting imidazolinone and sulphonylurea herbicides have been found to be effective in selectively controlling the pernicious parasitic weeds Orobanche, Striga and Alectra spp. in some crops. This control could be effected both as whole field applications and as seed dressings. Weeds rapidly evolve resistance to this single?target, high mutation frequency group of herbicides, which usually exert heavy selection

J. Gressel; L. Segel; J. K. Ransom

1996-01-01

388

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

E-print Network

Mike Marshall, Extension Weed Specialist Preplant/Burndown Herbicides for Weed Management in Small Grains Herbicide Rate/Acre Broadcast Mode of Action Preharvest Interval Restricted Entry Interval before crop emergence). Consult glyphosate product to determine if an adjuvant is needed. If an adjuvant

Duchowski, Andrew T.

389

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

E-print Network

Mike Marshall, Extension Weed Specialist Preplant/Burndown Herbicides for Weed Management in Small Grains Herbicide Rate/Acre Broadcast Mode of Action Preharvest Interval Restricted Entry Interval before crop emergence). Consult glyphosate product to determine if an adjuvant is needed. If an adjuvant

Duchowski, Andrew T.

390

Suitability of graminaceous weed species as host plants for rice leaffolders, Cnaphalocrocis medinalis and Marasmia patnalis  

Microsoft Academic Search

The suitability of 12 graminaceous weeds of ricefields as host plants for two rice leaffolders, Cnaphalocrocis medinalis (Guenée) and Marasmia patnalis Bradley (Lepidoptera: Pyralidae) was compared to a susceptible (IR36) and a moderately resistant (TKM6) rice variety in laboratory and greenhouse tests. Although rice was the most preferred host of the two leaffolder species, their responses to the test weeds

Z. R. Khan; M. L. P. Abenes; N. J. Fernandez

1996-01-01

391

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

392

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

393

“The Bigger, the Better”: Challenges in Portraying a Positive Fat Character in Weeds  

Microsoft Academic Search

The author examines the presence of fat stigmatization as well as body acceptance in the hit television Showtime program, Weeds. Through exploring the construction of the character Isabelle Hodes, it is apparent that Weeds works to create a fat-positive character. However, the show's writers also depict several fat-shaming elements when constructing the narrative; fat stigmatization is made most apparent through

Johnanna J. Ganz

2012-01-01

394

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

395

Effects of polyethylene mulch in a short-rotation, poplar plantation vary with weed-control strategies,  

E-print Network

Effects of polyethylene mulch in a short-rotation, poplar plantation vary with weed polyethylene mulch (poly mulch) across a range of site conditions, weed-control treatments and genotypes in a randomized complete-block design (2:4 m Ã? 3 m spacing) during May, 1999, under intensive and minimal weed

Green, Scott

396

Effect of Fertilizer Nitrogen on Weed Emergence and Growth Amy E. Sweeney, Karen A. Renner, Carrie Laboski, and Adam Davis*  

E-print Network

Effect of Fertilizer Nitrogen on Weed Emergence and Growth Amy E. Sweeney, Karen A. Renner, Carrie, emergence, and competitiveness of weeds. Research was conducted to determine the influence of total inorganic soil N (Nit) on the germination, emergence, and growth of five weed species. In a greenhouse

Sims, Gerald K.

397

DOI: 10.1111/j.1365-3180.2012.00915.x Weed interference with field-grown soyabean  

E-print Network

, Canada Summary Rising atmospheric [CO2] is predicted to affect C3 and C4 weed interference with crop was to quantify impacts of eCO2 on C3 and C4 weeds at three levels of biological organisation: individual. This is a Free Air CO2 Enrichment (FACE) experiment. Elevated [CO2] influ- enced weeds at all levels

Sims, Gerald K.

398

A survey of management and economic impact of weeds in dryland cotton cropping systems of subtropical Australia  

Microsoft Academic Search

In dryland cotton cropping systems, the main weeds and effectiveness of management practices were identified, and the economic impact of weeds was estimated using information collected in a postal and a field survey of Southern Queensland and northern New South Wales. Forty-eight completed questionnaires were returned, and 32 paddocks were monitored in early and late summer for weed species and

S. R. Walker; I. N. Taylor; G. Milne; V. A. Osten; Z. Hoque; R. J. Farquharson

2005-01-01

399

Those Nasty Weeds Why Not Control Naturally with Livestock? Contributed by Steve Van Vleet, WSU Whitman County Extension Educator  

E-print Network

Those Nasty Weeds ­ Why Not Control Naturally with Livestock? Contributed by Steve Van Vleet, WSU the restricted use of management tools and the prevalence of undesirable plants or weeds that reduce wildlife impacts of herbicides, is causing landowners to seek alternative weed management strategies. One

Collins, Gary S.

400

Maize Dwarf Mosaic Can Reduce Weed Suppressive Ability of Sweet Corn Martin M. Williams II and Jerald K. Pataky*  

E-print Network

Maize Dwarf Mosaic Can Reduce Weed Suppressive Ability of Sweet Corn Martin M. Williams II prevalent viral disease of sweet corn grown in many regions of North America and Europe. Although some weeds escape control in most sweet corn fields, the extent to which MDM influences the weed suppressive ability

Sims, Gerald K.

401

Mario Barco , Attawan Aramrak, Jared Bell and Ian C. Burke Weed Biology-Biotechnology, Washington State University, Pullman, WA  

E-print Network

Mario Barco , Attawan Aramrak, Jared Bell and Ian C. Burke Weed Biology-Biotechnology, Washington State University, Pullman, WA Introduction Weed control is a top priority to growers, conservationists agricultural output and potential land productivity. Herbicides are used extensively to control weed

Collins, Gary S.

402

Agriculture, Ecosystems and Environment 77 (2000) 193202 Post-dispersal weed seed predation in Michigan crop fields as a function  

E-print Network

Agriculture, Ecosystems and Environment 77 (2000) 193­202 Post-dispersal weed seed predation; accepted 10 June 1999 Abstract Weed seed predation by invertebrates and vertebrates was compared between corn (Zea mays L.) fields within each landscape type. Trials included four common agricultural weed

Landis, Doug

403

Application for CALS-CCE 2012 Summer Internship Title of project: Organic weed management for school grounds  

E-print Network

Application for CALS-CCE 2012 Summer Internship Title of project: Organic weed management the efficacy of organic herbicides versus thermal removal in controlling weeds prevalent on NYS school landscapes. Thermal weeding refers to equipment that delivers intense bursts of heat on plants. Thermal

Keinan, Alon

404

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

Microsoft Academic Search

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

Rodney G. Lym

2005-01-01

405

Control of grass, weeds, and brush is an important cultural practice. Before planting a holly orchard, develop  

E-print Network

Control of grass, weeds, and brush is an important cultural practice. Before planting a holly orchard, develop a weed control strategy that will ensure good plant growth at a minimal cost. Reasons will require extensive control. Asparse grass, weed, or clover cover may require no more than a yearly mowing

Liskiewicz, Maciej

406

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

407

Susceptibility of some weed species to Pepino mosaic virus (PepMV).  

PubMed

The aim of our investigations was to study the susceptibility of 22 weed species to Pepino mosaic virus (PepMV). Seven plants of each species were mechanically inoculated at 4-6 leaf stage with PepMV in a vector free virological glasshouse. Inoculated plants were tested on the basis of symptoms, by DAS ELISA serological method and back inoculation. Among the 22 weed species, only some Solanum ones (S. aethiopicum, S. dulcamara, S. luteum, S. nigrum) were susceptible to PepMV infection. All of them--except S. aethiopicum--belong to Hungarian weed flora, therefore these weeds--occurring mainly in tomato ecosystems--may play important role in the epidemiology of PepMV. Other 18 weed species seemed to be resistant to PepMV, and on the basis of back inoculation not even latent infection has been observed. PMID:16637220

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

2005-01-01

408

Weed suscepts of the potato yellow dwarf virus  

Microsoft Academic Search

Summary  Fifteen new weed suscepts of the potato yellow dwarf virus are reported.\\u000a \\u000a Limited evidence is presented which indicates thatChrysanthemum leucanthemum var.pinnatifidum may be a more important source of the potato yellow dwarf virus under field conditions than Medium Red clover.\\u000a \\u000a \\u000a \\u000a The presence of the yellow dwarf virus was demonstrated in naturally infected plants of the following species:Chrysanthemum leucanthemum var.pinnatifidum, Trifolium

S. G. Younkin

1942-01-01

409

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

E-print Network

~l@rd & :J!j ha~':cl: C Acg e3: Texas College Staiion, Te~as. AGRICUhTURAL AND MECHANICAL COLLEGE OF TEXAS T. 0. WALTON, President - v eac ba* in n "L Phis bulletin contains an account of the separation and lation of the toxic principle of the loco... 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

410

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

411

The influence of short crop rotations on weed community composition  

Microsoft Academic Search

Field experiments were designed to evaluate the effect of crop rotations on weed density and species composition. An 8-year study was initiated in Dotnuva (Lithuania) in 1997 on an Endocalcari-Endohypogleyic Cambisol. Ten crop rotations: peas-winter wheat-sugar beet-spring barley, peas-winter wheat-spring barley, peas-winter wheat-winter wheat, sugar beet-spring barley-winter wheat, sugar beet-peas-winter wheat, sugar beet-spring barley-peas, sugar beet-spring barley-spring rape, peas-winter wheat,

V. Seibutis; I. Deveikyte

412

Volatile metabolites controlling germination in buried weed seeds.  

PubMed

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 O(2) levels and production of volatile metabolites identified as acetaldehyde, ethanol, and acetone. The effectiveness of these compounds in reducing germination was dependent on O(2) levels. PMID:16658159

Holm, R E

1972-08-01

413

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, São 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, João Renato Vaz; Martins, Dagoberto; Cardoso, Leonildo A; Carbonari, Caio Antonio

2005-01-01

414

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

Weed Management Practice Selection Among Midwest U.S. Organic Growers James J. DeDecker, John B of weed management, leading organic farmers to cite weeds as one of the greatest barriers to organic production. Integrated Weed Management (IWM) systems have been developed to address the ecological

Williams, Martin M. II

415

Within-Season Changes in the Residual Weed Community and Crop Tolerance to Interference over the Long Planting Season of Sweet Corn  

E-print Network

Within-Season Changes in the Residual Weed Community and Crop Tolerance to Interference over weeds persisting to harvest (hereafter called residual weeds), and evidence suggests the crop's ability to endure competitive stress from residual weeds (i.e., crop tolerance) is not constant over the planting

Sims, Gerald K.

416

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

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

Keinan, Alon

417

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

418

WEED MANAGEMENT SYSTEMS IN GLUFOSINATE TOLERANT COTTON. P. A. Dotray, J. W. Keeling, D. A. Peters, and J. A. Bond. Texas Agricultural Experiment Station, Texas Agricultural Extension  

E-print Network

WEED MANAGEMENT SYSTEMS IN GLUFOSINATE TOLERANT COTTON. P. A. Dotray, J. W. Keeling, D. A. Peters). The objectives of this research were evaluate weed management systems in glufosinate-tolerant cotton, compare the glufosinate-tolerant cotton weed management system to glyphosate- and bromoxynil-tolerant cotton weed

Mukhtar, Saqib

419

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

420

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

421

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

422

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

423

Remote sensing water observation for supporting Lake Victoria weed management.  

PubMed

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 techniques, and water compounds maps, applying radiative transfer models. The study proposed within the framework of the cooperation between Italian Foreign Affair Ministry (through the University of Rome) and Kenyan Authorities has been carried out on the Kenyan part of the Lake Victoria. This lake is one of the largest freshwater bodies of the world where, over the last few years environmental challenges and human impact have perturbed the ecological balance affecting the biodiversity. The objective of this research study is to define the thematic products, retrievable from satellite images, like weed abundance maps and water compound concentrations. These products, if provided with an appropriate time frequency, are useful to identify the preconditions for the occurrence of hazard events like abnormal macrophyte proliferation and to develop an up-to-date decision support system devoted to an apprised territory, environment and resource management. PMID:18423844

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

2009-05-01

424

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

425

Turfgrass, crop, and weed hosts of Blissus occiduus (Hemiptera: Lygaeidae).  

PubMed

Blissus occiduus Barber is an important pest of buffalograss, Buchloë dactyloides (Nuttall) Engelmann, turf. No-choice studies documented the susceptibility of selected turfgrasses, crops, and weeds to B. occiduus feeding. Highly to moderately susceptible grasses included buffalograss; yellow Setaria glauca (L.) and green foxtail Setaria viridis (L.); Kentucky bluegrass, Poa pratensis L.; perennial ryegrass, Lolium perenne L.; brome, Bromus spp. Leyss.; zoysiagrass, Zoysia japonica Steudel; Bermuda grass, Cynodon dactylon (L.) Pers.; sorghum, Sorghum bicolor (L.) Moench; tall fescue, Festuca arundinacea Schreb.; and barley Hordeum vulgare (L.). Slightly to nonsusceptible grasses included fine fescue, Festuca ovina hirtula L.; rye, Secale cereale L.; crabgrass Digitaria sanguinalis (L.); bentgrass, Agrostis palustris Huds.; wheat, Tritium aestivun L.; corn, Zea mays L.; fall panicum Panicum dichotomiflorum Michx.; and St. Augustinegrass, Stenotaphrum secundatum (Walt.) Kuntze. The reproductive potential of B. occiduus was also investigated on these same grasses. B. occiduus produced offspring on 15 of the 18 turfgrass, crop, and weed species evaluated. No reproduction occurred on either Bermuda grass or St. Augustinegrass, and buffalograss plants were killed by B. occiduus feeding before offspring could be produced. PMID:14998128

Eickhoff, Thomas E; Baxendale, Frederick P; Heng-Moss, Tiffany M; Blankenship, Erin E

2004-02-01

426

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, Jose.; Ribeiro, Angela.

2014-01-01

427

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; Gonzalez-Andujar, Jose Luis

2012-01-01

428

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

429

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

430

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

431

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

432

Weed response to herbicides: regional-scale distribution of herbicide resistance alleles in the grass weed Alopecurus myosuroides.  

PubMed

Effective herbicide resistance management requires an assessment of the range of spatial dispersion of resistance genes among weed populations and identification of the vectors of this dispersion. In the grass weed Alopecurus myosuroides (black-grass), seven alleles of the acetyl-CoA carboxylase (ACCase) gene are known to confer herbicide resistance. Here, we assessed their respective frequencies and spatial distribution on two nested geographical scales (the whole of France and the French administrative district of Côte d'Or) by genotyping 13 151 plants originating from 243 fields. Genetic variation in ACCase was structured in local populations at both geographical scales. No spatial structure in the distribution of resistant ACCase alleles and no isolation by distance were detected at either geographical scale investigated. These data, together with ACCase sequencing and data from the literature, suggest that evolution of A. myosuroides resistance to herbicides occurred at the level of the field or group of adjacent fields by multiple, independent appearances of mutant ACCase alleles that seem to have rather restricted spatial propagation. Seed transportation by farm machinery seems the most likely vector for resistance gene dispersal in A. myosuroides. PMID:16918556

Menchari, Yosra; Camilleri, Christine; Michel, Séverine; Brunel, Dominique; Dessaint, Fabrice; Le Corre, Valérie; Délye, Christophe

2006-01-01

433

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

434

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 & Sgrò 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

435

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

436

Herbicidal agents from actinomycetes against selected crop plants and weeds.  

PubMed

About 64 total actinomycetes were isolated from various coastal soils. Sixteen actinomycete isolates were screened for herbicidal principles. Out of these, five potent isolates were selected for characterisation and identification. Based on their morphological, biochemical and physiological characteristics, the actinomycete isolates were identified as Glyomyces, Saccharomonospra and Streptomyces sp. The Streptomycetes isolates were tested for herbicidal principles by germination inhibition assay. About 10 crop seeds were tested for herbicidal activity with Streptomycetes isolates. The crop seeds did not show growth inhibition. Four weed seeds were tested for herbicidal activity with Streptomyces isolates. Streptomyces inhibits the growth of Echinochilora crusgalli, but it could not inhibit the growth of Echinochilora colonum, Parthenium sp., or Ageratum conizoites. The present study concludes that Streptomyces isolates will be a bioherbicide against E. crusgalli. Further study is required to confirm the activity of Streptomyces isolates against E. crusgalli under field conditions. PMID:20182949

Dhanasekaran, Dharumadurai; Thajuddin, Nooruddin; Panneerselvam, Annamalai

2010-04-01

437

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

438

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

439

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

...Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE...international associations, and other persons for views on the danger of noxious weed dissemination into the United States, or...

2014-01-01

440

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

Code of Federal Regulations, 2013 CFR

...Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE...international associations, and other persons for views on the danger of noxious weed dissemination into the United States, or...

2013-01-01

441

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

442

Phytotoxicity of cardoon (Cynara cardunculus) allelochemicals on standard target species and weeds.  

PubMed

Cardoon (Cynara cardunculus L.) is a native plant to the Iberian Peninsula and the European Atlantic coast and invasive in American environments. Different solvents were used to perform cardoon extracts that were tested in phytotoxic bioassays. The ethyl acetate extract had the highest inhibitory activity so this was tested on the germination and growth of standard target species (lettuce, watercress, tomato, and onion) and weeds (barnyardgrass and brachiaria). The ethyl acetate extract was very active on root growth in both standard target species and weeds and it was therefore fractionated by chromatography. The spectroscopic data showed that the major compounds were sesquiterpene lactones. Aguerin B, grosheimin, and cynaropicrin were very active on etiolated wheat coleoptile, standard target species, and weed growth. The presence of these compounds explains the bioactivity of the ethyl acetate extract. The strong phytotoxicity of these compounds on important weeds shows the potential of these compounds as natural herbicide models. PMID:24974850

Rial, Carlos; Novaes, Paula; Varela, Rosa M; Molinillo, José M G; Macias, Francisco A

2014-07-16

443

Weed Busters: How to take the Kick out of Western Horse Nettle  

E-print Network

Western horse nettle is a weedy perennial in the nightshade family. Ranchers need to control it with herbicides to prevent livestock from ingesting poison that the weed produces. This publication specifies various herbicide options...

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

2007-04-18

444

[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

445

Weeding the Reference Collection: Adapting Current Spaces to Address User Expectations  

E-print Network

a 50% reduction to this collection in order to increase public user and collaborative spaces. The planning process, the criteria used for weeding, the implementation of this project, and its outcomes are described in this poster session...

Devlin, Frances A.; Graves, Kathryn

2009-03-27

446

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

447

The behavior of multiple independent managers and ecological traits interact to determine prevalence of weeds.  

PubMed

Management of damaging invasive plants is often undertaken by multiple decision makers, each managing only a small part of the invader's population. As weeds can move between properties and re-infest eradicated sites from unmanaged sources, the dynamics of multiple decision makers plays a significant role in weed prevalence and invasion risk at the landscape scale. We used a spatially explicit agent-based simulation to determine how individual agent behavior, in concert with weed population ecology, determined weed prevalence. We compared two invasive grass species that differ in ecology, control methods, and costs: Nassella trichotoma (serrated tussock) and Eragrostis curvula (African love grass). The way decision makers reacted to the benefit of management had a large effect on the extent of a weed. If benefits of weed control outweighed the costs, and either net benefit was very large or all agents were very sensitive to net benefits, then agents tended to act synchronously, reducing the pool of infested agents available to spread the weed. As N. trichotoma was more damaging than E. curvula and had more effective control methods, agents chose to manage it more often, which resulted in lower prevalence of N. trichotoma. A relatively low number of agents who were intrinsically less motivated to control weeds led to increased prevalence of both species. This was particularly apparent when long-distance dispersal meant each infested agent increased the invasion risk for a large portion of the landscape. In this case, a small proportion of land mangers reluctant to control, regardless of costs and benefits, could lead to the whole landscape being infested, even when local control stopped new infestations. Social pressure was important, but only if it was independent of weed prevalence, suggesting that early access to information, and incentives to act on that information, may be crucial in stopping a weed from infesting large areas. The response of our model to both behavioral and ecological parameters was highly nonlinear. This implies that the outcomes of weed management programs that deal with multiple land mangers could be highly variable in both space and through time. PMID:23734483

Coutts, Shaun R; Yokomizo, Hiroyuki; Buckley, Yvonne M

2013-04-01

448

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

449

[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

450

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

451

Weed biomass dynamics in planted fallow systems in the humid forest zone of southern Cameroon  

Microsoft Academic Search

Interest in planted fallow systems has focused on soil fertility improvement, neglecting other potential benefits of such\\u000a systems. It is important to quantify other processes responsible for crop yield increases under planted fallows, such as weed\\u000a control. The suppressive potential on weeds of Flemingia macrophylla [(Willd.) Merrill] and Pueraria phaseoloides (Roxb.) Benth, planted fallows was evaluated in field trials in three

Ben Kwaku Banful; Stefan Hauser; Kwadwo Ofori; Frank K. Kumaga

2007-01-01

452

Biomass Production of Weeds in Low-Input and Conventional Cropping of Cereals  

Microsoft Academic Search

Biomass production of weeds under two crop management systems was compared. The conventional system relied on artificial fertilizers and herbicides, and the other was a low-input system incorporating manure as a fertilizer without use of herbicides. A five-year crop rotation comprising rye, oat-pea, barley and two-year grasslands was used in both cropping systems. The air-dried weight of weed species and

T. Hyvönen; J. Salonen

2005-01-01

453

MOISTURE IN DIFFERENT SOIL LAYERS DEPENDING ON WEED DENSITY IN COTTON ???????? ? ?????????? ??????? ?????? ? ?????????? ?? ??????????????? ??? ??????  

Microsoft Academic Search

The main competitors of cotton during the crop production are annual late-spring weeds with some perennial species representing the second most important group. During the 1999-2001 period the effect of 3 main weed species - namely Solanum nigrum L., Amaranthus retroflexus L. and Convolvulus arvensis L. on the soil moisture in 3 layers (0-10, 20-20 and 20-30 cm) was studied

MAYA DIMITROVA; RADA POPOVA; DOCHKA DIMOVA; LENA LALEVA

454

Stooped postures are modified by pretask walking in a simulated weed-pulling task.  

PubMed

Seasonal agricultural workers are hired in some sectors for intermittent manual weed removal, a stoop and grasp harvesting task likely similar to those associated with the high prevalence of musculoskeletal disorders in agriculture. Evaluation of this task in an experimental situation would be useful for identifying and controlling musculoskeletal injury risks, presuming a valid experimental model of the task can be created. The purpose of the present study was to examine how a relevant work-related task, namely prolonged walking, altered the biomechanics of manual weed removal in a laboratory setting. Preliminary field assessments informed the development and analysis of a simulated manual weed removal with two separate conditions: not primed, where 11 participants (4 female, mean age 21.6 years) manually removed a simulated weed six times, and primed, where 23 participants (13 female, mean age 22.1 years) walked 1600 m prior to manually removing the same simulated weed six successive times. Segment end point markers and experimental motion capture were used to determine hip, knee, and ankle angles, as well as toe-target proximity, during weed removal. Significant differences between primed and not primed participants were found for angular displacement at the ankle (t(32) = 5.08, P < .001) and toe-target proximity (t(32) = 2.78, P = .008), where primed participants had increased ankle flexion and a greater distance to the weed, leading to decreased trunk flexion during the harvesting task. These findings suggest that priming can positively influence whole-body postures for manual weed removal. PMID:24417529

Hudson, D S; Copeland, J L; Hepburn, C G; Doan, J B

2014-01-01

455

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

PubMed

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

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

2009-01-01

456

Loss of Glyphosate Efficacy: A Changing Weed Spectrum in Georgia Cotton  

Microsoft Academic Search

Introduction of glyphosate resistance into crops through genetic modification has revolutionized crop protection. Glyphosate is a broad-spectrum herbicide with favorable environmental characteristics and effective broad-spectrum weed control that has greatly improved crop protection efficiency. However, in less than a decade, the utility of this technology is threatened by the occurrence of glyphosate-tolerant and glyphosate-resistant weed species. Factors that have contributed

Theodore M. Webster; Lynn M. Sosnoskie

2010-01-01

457

Biology of a buprestid beetle Sphenoptera clarescens [Col.: Buprestidae] , from skeleton weed, Chondrilla juncea  

Microsoft Academic Search

Investigations carried out in Iran, to discover biological control agents for skeleton weed (Chondrilla juncea L.), showed that the buprestid,Sphenoptera clarescens\\u000a Kerr, was one of the insects highly damaging to the weed. The larvae of this beetle were active throughout theChondrilla season and fed mainly on the rootstocks, causing a progressive decline in naturalChondrilla populations. The host range of the

S. Hasan

1978-01-01

458

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

459

Native weeds and exotic plants: relationships to disturbance in mixed grass prairie  

USGS Publications Warehouse

The paper compares distributions of native weedy species and exotic species with respect to three kinds of disturbance, roads, trails, and prairie dog towns. Data were collected at the north and south units of Theodore Roosevelt National Park and at Wind Cave National Park. The paper concludes that many exotic species differ substantially from native weeds in their exploitation of disturbance. It is thus not useful to manage exotics as if they were just another weed.

Larson, D. L.

2003-01-01

460

Biology, management, and interactions of winter annual weeds and soybean cyst nematode  

Microsoft Academic Search

Certain winter annual weeds have been documented as alternative hosts to soybean cyst nematode (Heterodera glycines Ichinohe; SCN) and growth of such species has become common in no-till production fields in Indiana. Current management systems for SCN include rotation to a non-host crop and use of SCN-resistant soybean [Glycine max (L.) Merr.] varieties but fail to address winter annual weed

Joseph Earl Creech

2007-01-01

461

Weed control in sunflower (helianthus annuus L.) with post-emergent herbicides.  

PubMed

Sunflower is the most important oil crop in Hungary, is the base of the production of cooking oil and moreover takes an important part in production of margarine too. Extracted sunflower groats as a secondary product origining from the mentioned procedure can be used in forage successfully. The amount of harvested sunflower reaches the 20-25% of the EU's yield. The sowing area approaches 500 thousand hectares. The essential condition of successful crop production is the perfect weed control. Sowing areas are infected with monocotyledon and dicotyledonous weeds too. Annual dicotyledonous weeds are the most troublesome. The worst species is the Ambrosia artemisiifolia L. Many other weed species as Abutilon theophrasti MEDIC., Datura stramonium L. and Xanthium strumarium L. can cause serious damages. In our model experiments we examined the herbicide sensibility of two commercial sunflower cultivars as "Iregi szürke csikos", "Marica II" and a sulfonylurea-urea tolerant new hybrid "PR63E82". The experiment was set up under greenhouse conditions with the use of four important weed and different post-emergent herbicide as Modown 4F (bifenox), Pledge 50 WP (flumioxazin) and Granstar 75 DF (tribenuron-methyl). We applied normal and double doses too. Sunflower was cultivated to 4-6 leaf stage. Post-emergent herbicides were sprayed out when weeds were in 2, 2-4 and 4-6 leaf stage. Weed killer and phytotoxic effects of post-emergent herbicides were examined. We declared that development of weeds had significally effect on the effectiveness of different herbicides. PMID:16637218

Béres, I; Szente, D; Gyenes, V; Somlyay, I

2005-01-01

462

Determination of fungal pathogens of common weed species in the vicinity of Tokat, Turkey.  

PubMed

This study was carried out to determine the fungal pathogens on Chenopodium album L., Cirsium arvense (L.) Scop., Convolvulus arvensis L., Cynodon dactylon (L.) Pers., Delphinium consolida L., Portulaca oleracea L., Rumex crispus L., Solanum nigrum L., Sorghum halepense (L.) Pers. and Xanthium strumarium L. which were common weed species of agricultural areas. Surveys were conducted in May-June and August-September in 2004-2005 growing seasons. During the surveys density and frequency of the above mentioned weed species were also determined and number of infected plants was counted in each sampling area. Infected weed samples were collected from each sampling point and brought to the laboratory in polyethylene bags and the pathogens were identified at genus or species level. As a result of two year surveys, ten fungal pathogens were determined on eight weed species. The most important fungal pathogens determined on common weed species were as follow; Peronospora farinosa (Fr.) Fr. on C. album, and Septoria convolvuli DC., Erysiphe convolvuli DC., and Puccinia punctiformis (Strauss) Roehrl. on C. arvensis. These fungal diseases were observed mainly on the weeds located at the borders of fields. Infection rates of these pathogens reached up to 21.2% in some of the survey areas. Further studies should be conducted to evaluate the efficacy of these pathogen under in vitro and in vivo conditions. PMID:21542473

Kadio?lu, I; Karamanli, N; Yanar, Y

2010-01-01

463

[Research on crop-weed discrimination using a field imaging spectrometer].  

PubMed

Discrimination of weeds from crop is the first and important step for variable herbicides application and precise physical weed control. Using a new field imaging spectrometer developed by our group, hyperspectral images in the wavelength range 380-870 nm were taken in the wild for the investigation of crop-weed discrimination. After normalizing the data to reduce or eliminate the influence of varying illuminance, stepwise forward variable selection was employed to select the proper band sets and fisher linear discriminant analysis (LDA) was performed to discriminate crop and weeds. For the case of considering each species as a different class, classification accuracy reached 85% with eight selected bands while for the case of considering overall weed species as a class, classification accuracy was higher than 91% with seven selected bands. In order to develop a low-cost device and system in future, all combinations of two and three bands were evaluated to find the best combinations. The result showed that the best three bands can achieve a performance of 89% comparable to the performance achieved by five bands selected using stepwise selection. The authors also found that "red edge" could afford abundant information in the discrimination of weed and crop. PMID:20827980

Liu, Bo; Fang, Jun-yong; Liu, Xue; Zhang, Li-Fu; Zhang, Bing; Tong, Qing-xi

2010-07-01

464

Remote sensing to monitor monotypic weed patches in semi-arid grasslands  

NASA Astrophysics Data System (ADS)

Remote sensing technology has great potential for mapping weed distributions. Fine-scale weed distribution maps can provide means to evaluate the success of weed control methods, to guide selection of future control methods, and to examine factors that influence the creation and persistence of monotypic weed patches. Here I examined the effectiveness of different classification approaches in detecting dense monotypic patches of the late-phenology weeds Taeniatherum caput-medusae (medusahead) and Aegilops triuncialis (barbed goatgrass), among cool-season forage grasses (Bromus spp. and Avena spp.) across multiple years in semi-arid rangelands in northern California (USA). I found that color infrared photographs acquired at two key phenological periods produced more accurate classifications than those based on one image alone, and that inclusion of training sites did not improve the overall accuracy of a classification. I also examined the association of remnant litter with transitions in species dominance in medusahead, goatgrass or forage patches. Persistence of goatgrass-dominated patches was correlated with the amount of remnant litter present, but surprisingly that of medusahead was not, suggesting a potential need for different strategies in control of these two noxious species. Overall, this study shows that remote sensing can be used to create weed distribution maps of phenologically distinct species, and help us further understand community response to invasion and evaluate the effectiveness of management treatments.

Planck, Laura

465

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

466

[Effects of simulated nitrogen deposition on weeds growth and nitrogen uptake].  

PubMed

In this paper, a greenhouse experiment was conducted to study the responses of different functional groups weeds to simulated nitrogen deposition (4.0 g N.m(-2).yr(-1)). Native weed species Poa annua, Lolium perenne, Avena fatua, Medicago lupulina, Trifolium repens, Plantago virginica, Veronica didyma, Echinochloa crusgalli var. mitis, Eleusine indica and Amaranthus spinosus in orchard ecosystem were used test materials, and their above-and underground biomass and nitrogen uptake were measured. The results showed that under simulated N deposition, the total biomass, shoot biomass and root biomass of all weed species tended increase, while the total biomass was differed for different functional groups of weeds. The biomass of C4 grass, legumes and C3 grass was significantly increased under N deposition, while that of C3 and C4 forbs was not significantly impacted. The root/shoot biomass ratio of Avena fatua and Plantago virginica was enhanced by N deposition, but that of Poa annu, Lolium perenne, Medicago lupulina, Trifolium repens and Amarathus spinosus was not impacted significantly. N deposition had no significant effect on plant N concentration, but significantly enhanced the N uptake of all test weed species except Amarathus spinosus, Poa annua and Veronica didyma. was suggested that the further increase of N deposition might speed up the changes of the community structure weed species due to their different responses to N deposition. PMID:16110678

Jiang, Qiqing; Tang, Jianjun; Chen, Xin; Chen, Jing; Yang, Ruyi; Hu, S

2005-05-01

467

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

468

Fungal pathogens of Euphorbia heterophylla and E. hirta in Brazil and their potential as weed biocontrol agents  

Microsoft Academic Search

A two-year survey of the fungi associated with two important congeneric pantropical weeds, Euphorbia heterophylla and E. hirta, was conducted in part of their native range in southern Brazil. Sampling was concentrated mainly in Rio de Janeiro State\\u000a and ten species were identified as pathogens of these weeds. Two taxa, Botrytis ricini and Uromyces euphorbiae, were common to both weed

Robert W. Barreto; Harry C. Evans

1998-01-01

469

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

470

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

Microsoft Academic Search

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

Carol A. Ellison; Robert W. Barreto

2004-01-01

471

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

PubMed Central

Background and aims Direct seeding of rice is being adopted in rainfed and irrigated lowland ecosystems because it reduces labour costs in addition to other benefits. However, early flooding due to uneven fields or rainfall slows down seed germination and hinders crop establishment. Conversely, early flooding helps suppress weeds and reduces the costs of manual weeding and/or dependence on herbicides; however, numerous weed species are adapted to lowlands and present challenges for the use of flooding to control weeds. Advancing knowledge on the mechanisms of tolerance of flooding during germination and early growth in rice and weeds could facilitate the development of improved rice varieties and effective weed management practices for direct-seeded rice. Principal results Rice genotypes with a greater ability to germinate and establish in flooded soils were identified, providing opportunities to develop varieties suitable for direct seeding in flooded soils. Tolerance of flooding in these genotypes was mostly attributed to traits associated with better ability to mobilize stored carbohydrates and anaerobic metabolism. Limited studies were undertaken in weeds associated with lowland rice systems. Remaining studies compared rice and weeds and related weed species such as Echinochloa crus-galli and E. colona or compared ecotypes of the same species of Cyperus rotundus adapted to either aerobic or flooded soils. Conclusions Tolerant weeds and rice genotypes mostly developed similar adaptive traits that allow them to establish in flooded fields, including the ability to germinate and elongate faster under hypoxia, mobilize stored starch reserves and generate energy through fermentation pathways. Remarkably, some weeds developed additional traits such as larger storage tubers that enlarge further in deeper flooded soils (C. rotundus). Unravelling the mechanisms involved in adaptation to flooding will help design management options that will allow tolerant rice genotypes to adequately establish in flooded soils while simultaneously suppressing weeds. PMID:22957137

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

2012-01-01

472

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

473

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

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

2013-01-01

474

Selenium concentrations of common weeds and agricultural crops grown in the seleniferous soils of northwestern India.  

PubMed

The plants grown in seleniferous soils constitute a major source of toxic selenium levels in the food chain of animals and human beings. Greenhouse and field experiments were conducted to study selenium concentrations of weeds, forages and cereals grown on seleniferous soils located between 31.0417 degrees to 31.2175 degrees N and 76.1363 degrees to 76.4147 degrees E in northwestern India. Eleven winter season (November-April) weed plants were grown in the greenhouse in a soil treated with different levels of selenate-Se. Selenium concentrations of weed plants increased progressively with the levels of selenate-Se in soil. The highest Se concentration was recorded by Silene gallica (246 mgkg(-1)) and the lowest by Avena ludoviciana (47 mgkg(-1)) at 2.5 mg Sekg(-1) soil. A.ludoviciana and Spergula arvensis proved highly tolerant to the presence of 1.25 and 2.5 mg selenate-Sekg(-1) soil and the remaining weeds were sensitive to Se. Dry matter yield of Se-sensitive weed plants was 25 to 62% of the yield in the no-Se control at 1.25mg selenate-Sekg(-1) and 6 to 40% at 2.5mg selenate-Sekg(-1) soil. Other symptoms like change in leaf colour and size, burning of leaf tips and margins, and delayed flowering were also observed due to Se. Dry matter yield of Se-sensitive weed plants expressed as percentage of yield in the no-Se control at both the Se levels was inversely correlated with their Se content (r=-0.731, p<0.01, N=17). Among the weed plants grown in seleniferous soils under field situations, Mentha longifolia accumulated the highest Se (365 mgkg(-1)) and Phalaris minor the lowest (34 mgkg(-1)). Among agricultural crops grown on a naturally contaminated soil in the greenhouse, Se concentrations were the highest for oilseed crops (19-29 mgkg(-1)), followed by legumes (6-13 mgkg(-1)) and cereals (2-18 mgkg(-1)). Helianthus annuus among the oilseed crops, A.ludoviciana among the winter season weeds, M.longifolia among the summer season (May-October) weeds and Cirsium arvense among the perennial weeds can be used for phytoremediation of seleniferous soils as these accumulate the highest amounts of Se. PMID:19800657

Dhillon, Karaj S; Dhillon, Surjit K

2009-12-01

475

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

476

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

PubMed

River valleys represent biologically rich corridors characterized by natural disturbances that create moist and barren sites suitable for colonization by native riparian plants, and also by weeds. Dams and reservoirs interrupt the longitudinal corridors and we hypothesized that this could restrict downstream weed expansion. To consider this "reservoir impediment" hypothesis we assessed the occurrences and abundances of weeds along a 315-km river valley corridor that commenced with an unimpounded reach of the Snake River and extended through Brownlee, Oxbow, and Hells Canyon reservoirs and dams, and downstream along the Snake River. Sampling along 206 belt transects with 3610 quadrats revealed 16 noxious and four invasive weed species. Ten weeds were upland plants, with Canada thistle (Cirsium arvense) restricted to the upstream reaches, where field morning glory (Convolvulus arvensis) was also more common. In contrast, St. John's wort (Hypericum perforatum) was more abundant below the dams, and medusahead wildrye (Taeniatherum caput-medusae) occurred primarily along the reservoirs. All seven riparian species were abundant in the upstream zones but sparse or absent below the dams. This pattern was observed for the facultative riparian species, poison hemlock (Conium maculatum) and perennial pepperweed (Lepidium latifolium), the obligate riparian, yellow nut sedge (Cyperus esculentus), the invasive perennial, reed canary grass (Phalaris arundinacea), and three invasive riparian trees, Russian olive (Elaeagnus angustifolia), false indigo (Amorpha fruticosa), and tamarisk (Tamarix spp.). The hydrophyte purple loosestrife (Lythrum salicaria) was also restricted to the upstream zone. These longitudinal patterns indicate that the reservoirs have impeded the downstream expansion of riparian weeds, and this may especially result from the repetitive draw-down and refilling of Brownlee Reservoir that imposes a lethal combination of drought and flood stress. The dams and reservoirs may also interrupt hydrochory, the downstream flow of seeds and clonal fragments. We thus conclude that with some operational patterns, dams and reservoirs can impede the downstream expansion of riparian weeds. PMID:20945766

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

2010-09-01

477

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

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

2007-01-01

478

BOA detoxification of four summer weeds during germination and seedling growth.  

PubMed

A recent greenhouse study revealed a significant reduction of germination and growth of redroot pigweed (Amaranthus retroflexus) and common purslane (Portulaca oleracea) by rye mulch, whereas velvetleaf (Abutilon theophrasti) and common lambsquarters (Chenopodium album) were not suppressed. Since BOA detoxification by metabolic alteration may influence the relation between the benzoxazinoid content of the soil mulch and weed suppression, we tested the dynamics in BOA detoxification in different plant organs of three and 10-day-old seedlings of four warm season weeds incubated with five BOA concentrations (4, 20, 40, 80, and 200 ?mol g(-1) fresh weight). In addition, germination and length of 3-day-old seedlings were measured after exposure to 0, 0.3, 1.5, 3, 6, and 15 ?mol BOA. Finally, we tested the influence of the MDR translocator inhibitors verapamil, nifedipine, and the GST inhibitor ethycrynic acid on BOA accumulation and detoxification activity. Due to BOA-detoxification, all weeds were able to grow in environments with low BOA contents. At higher contents, Abutilon theophrasti and Chenopodium album had a better chance to survive because of highly active mechanisms that avoided the uptake of BOA (A. theophrasti) and of efficient detoxification activities in youngest seedlings (C. album). The interpretation of all of the data gave the following sequence of increasing sensitivity: A. theophrasti < C. album < P. oleracea ? A. retroflexus. The results were in agreement with recent findings of the suppression of these weeds by rye mulches and their benzoxazinoid contents. Our studies demonstrate for the first time that the detoxification of BOA influences the survival of certain weeds in environments enriched with this allelochemical. Therefore, detoxification processes affect the potential for weed suppression by soil allelochemicals in sustainable weed management. PMID:22614450

Schulz, Margot; Marocco, Adriano; Tabaglio, Vincenzo

2012-07-01

479

Photosensitization in sheep fed Ammi majus (Bishop's weed) seed.  

PubMed

Ammi majus (bishop's weed) grows on the coastal region of southern United States and in other parts of the world. This plant causes severe photosensitization in livestock and probably contributes to the severe photosensitization outbreaks seen in Texas. Sheep were fed finely ground seed of A majus via stomach tube at dose rates of 1, 2, 4, and 8 g/kg of body weight and exposed to sunlight. The single dose of 8 g/kg produced severe clinical signs (in 24 to 48 hours): cloudy cornea, conjunctivokeratitis, photophobia, and edema of the muzzle, ears, and vulva. Daily dosing at 2 and 4 g/kg produced (in 72 to 96 hours) similar signs, whereas the smallest dose (1 g/kg) produced mild irritation of the muzzle. Pathologic changes included (1) corneal edema and marked neutrophilic infiltration of the cornea and corneal/ciliary process, (2) subacute ulcerative and exudative dermatitis of the skin of ears, muzzle, and vulva, and (3) mild focal tubular degeneration (vacuolar type) of the kidney. PMID:564651

Witzel, D A; Dollahite, J W; Jones, L P

1978-02-01

480

Pseudomonas asturiensis sp. nov., isolated from soybean and weeds.  

PubMed

Five strains of gram negative bacteria, isolated from soybean (LPPA 221(T), 222 and 223) and weeds (LPPA 816 and 1442), were analyzed by a polyphasic approach. The isolates showed variation in their phenotypic traits and were placed in the Pseudomonas fluorescens lineage, based on 16S rRNA gene sequence phylogeny, as a single but well separated cluster. MLSA analysis based on gyrB and rpoD sequences clustered the strains in a single branch in the Pseudomonas syringae group, and revealed P. viridiflava as closest relative. DNA-DNA hybridizations showed medium levels of DNA-DNA relatedness with the type strain of P. viridiflava (50%) and lower levels (<32%) with other type strains of the P. syringae group, supporting classification within a novel species of the genus Pseudomonas. The strains can be distinguished from species of the P. syringae group by the fatty acid C17:0 cyclo that is present in a low amount (2.5%) and from P. viridiflava by their inability to assimilate d-tartrate and d-sorbitol, and by the formation of red colonies on TTC medium. For this new species, the name Pseudomonas asturiensis sp. nov. is proposed. The type strain is LPPA 221(T) (=LMG 26898(T)=CECT 8095(T)). PMID:23727430

González, Ana J; Cleenwerck, Ilse; De Vos, Paul; Fernández-Sanz, Ana M

2013-07-01

481

Attachment of the parasitic weed dodder to the host.  

PubMed

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 of host surfaces have yet to be identified. In this study, a battery of microscopy protocols is used to examine the host-parasite interface in an effort to deduce these mechanisms. As the dodder shoot approaches the host tissue, epidermal cells in the parasite shoot elongate and differentiate into secretory type trichomes. The trichome cell walls are malleable, allowing them to elongate towards the host and bend their walls to conform to the shape of the host cell surface. The presence of osmiophilic particles (probable cell-wall-loosening complexes) at far greater numbers than found in other species presages the expansion and malleable nature of the epidermal cells. In addition to the changes in cell shape, the dodder trichome cells secrete an electron-opaque cementing substance that covers the host-parasite interface. When probed with antibodies that recognize cell wall components, the cement reacted only with antibodies that recognize chiefly de-esterified pectins but not other common wall constituents. These data indicate that dodder utilizes both a cementing layer of pectin and a radically modified epidermal cell wall to secure the parasite to the perspective host. PMID:12099223

Vaughn, K C

2002-05-01

482

Aeropollen of weeds of the western United States Gulf Coast.  

PubMed

Volumetric air sampling was performed near Corpus Christi, Texas during all of 1988. The most significant weeds releasing airborne pollen, besides the Asteraceae, were the Amaranthaceae and Chenopodiaceae at 14.8% of total pollen captured, which peaked in September and October. Greater pollen capture (74%) occurred from a peak at 11 PM at a time when inversions are frequent to 9 AM than during the period from late morning to 9 PM. Frequency of amaranth-chenopod pollen capture in the western Gulf Coast region showed no relationship with frequencies along the northern and eastern Gulf Coast nor in eastern North America generally, but rather with western North America where these grains have also been sampled at high levels. As in the West, therefore, amaranth-chenopod aeropollen is sufficiently frequent to be a major source of allergens in the western Gulf Coast region. Other weedy plants, Cannabis/Humulus, Rumex, and the Urticaceae (Parieteria/Urtica) each account for only about 1% of the total annual pollen shed, and consequently they are not nearly as potentially relevant here in pollinosis as are the amaranth-chenopods and Asteraceae. Plantago pollen is very infrequently sampled (less than 0.1%) even though several species are common in the area. Acalypha is newly reported as releasing airborne pollen, a genus related to Mercurialis known to release allergenic pollen in Europe. PMID:1859040

Lewis, W H; Dixit, A B; Wedner, H J

1991-07-01

483

Crop/weed discrimination using near-infrared reflectance spectroscopy (NIRS)  

NASA Astrophysics Data System (ADS)

The traditional uniform herbicide application often results in an over chemical residues on soil, crop plants and agriculture produce, which have imperiled the environment and food security. Near-infrared reflectance spectroscopy (NIRS) offers a promising means for weed detection and site-specific herbicide application. In laboratory, a total of 90 samples (30 for each species) of the detached leaves of two weeds, i.e., threeseeded mercury (Acalypha australis L.) and fourleafed duckweed (Marsilea quadrfolia L.), and one crop soybean (Glycine max) was investigated for NIRS on 325- 1075 nm using a field spectroradiometer. 20 absorbance samples of each species after pretreatment were exported and the lacked Y variables were assigned independent values for partial least squares (PLS) analysis. During the combined principle component analysis (PCA) on 400-1000 nm, the PC1 and PC2 could together explain over 91% of the total variance and detect the three plant species with 98.3% accuracy. The full-cross validation results of PLS, i.e., standard error of prediction (SEP) 0.247, correlation coefficient (r) 0.954 and root mean square error of prediction (RMSEP) 0.245, indicated an optimum model for weed identification. By predicting the remaining 10 samples of each species in the PLS model, the results with deviation presented a 100% crop/weed detection rate. Thus, it could be concluded that PLS was an available alternative of for qualitative weed discrimination on NTRS.

Zhang, Yun; He, Yong

2006-09-01

484

Glyphosate-resistant weeds of South American cropping systems: an overview.  

PubMed

Herbicide resistance is an evolutionary event resulting from intense herbicide selection over genetically diverse weed populations. In South America, orchard, cereal and legume cropping systems show a strong dependence on glyphosate to control weeds. The goal of this report is to review the current knowledge on cases of evolved glyphosate-resistant weeds in South American agriculture. The first reports of glyphosate resistance include populations of highly diverse taxa (Lolium multiflorum Lam., Conyza bonariensis L., C. canadensis L.). In all instances, resistance evolution followed intense glyphosate use in fruit fields of Chile and Brazil. In fruit orchards from Colombia, Parthenium hysterophorus L. has shown the ability to withstand high glyphosate rates. The recent appearance of glyphosate-resistant Sorghum halepense L. and Euphorbia heterophylla L. in glyphosate-resistant soybean fields of Argentina and Brazil, respectively, is of major concern. The evolution of glyphosate resistance has clearly taken place in those agroecosystems where glyphosate exerts a strong and continuous selection pressure on weeds. The massive adoption of no-till practices together with the utilization of glyphosate-resistant soybean crops are factors encouraging increase in glyphosate use. This phenomenon has been more evident in Argentina and Brazil. The exclusive reliance on glyphosate as the main tool for weed management results in agroecosystems biologically more prone to glyphosate resistance evolution. PMID:18161884

Vila-Aiub, Martin M; Vidal, Ribas A; Balbi, Maria C; Gundel, Pedro E; Trucco, Frederico; Ghersa, Claudio M

2008-04-01

485

Use of multicopy transposons bearing unfitness genes in weed control: four example scenarios.  

PubMed

We speculate that multicopy transposons, carrying both fitness and unfitness genes, can provide new positive and negative selection options to intractable weed problems. Multicopy transposons rapidly disseminate through populations, appearing in approximately 100% of progeny, unlike nuclear transgenes, which appear in a proportion of segregating populations. Different unfitness transgenes and modes of propagation will be appropriate for different cases: (1) outcrossing Amaranthus spp. (that evolved resistances to major herbicides); (2) Lolium spp., important pasture grasses, yet herbicide-resistant weeds in crops; (3) rice (Oryza sativa), often infested with feral weedy rice, which interbreeds with the crop; and (4) self-compatible sorghum (Sorghum bicolor), which readily crosses with conspecific shattercane and with allotetraploid johnsongrass (Sorghum halepense). The speculated outcome of these scenarios is to generate weed populations that contain the unfitness gene and thus are easily controllable. Unfitness genes can be under chemically or environmentally inducible promoters, activated after gene dissemination, or under constitutive promoters where the gene function is utilized only at special times (e.g. sensitivity to an herbicide). The transposons can be vectored to the weeds by introgression from the crop (in rice, sorghum, and Lolium spp.) or from planted engineered weed (Amaranthus spp.) using a gene conferring the degradation of a no longer widely used herbicide, especially in tandem with an herbicide-resistant gene that kills all nonhybrids, facilitating the rapid dissemination of the multicopy transposons in a weedy population. PMID:24820021

Gressel, Jonathan; Levy, Avraham A

2014-11-01

486

Discrimination of weeds in brassica crops using optical spectral reflectance and leaf texture analysis  

NASA Astrophysics Data System (ADS)

Optical spectral reflectance and image analysis techniques were investigated as possible solutions to discriminate crop and weed plants. The range of pants included two brassica crop species, a cereal crop and eight weed species. Spectral signatures were obtained form optical reflectance measurement taken with a spectrophotometer in reflectance mode in the region between 700 and 1350 nm. Algorithms were developed based on multivariate statistical analysis of the plant reflectance spectra. By minimizing wavebands of interest for certain crop/weed combinations, better than 95 percent discrimination accuracy was obtained for only two or three waveband measures. Using filters at these wavebands it was possible to easily segregate corp from weed plants in images. Discrimination on the basis of leaf texture was investigated using textural signatures for whole leaves derived from a gray level co-occurrence matrix of nearest- neighbor pixel intensity. Textural features of leaves were expressed in the form of feature vectors comprising nine textural parameters extracted from the co-occurrence matrix. A numerical Bayesian classifier was used to classify leaves based on minimum distance between a mean feature vector determined form a training set and the test feature vector. A mean discrimination accuracy of 90 percent was achieved between al plant species and almost 100 percent separation was achieved between the crop and weeds. The results show that a combination of spectral imaging and texture analysis may provide a robust method of discrimination with potential for real time application.

Favier, John F.; Ross, David W.; Tsheko, R.; Kennedy, Duncan D.; Muir, Andrew Y.; Fleming, John

1999-01-01

487

Host Status of Five Weed Species and Their Effects on Pratylenchus zeae Infestation of Maize.  

PubMed

The host suitability of five of the most common weed species occurring in maize (Zea mays L.) fields in South Africa to Pratylenchus zeae was tested. Based on the number of nematodes per root unit, mealie crotalaria (Crotalaria sphaerocarpa) was a good host; goose grass (Eleusine indica), common pigweed (Amaranthus hybridus), and thorn apple (Datura stramonium) were moderate hosts; and khaki weed (Tagetes minuta) was a poor host. Only the root residues of khaki weed suppressed the P. zeae infestation of subsequently grown maize. When goose grass, khaki weed, and mealie crotalaria were grown in association with maize in soil infested with P. zeae, goose grass and khaki weed severely suppressed maize root development; this resulted in a low number of nematodes per maize root system and a high number of nematodes per maize root unit. Mealie crotalaria did not restrict maize root growth and did not affect nematode densities per maize root system or maize root unit. Special attention should be given to the control of mealie crotalaria, which is a good host for P. zeae, and goose grass, which, in addition to its ability to compete with maize, is also a suitable host for P. zeae. PMID:19290263

Jordaan, E M; De Waele, D

1988-10-01

488

Clover as a cover crop for weed suppression in an intercropping design. I. Characteristics of several clover species  

Microsoft Academic Search

Weeds often form a major problem in weakly competitive vegetable crops, particularly in low input systems. Undersown cover crops can be used to suppress weeds, but often put too high a competitive pressure on the main crop. Cover crop selection is one of the potential means that can be used to design or optimize these intercropping systems. The objective of

Hollander den N. G; L. Bastiaans; M. J. Kropff

2007-01-01

489

The effects of cover crop on weed control in collard (Brassica olerecea var acephala) and lettuce (Lactuca sativa L.).  

PubMed

Leafy vegetables are not very competitive and weed interference can cause considerable yield losses in collard (Brassica olerecea var acephala) and lettuce (Lactuca sativa L.). Currently there are no pre or post emergence herbicides registered for weed control in these vegetables in Turkey. For this reason, alternative weed control strategies need to be developed. Cover crop residue could represent an alternative method of weed management in these crops. Field studies were conducted in 2004 at the Black Sea Agricultural Research Institute experimental field in Samsun, Turkey. The cover crop treatments consisted of Sorghum bicolor (L.) Moench, Sorghum vulgare Pers., Vicia villosa L., Amaranthus cruentus L., Pisum sativum L. and the bare ground with no cover crop. All cover crops were seeded by hand and incorporated into the soil on 11 May, 2004. Each plot was 10 m2 (2 x 5 m) and arranged in a randomized complete block design with four replications. All cover crops were incorporated into the soil by discing on 1 September 2004 at flowering stage of the cover crops. Broadleaved weed species were dominant in the experimental area. Most cover crops established well and S. bicolor biomass was the highest. The number of weed species emerging in all treatments was different at 14 DAD (days after desiccation). Similar results were observed at 28 and 56 DAD. Treatments with Vicia villosa residues had fewer weed species and lower total weed densities than other treatments. PMID:17390812

Mennan, H; Ngouajio, M; Isik, D; Kose, B; Kaya, E

2006-01-01

490

Effects of distance to crop rows and to conspecific neighbours on the size of Brassica napus and Veronica persica weeds  

Microsoft Academic Search

We tested the hypothesis that local competitive conditions are a determinant of the size of individual weeds in cereal crops by investigating the relationship between individual weed size and (a) distance from the crop row and (b) distance to the nearest conspecific neighbour in cereal crops. There were significant but weak effects of distance to rows of summer and winter

Eric J. von Wettberg; Jacob Weiner

2004-01-01

491

Auswirkungen reduzierter Bodenbearbeitung und Vorfrucht auf die Unkrautvegetation Effects of reduced tillage and previous crop on weed vegetation  

Microsoft Academic Search

The reduction of soil tillage intensity is of special interest for organic farmers. To study the influence of reduced tillage on soil properties and weed vegetation field plots were set up in 1992 on the FAM Research farm in southern Germany. From 1999 till 2002 weed vegetation was recorded including soil seed bank, plant density, number of flowering plants and

B. Sprenger

492

Weed control and autumn-olive affect early growth and survival of black walnut in a hardwood clearcut  

Microsoft Academic Search

Eight years after planting in a hardwood clearcut, black walnut trees in plots with weed control had significantly better survival and were taller and larger in diameter than those in plots without weed control. Planting autumn-olive with walnut also significantly increased height and diameter of the walnuts but did not affect their survival.

1988-01-01

493

Analogy potential effects of planting methods and t ank mixed herbicides on wheat yield and weed populations  

Microsoft Academic Search

The aim of integrated weed management (IWM) was to use the combination of different practices to maintain weed densities at manageable levels. A field experiment was conducted at Agricultural College, Tehran of University, in K araj city 2005-2006 by planting wheat, to investigate the response of planting methods and ta nk mixed herbicides. The experiment was laid out using a

S. Sedigheh

2009-01-01

494

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

Microsoft Academic Search

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

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

2009-01-01

495

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

...diseases, noxious farm weeds, and use of pesticides. 222.8 Section 222.8 Parks...diseases, noxious farm weeds, and use of pesticides. (a) Insofar as it involves...and institutions in surveillance of pesticides spray programs; and (3)...

2014-07-01

496

Age structure and growth of the woody legume weed Cytisus scoparius in native and exotic habitats: implications for control  

Microsoft Academic Search

Summary 1. To be successful, integrated weed management (IWM) requires sufficient knowledge of the ecology of the weed and the invaded system to allow prediction of the outcome of control efforts. We studied the age and size structure of both native and exotic popu- lations of Scotch broom Cytisus scoparius to test predictions regarding why it is invasive in exotic

Quentin Paynter; Paul O. Downey; Andrew W. Sheppard

2003-01-01

497

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

Microsoft Academic Search

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

David Kleijn; Leonie A. C. van der Voort

1997-01-01

498

[Effects of labor-saving rice cultivation modes on the diversity of potential weed communities in paddy fields].  

PubMed

Aimed to understand the effects of various labor-saving rice cultivation modes on the diversity of potential weed communities in paddy fields, an investigation was made on the quantitative characteristics of the weed seed bank under dry direct seeding, water direct seeding, seedling throwing, mechanized-transplanting, wheat-rice interplanting, and conventional manual transplanting. Under dry direct seeding, the density of the weed seed bank was up to 228,416 seeds x m(-2), being significantly higher than that under the other five cultivation modes. Wheat-rice interplanting ranked the second place. The seed density of sedge weeds under dry direct seeding and that of broad leaf weeds under wheat-rice interplanting were significantly higher than the seed densities of various kinds of weeds under other cultivation modes. Conventional manual transplanting mode had the highest species richness, with Margalef index being 1.86. The diversity indices, including Shannon-Wiener index, Gini index, and Pielou evenness index under water direct seeding and wheat-rice interplanting were higher than those under other cultivation modes. Comparing with conventional manual transplanting mode, the other five cultivation modes had their own dominant species in the potential weed community, and thereby, different labor-saving rice cultivation modes should be applied by turns to control the potential weed community in paddy fields effectively and persistently. PMID:20077702

Li, Shu-Shun; Qiang, Sheng; Jiao, Jun-Sen

2009-10-01

499

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

Microsoft Academic Search

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

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

2006-01-01

500

Yield components and quality of rice in response to graminaceous weed density and rice stink bug populations  

Microsoft Academic Search

Field experiments were conducted in 2002 and 2003 to investigate weed density, its relationship to rice stink bug (Oebalus pugnax, F.) populations, and damage to rice caused by stink bugs. Graminaceous weeds examined were barnyardgrass, Echinochloa crus-galli Beauv., Amazon sprangletop, Leptochloa panicoides (Presl.) Hitchc., broadleaf signalgrass, Brachiaria platyphylla Nash., and large crabgrass, Digitaria sanguinalis, (L.). Rice seed weight, percent filled

K. V. Tindall; B. J. Williams; M. J. Stout; J. P. Geaghan; B. R. Leonard; E. P. Webster

2005-01-01