scholarly journals Control of Conyza spp. with glyphosate – a review of the situation in Europe

2013 ◽  
Vol 49 (No. 1) ◽  
pp. 44-53 ◽  
Author(s):  
M. Sansom ◽  
A.A. Saborido ◽  
M. Dubois
Keyword(s):  
Weed Management ◽  
Management Strategies ◽  
Agricultural Practices ◽  
Current Control ◽  
Weed Species ◽  
Resistance Development ◽  
Perennial Crops ◽  
Herbicide Resistant ◽  
Sublethal Doses

In Europe, glyphosate resistant populations have developed in some weed species in perennial crops, including three species of the genus Conyza documented by the International Survey of Herbicide Resistant Weeds. Conyza spp. biology is reviewed in this paper and related to population dynamics and the development of resistant populations. Suboptimal growth stage at application, improper agricultural practices such as overreliance on glyphosate and long-term use of sublethal doses are identified as the most important factors of resistance development. Current control methods in perennial crops including mixtures of glyphosate with other active ingredients are discussed and effective weed management strategies are described to manage the development and spread of glyphosate resistant Conyza spp. in Europe.

scholarly journals A Review of the Soil Seedbank from a Weed Scientists Perspective

Agronomy ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 369 ◽  
Author(s):  
Lauren M. Schwartz-Lazaro ◽  
Josh T. Copes
Keyword(s):  
Weed Management ◽  
Weed Species ◽  
Short Term ◽  
Management Options ◽  
Herbicide Resistant ◽  
The Past ◽  
Weed Seeds ◽  
Soil Seedbank ◽  
Management Tactics

Despite efforts to eliminate weeds, they continue to thrive. Weed persistence is reliant upon the soil seedbank. Knowledge of the soil seedbank is continually expanding, but with the rising threat of herbicide-resistant weeds in agriculture, weed scientists have, in the past, focused their management tactics to more short-term solutions that tackle the aboveground problems, rather than long-term solutions. This article summarized the soil seedbank dynamics of weed seeds and derives management options, from a North American weed scientists’ perspective, that (i) favor the depletion of the seedbank, (ii) favor the germination of the seedbank, and (iii) reduce the possibilities of seed produced by the seedlings that germinated to return the soil. These options can potentially deter herbicide resistance and are successful in the short term for reducing field weed infestations, but are likely to take many years to affect recruitment to the weed seedbank, including recruitment of weed species with a high risk for resistance. The natural longevity of the seedbank suggests that alternative or additional weed management tactics are required to reduce the store of weed seeds in the active seedbank.

scholarly journals Rice Ecosystem, Allelopathy and Environment – A Review

2013 ◽  
Vol 11 (1) ◽  
pp. 112-121 ◽  
Author(s):  
AB Siddique ◽  
BS Ismail
Keyword(s):  
Weed Management ◽  
Resource Competition ◽  
Management Strategies ◽  
Growth And Yield ◽  
Weed Species ◽  
Herbicide Resistant ◽  
Evolution Of Resistance ◽  
Weed Infestation ◽  
Repeated Use ◽  
Rice Ecosystem

Allelopathy is an important factor which contributes in determining distribution of species and their abundance within communities. Plant-plant interference is the combined effect of allelopathy, resource competition, and many other factors. Weed infestation is a major problem limiting the growth and yield of rice. Synthetic herbicide has been used for over 50 years as the prime source of weed control. The repeated use of herbicides in rice has already led to the evolution of resistance in some weed species. The conventional synthetic herbicides are becoming less effective against the resistant weed biotypes. Due to increase in the number of herbicide-resistant weeds and environmental concerns in the use of synthetic herbicides, allelopathy has been gaining preference as one of the considerable efforts in designing alternative weed management strategies. Modern ecotoxicologists and allelopathy researchers have been trying to identify allelochemicals to use as biodegradable pesticide. Two allelochemicals have been discovered, namely hexanedioic acid dioctyl ester and di-n-octyl phthalate which can be used as biopesticide. However, still there is enough scope to conduct such research that will contribute to protect our environment as well as increase food safety. DOI: http://dx.doi.org/10.3329/agric.v11i1.15251 The Agriculturists 2013; 11(1) 112-121

scholarly journals Conservation Agriculture: An Eco-Friendly System of Weed Management in Field Crops

2014 ◽  
Vol 3 (4) ◽  
pp. 91-100
Author(s):  
Tika Bahadur Karki ◽  
Jiban Shrestha
Keyword(s):  
Weed Management ◽  
Management Strategies ◽  
Conservation Agriculture ◽  
Grass Species ◽  
Weed Species ◽  
Conventional Agriculture ◽  
Perennial Weeds ◽  
Weed Dynamics ◽  
Agriculture Systems

Since the conservation agriculture (CA) is spreading across the globe, information on weed dynamics and their management under CA is needed. Here, an attempt has been made to summarize the recent research on weed dynamics and their management aspects in the CA systems. Changes in patterns of tillage, planting systems, and other management strategies can alter the soil environment and lead to shifts in weed populations. Weed patterns and populations are not always stable but vary with location, crop, and herbicides use. However, in many long-term conservation management studies, a general increase in perennial weeds and grass species has been observed. No tillage increased the weed population during first season and there after decreased. Residue has significantly reduced the number of weed species and population compared to conventional agriculture systems. The development of low-dose of non-selective pre and selective post emergence herbicides, and transgenic crops has greatly improved the feasibility of CA systems.DOI: http://dx.doi.org/10.3126/ije.v3i4.11733 International Journal of Environment Volume-3, Issue-4, Sep-Nov 2014Page: 91-100

No-tillage adoption decisions in southern Australian cropping and the role of weed management

2006 ◽  
Vol 46 (4) ◽  
pp. 563 ◽  
Author(s):  
F. H. D'Emden ◽  
R. S. Llewellyn
Keyword(s):  
Herbicide Resistance ◽  
Weed Management ◽  
Management Strategies ◽  
No Tillage ◽  
Long Term Effects ◽  
Herbicide Resistant ◽  
Increased Risk ◽  
System Use

Adoption of no-tillage sowing systems has increased rapidly in many Australian grain growing regions over the past decade. The extent of herbicide resistant weed populations in these regions has also increased over the same period. A survey of growers in the South and Western Australian cropping regions was conducted to identify opportunities for more effective tillage and weed-related extension. Trends in sowing system use are determined, as are growers’ perceptions of the long-term effects of no-tillage on herbicide costs, herbicide resistance, and soil erosion. The results suggest a major expansion in the adoption of no-tillage sowing in most South Australian cropping regions over the next 5 years, although growers expect increased herbicide costs in no-tillage systems and an increased risk of herbicide resistance. Herbicide resistance and weed control issues are the main reasons given for reducing no-tillage use. A key research and extension challenge is to develop and implement weed management strategies that are able to sustain long-term no-tillage use in a cropping environment where growers place a high value on the soil and production benefits of no-tillage, but over-reliance on herbicides can rapidly lead to resistance in major crop weeds.

scholarly journals Effects of Narrow-Windrow Burning on Weed Dynamics in Soybean in Louisiana

2021 ◽  
Vol 3 ◽  
Author(s):  
Katie M. Patterson ◽  
Lauren M. Schwartz-Lazaro ◽  
Gabrielle LaBiche ◽  
Daniel O. Stephenson
Keyword(s):  
Weed Management ◽  
Management Practices ◽  
Production Systems ◽  
Management Strategies ◽  
Weed Seed ◽  
Weed Species ◽  
Cultural Management ◽  
Soil Seedbank ◽  
Weed Dynamics

The soil seedbank allows for long-term persistence of weed species in agricultural fields. Some weed species can persist in the soil seedbank for extended periods. Restricting inputs into the weed seedbank has a large impact on future population density and influences management practices of these weeds in soybean production systems. Harvest weed seed control (HWSC) tactics incorporate mechanical and cultural management strategies to target weed seeds present at harvest. A 3-year trial was initiated to determine if continual use of the HWSC method, narrow windrow burning, selects for earlier seed set and shattering in Louisiana soybean. No shifts in weed populations or shattering time were observed. However, there was a significant reduction in weed density and the weed seed present in the soil seedbank when HWSC and robust herbicide programs were used in combination. Therefore, utilizing multiple effective weed management strategies is imperative in reducing the soil seedbank.

scholarly journals Weeds Hosting the Soybean Cyst Nematode (Heterodera glycines Ichinohe): Management Implications in Agroecological Systems

Agronomy ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 146
Author(s):  
Leonardo F. Rocha ◽  
Karla L. Gage ◽  
Mirian F. Pimentel ◽  
Jason P. Bond ◽  
Ahmad M. Fakhoury
Keyword(s):  
Weed Management ◽  
Soybean Cyst Nematode ◽  
Heterodera Glycines ◽  
Integrated Management ◽  
Cropping System ◽  
Cyst Nematode ◽  
Weed Species ◽  
Initial Inoculum ◽  
Herbicide Resistant ◽  
Sites Of Action

The soybean cyst nematode (SCN; Heterodera glycines Ichinohe) is a major soybean-yield-limiting soil-borne pathogen, especially in the Midwestern US. Weed management is recommended for SCN integrated management, since some weed species have been reported to be hosts for SCN. The increase in the occurrence of resistance to herbicides complicates weed management and may further direct ecological–evolutionary (eco–evo) feedbacks in plant–pathogen complexes, including interactions between host plants and SCN. In this review, we summarize weed species reported to be hosts of SCN in the US and outline potential weed–SCN management interactions. Plants from 23 families have been reported to host SCN, with Fabaceae including most host species. Out of 116 weeds hosts, 14 species have known herbicide-resistant biotypes to 8 herbicide sites of action. Factors influencing the ability of weeds to host SCN are environmental and edaphic conditions, SCN initial inoculum, weed population levels, and variations in susceptibility of weed biotypes to SCN within a population. The association of SCN on weeds with relatively little fitness cost incurred by the latter may decrease the competitive ability of the crop and increase weed reproduction when SCN is present, feeding back into the probability of selecting for herbicide-resistant weed biotypes. Therefore, proper management of weed hosts of SCN should be a focus of integrated pest management (IPM) strategies to prevent further eco–evo feedbacks in the cropping system.

scholarly journals Interactions of Nitrogen Source and Rate and Weed Removal Timing Relative to Nitrogen Content in Corn and Weeds and Corn Grain Yield

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Alexandra M. Knight ◽  
Wesley J. Everman ◽  
David L. Jordan ◽  
Ronnie W. Heiniger ◽  
T. Jot Smyth
Keyword(s):  
Grain Yield ◽  
Weed Management ◽  
Management Strategies ◽  
Field Studies ◽  
Weed Species ◽  
Weed Interference ◽  
Coated Urea ◽  
N Fertility ◽  
Corn Grain ◽  
Corn Grain Yield

Adequate fertility combined with effective weed management is important in maximizing corn (Zea mays L.) grain yield. Corn uptake of nitrogen (N) is dependent upon many factors including weed species and density and the rate and formulation of applied N fertilizer. Understanding interactions among corn, applied N, and weeds is important in developing management strategies. Field studies were conducted in North Carolina to compare corn and weed responses to urea ammonium nitrate (UAN), sulfur-coated urea (SCU), and composted poultry litter (CPL) when a mixture of Palmer amaranth (Amaranthus palmeri S. Wats.) and large crabgrass (Digitaria sanguinalis L.) was removed with herbicides at heights of 8 or 16 cm. These respective removal timings corresponded with 22 and 28 days after corn planting or V2 and V3 stages of growth, respectively. Differences in N content in above-ground biomass of corn were noted early in the season due to weed interference but did not translate into differences in corn grain yield. Interactions of N source and N rate were noted for corn grain yield but these factors did not interact with timing of weed control. These results underscore that timely implementation of control tactics regardless of N fertility management is important to protect corn grain yield.

Weed Problems in Uruguayan Agriculture: Evolution and Current Situation

2021 ◽  
Vol 32 (5) ◽  
pp. 203-207
Author(s):  
M. Alejandro Garcia ◽  
Lucia V. Meneses ◽  
Tiago Edu Kaspary
Keyword(s):  
Weed Management ◽  
Agricultural Production ◽  
Production Systems ◽  
Integrated Weed Management ◽  
Zero Tillage ◽  
Weed Species ◽  
Management Tools ◽  
Herbicide Resistant ◽  
Species Frequencies ◽  
Agricultural Production Systems

Uruguayan agriculture has undergone dramatic changes in the last 50 years driven by the adoption of new agricultural production systems that incorporate zero tillage and herbicide resistant crops. This has resulted in a shift in weed species frequencies and the dispersion of introduced herbicide resistant weed populations. Finally, integrated weed management tools are being developed by research and extension services to manage herbicide-resistant (HR) weeds better and to reduce environmental impact of herbicides.

Model of rice (Oryza sativa) yield reduction as a function of weed interference

Weed Science ◽  
1997 ◽  
Vol 45 (2) ◽  
pp. 218-224 ◽  
Author(s):  
Karl W. VanDevender ◽  
Thomas A. Costello ◽  
Roy J. Smith
Keyword(s):  
Weed Management ◽  
Management Strategies ◽  
Economic Assessment ◽  
Richards Equation ◽  
Yield Reduction ◽  
Published Data ◽  
Weed Species ◽  
Individual Parameter ◽  
Alternative Weed Control ◽  
Parameter Values

Economic assessment of weed management strategies in rice is dependent upon a quantitative estimate of the yield impact of a given weed population. To assist rice producers in making such assessments, a mathematical model was developed to predict rice yield reduction as a function of weed density and duration of interference. The nonlinear empirical model was a unique 3-dimensional adaptation of the Richards equation with 4 parameters. Using published data, individual parameter values were fitted for each of 6 weed species interfering with either conventional or semi-dwarf statured rice cultivars. The functional form of the equation produced surfaces that were qualitatively consistent with available data and experience regarding rice-weed biology. Hence, predictions from the model should be useful and reliable in assessing the economic impact of weeds and in determining the feasibility of alternative weed control treatments for various field scenarios.

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