Herbicide Resistance: Where are we? How did we Get here? Where are we Going?

The first significant cases of herbicide-resistant weed populations were to the triazines in the 1970s. In the last 10 years there has been an increase in the number of weed populations that have become resistant to an array of herbicides. In some of these cases, like rigid ryegrass in Australia, a multitude of resistant biotypes has evolved with different mechanisms of resistance. If the present trend continues, the number of herbicides effective on certain weed species may diminish rapidly. To counteract this trend, industry has organized a number of intercompany working groups to specifically address the development of resistance and to implement plans to manage resistance. University and extension along with industry personnel across the world have begun educating growers on resistance management. However, this effort needs to be intensified to find new solutions for controlling weeds through the use of integrated weed management practices that incorporate new and established herbicides with cultural, mechanical, and biological control methods. The challenge is to develop cost effective, environmentally sustainable programs for weed control while maintaining the present efficiency in food and fiber production so that needs of an ever expanding human population can be met.

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Grain grower perceptions and use of integrated weed management

Australian Journal of Experimental Agriculture ◽

10.1071/ea03115 ◽

2004 ◽

Vol 44 (10) ◽

pp. 993 ◽

Cited By ~ 55

Author(s):

R. S. Llewellyn ◽

R. K. Lindner ◽

D. J. Pannell ◽

S. B. Powles

Keyword(s):

Weed Control ◽

Weed Management ◽

Management Practices ◽

Economic Value ◽

Cost Effective ◽

Farming System ◽

Integrated Weed Management ◽

Management Decision ◽

Herbicide Resistant ◽

Management Decision Making

Greater adoption of integrated weed management, to reduce herbicide reliance, is an objective of many research and extension programmes. In Australian grain-growing regions, integrated weed management is particularly important for the management of herbicide resistance in weeds. In this study, survey data from personal interviews with 132 Western Australian grain growers are used to characterise the use and perceptions of integrated weed management practices. The main objective was to identify opportunities for improved weed management decision making, through targeted research and extension. The extent to which integrated weed management practices are used on individual farms was measured. Perceptions of the efficacy and reliability of various weed management practices were elicited for control of annual ryegrass (Lolium rigidum Gaud.), along with perceptions of the economic value of integrated weed management practices relative to selective herbicides. All growers were shown to be using several integrated weed management practices, although the use of some practices was strongly associated with the presence of a herbicide-resistant weed population. In general, both users and non-users were found to have high levels of awareness of integrated weed management practices and their weed control efficacy. Herbicide-based practices were perceived to be the most cost-effective. Opportunities for greater adoption of integrated weed management practices, to conserve the existing herbicide resource, exist where practices can be shown to offer greater shorter-term economic value, not necessarily just in terms of weed control, but to the broader farming system.

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Effects of crop rotation and field management methods on weed density and species composition in the southeastern part of Latvia

Environment Technology Resources Proceedings of the International Scientific and Practical Conference ◽

10.17770/etr2015vol2.275 ◽

2015 ◽

Vol 2 ◽

pp. 235

Author(s):

Jevgenija Ņečajeva ◽

Zane Mintāle ◽

Ieva Dudele ◽

Anda Isoda-Krasovska ◽

Jolanta Čūrišķe ◽

...

Keyword(s):

Species Composition ◽

Weed Control ◽

Crop Rotation ◽

Weed Management ◽

Management Practices ◽

Integrated Weed Management ◽

Weed Species ◽

Southeastern Part ◽

Weed Density ◽

Field Management

Integrated weed management (IWM) is a complex approach to weed control that is based on use of several different methods complementing each other, instead of relying on one single method, like chemical weed control. Weed control methods that can be used as parts of IWM strategy include mechanical weed control, application of herbicides, low tillage, changes in the rate and application time of fertilizers, use of undersown crops and crop rotation. Weed surveys were carried out in 2013 and 2014 in the southeastern part of Latvia. The aim of this study was to assess the effect of crop rotation and other field management practices on weed density and weed species composition using the data collected in the surveys. Survey was carried out in the arable fields of conventional farms within four different size categories. One of the significant factors that explained the variation of weed composition within a field was a proportion of cereals in crop rotation within a four year period. Further surveys are required to estimate the effects of climatic variables. Density-dependence can also be important for practical management decisions for particular weed species and should be investigated.

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Weed management practices in Argentina crops

Weed Technology ◽

10.1017/wet.2019.26 ◽

2019 ◽

Vol 33 (03) ◽

pp. 459-463 ◽

Cited By ~ 5

Author(s):

Julio Alejandro Scursoni ◽

Alejandra Carolina Duarte Vera ◽

Fernando Hugo Oreja ◽

Betina Claudia Kruk ◽

Elba Beatriz de la Fuente

Keyword(s):

Weed Management ◽

Crop Production ◽

Management Practices ◽

Integrated Weed Management ◽

Weed Species ◽

Chemical Application ◽

Modes Of Action ◽

The People ◽

Herbicide Timing ◽

Narrow Row

AbstractData from surveys are used to help quantitatively diagnose the relative importance of chemical and nonchemical management practices, identify weed problems, and provide potential solutions. However, to our knowledge, such surveys have not been conducted in Argentina. In 2016, advisors and crop producers from cropping areas across Argentina were surveyed through email with the objectives to identify the main weed species problems and assess the use of chemical and nonchemical weed management practices in different crop production areas in Argentina. Fleabane, pigweed, johnsongrass, fingergrass, goosegrass, barnyardgrass, and ryegrass were considered the most important weeds. More than 53% of the producers used only chemical options; 86% used chemical fallow (i.e., keeping weed free with chemical application); 62% used full herbicide rates; 46% used proper herbicide timing; 41% used multiple modes of action; and 32% used rotation of herbicide modes of action. The main nonchemical practices used were crop rotation (45%); avoiding seed production during (31%) and after (25%) the crop cycle; narrow row spacing (19%); and cultivars with greater competitive ability (18%). Less than 15% of the people surveyed used increased crop densities or altered date of sowing. There is a high dependence on chemical control in the main crops grown in Argentina. Extension efforts are needed to emphasize the importance of integrated weed management.

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Weed Management in New Zealand Pastures

Agronomy ◽

10.3390/agronomy9080448 ◽

2019 ◽

Vol 9 (8) ◽

pp. 448 ◽

Cited By ~ 7

Author(s):

Hossein Ghanizadeh ◽

Kerry C. Harrington

Keyword(s):

New Zealand ◽

Weed Management ◽

Management Strategies ◽

Cost Effective ◽

Integrated Weed Management ◽

Meat Production ◽

Weed Species ◽

Pasture Management ◽

Pasture Production ◽

Important Approach

In New Zealand, pastoral farming for dairy and meat production is the major land use. As with any agricultural production system, weeds are a threat to efficient pasture production in New Zealand. In this review, we outline the problems caused by weeds in New Zealand pastures, and the management strategies being used to control them. There are currently 245 plant species from 40 plant families that are considered to be troublesome weeds in New Zealand pastures. The application of herbicides is an important approach to manage weeds in New Zealand pastures; however, a key to the success of these pastures is the use of clovers in combination with the grasses, so the challenge is to find herbicides that selectively control weeds without damaging these legumes. The use of spot spraying and weed wiping are often required to ensure selective control of some weed species in these pastures. Non-chemical agronomic approaches such as grazing management and using competitive pasture species often play a more important role than herbicides for weed management in many New Zealand pastures. Thus, integrated weed management using a combination of herbicides and good pasture management strategies leads to the most cost-effective and efficient control of pasture weeds in New Zealand.

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Herbicide-Resistant Weeds: Management Tactics and Practices

Weed Technology ◽

10.1614/wt-05-084r1.1 ◽

2006 ◽

Vol 20 (3) ◽

pp. 793-814 ◽

Cited By ~ 205

Author(s):

Hugh J. Beckie

Keyword(s):

Herbicide Resistance ◽

Weed Management ◽

Management Practices ◽

Cropping Systems ◽

Integrated Weed Management ◽

Weed Species ◽

Herbicide Resistant ◽

Application Rates ◽

Selection For ◽

Reactive Management

In input-intensive cropping systems around the world, farmers rarely proactively manage weeds to prevent or delay the selection for herbicide resistance. Farmers usually increase the adoption of integrated weed management practices only after herbicide resistance has evolved, although herbicides continue to be the dominant method of weed control. Intergroup herbicide resistance in various weed species has been the main impetus for changes in management practices and adoption of cropping systems that reduce selection for resistance. The effectiveness and adoption of herbicide and nonherbicide tactics and practices for the proactive and reactive management of herbicide-resistant (HR) weeds are reviewed. Herbicide tactics include sequences and rotations, mixtures, application rates, site-specific application, and use of HR crops. Nonherbicide weed-management practices or nonselective herbicides applied preplant or in crop, integrated with less-frequent selective herbicide use in diversified cropping systems, have mitigated the evolution, spread, and economic impact of HR weeds.

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Performance of Weeder in Mechanically Transplanted Rice Cultivation

Bangladesh Rice Journal ◽

10.3329/brj.v22i1.41833 ◽

2019 ◽

Vol 22 (1) ◽

pp. 25-34

Author(s):

AKMS Islam ◽

MA Hossen ◽

MKA Bhuiyan ◽

MM Islam ◽

MA Rahman

Keyword(s):

Weed Management ◽

Management Practices ◽

Field Performance ◽

Field Capacity ◽

Cost Effective ◽

Weed Species ◽

Wet Season ◽

Transplanted Rice ◽

Silty Loam ◽

Hand Weeding

Field performance of low land weeder was evaluated in mechanically transplanted rice fieldat Bahirbagh and Provakordi representing the silty loam soil under Gopalganj district of Bangladesh during the non-irrigated wet season (Aman) 2016. Twenty-one-day-old seedlings were transplanted by walk behind type 4-rows mechanical rice transplanter (DP480) at a pre-set spacing of 300 × 170 mm. Randomized Complete Block (RCB) design with three replications was applied with weeding practices of BRRI weeder (BW) followed by (fb) one hand weeding (HW), BRRI power weeder (BPW) fb one HW, two HW, pyrazosulfuron-ethyl (PSE) fb one HW, weedy check, weed free and mulching fb two HW (farmers’ practice) in two locations. The common weed species were observed in experimental sites. Weeding efficiency (WE) of BPW and BW was 67 and 44, respectively. Field capacity of BPW and BW was obtained 0.07 and 0.03 ha hr-1, respectively. Operator’s skill influenced the performance of weeder. During operation, BPW damaged 14-15% tillers in both the locations. However, damaged plants were revived after few days. The labour requirement in BW fb one HW, BPW fb one HW, PSE fb one HW and two HW were 380, 362, 243 and 616 man-hr ha-1 respectively. Except weedy check, weed management practices showed identical grain yield in both the locations. The BCR was accounted in PSE fb one HW (1.35), BW fb one HW (1.21), BPW fb one HW (1.20) whereas the lowest BCR was observed in weedy (0.83) and two HW (1.00). It can be concluded that pyrazosulfuron-ethyl, BRRI power weeder followed by one hand weeding and BRRI weeder followed by one hand weeding appeared as the cost effective weed control methods in mechanically transplanted Aman rice production. Bangladesh Rice j. 2018, 22(1): 25-34

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Upgrading the RIM Model for Improved Support of Integrated Weed Management Extension Efforts in Cropping Systems

Weed Technology ◽

10.1614/wt-d-14-00020.1 ◽

2014 ◽

Vol 28 (4) ◽

pp. 703-720 ◽

Cited By ~ 13

Author(s):

Myrtille Lacoste ◽

Stephen Powles

Keyword(s):

Herbicide Resistance ◽

Weed Management ◽

Cropping Systems ◽

Integrated Management ◽

Integrated Weed Management ◽

Weed Species ◽

Management Options ◽

Rigid Ryegrass ◽

And Control

RIM, or “Ryegrass Integrated Management,” is a user-friendly weed management software that integrates long-term economics. As a model-based decision support system, RIM enables users to easily build 10-year cropping scenarios and evaluate the impacts of management choices on annual rigid ryegrass populations and long-term profitability. Best used in a workshop format to enable learning through interactions, RIM can provide insights for the sustainable management of ryegrass through “what-if” scenarios in regions facing herbicide resistance issues. The upgrade of RIM is presented, with changes justified from an end-user perspective. The implementation of the model in a new, intuitive software format is presented, as well as the revision, update, and documentation of over 40 management options. Enterprises, establishment systems, and control options were redefined to represent current practices, with the notable inclusion of customizable herbicide options and techniques for weed seed control at harvest. Several examples of how RIM can be used with farmers to demonstrate the benefits of adopting recommended practices for managing or delaying the onset of herbicide resistance are presented. Originally designed for the dryland broadacre systems of the Australian southern grainbelt, RIM's underlying modeling was restructured to facilitate future updates and adaptation to other weed species and cropping regions.

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Responses of Rice Flatsedge (Cyperus iria) and Barnyardgrass (Echinochloa crus-galli) to Rice Interference

Weed Science ◽

10.1614/ws-d-09-00050.1 ◽

2010 ◽

Vol 58 (3) ◽

pp. 204-208 ◽

Cited By ~ 25

Author(s):

Bhagirath S. Chauhan ◽

David E. Johnson

Keyword(s):

Weed Management ◽

Management Practices ◽

Stem Elongation ◽

Weight Ratio ◽

Stem Length ◽

Integrated Weed Management ◽

Shoot Biomass ◽

Weed Species ◽

Complete Control ◽

Crop Density

Rice flatsedge and barnyardgrass are widespread and competitive weeds in direct-seeded rice. Developing integrated weed management strategies that elevate suppression of weeds by rice through crop density, nutrition, and cultivar choice requires better understanding of the extent to which rice interferes with the growth of these weeds and how these species respond to resource limitation with crop interference. Rice interference reduced the height of barnyardgrass but did not affect height of rice flatsedge. These weed species were able to grow taller than rice and thus avoided being shaded. Increased specific stem length under crop interference may demonstrate a strategy of stem elongation to allow the top portion of the weeds to be kept out of shade. Rice interference reduced inflorescence and shoot biomass of both weed species. Barnyardgrass showed the ability to reduce the effects of rice interference by increasing leaf weight ratio. The present study shows that crop interference alone may reduce weed growth but may not give complete control of these weed species. This highlights the need for the integration of management practices to achieve control of these weed species.

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Integrated weed management practices and sustainable food production among farmers in Kwara State, Nigeria

Open Agriculture ◽

10.1515/opag-2021-0221 ◽

2021 ◽

Vol 6 (1) ◽

pp. 124-134

Author(s):

Emmanuel Oyamedan Imoloame ◽

Ibrahim Folorunsho Ayanda ◽

Olayinka Jelili Yusuf

Keyword(s):

Weed Management ◽

Food Production ◽

Management Practices ◽

Sampling Technique ◽

Structured Interview ◽

Integrated Weed Management ◽

Sustainable Food ◽

Arable Crops ◽

Multi Stage ◽

Self Sufficiency

Abstract A survey was conducted in the Kwara State of Nigeria to study the integrated weed management (IWM) practices by farmers. This was in view of the poor weed management practices adopted by farmers, which is a major factor responsible for low yields of many arable crops in Kwara State. A multi-stage sampling technique was used to select a sample size of 480 respondents, and a structured interview schedule was used to elicit information from them. Data obtained were analyzed using descriptive statistics. Factor analysis was also carried out to examine the perception of farmers’ benefits of IWM. Results showed that the majority of farmers (29.4%) were youths, married (89.1%), and involved in medium-scale farming (47.2%). Furthermore, 50.8% of the farmers had primary or secondary education. Although farmers use different weed control methods, more than half of them (54.7%) use herbicides. Most farmers (92.6%) are engaged in the use of IWM, However, 73.5% of them use a combination of herbicides and hoe weeding. Although not properly practiced, farmers perceived IWM as having socio-environmental (29.229%) and techno-efficacious (23.495%) benefits over either hoe weeding or herbicides used alone. The findings suggest a need to train farmers on all aspects of IWM to achieve self-sufficiency in food production in Kwara State.

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Sensitivity of imidazolinone-resistant red rice (Oryza sativa L.) to glyphosate and glufosinate

Ciência Rural ◽

10.1590/0103-8478cr20140896 ◽

2015 ◽

Vol 45 (9) ◽

pp. 1557-1563 ◽

Cited By ~ 4

Author(s):

Guilherme Vestena Cassol ◽

Luis Antonio de Avila ◽

Carla Rejane Zemolin ◽

Andrey Piveta ◽

Dirceu Agostinetto ◽

...

Keyword(s):

Weed Management ◽

Management Practices ◽

Oryza Sativa L ◽

Dry Weight ◽

Integrated Weed Management ◽

Rio Grande Do Sul ◽

Red Rice ◽

Resistance Evolution ◽

Logistic Analysis ◽

Imidazolinone Herbicides

Dose-response experiments were carried out to evaluate the sensitivity of imidazolinone-resistant red rice to nonselective herbicides currently used in rice-soybean rotation in Rio Grande do Sul. Two red rice biotypes previously identified as resistant and susceptible to the imidazolinone herbicides were treated with imazapic plus imazapic, glyphosate and glufosinate under nine herbicide rates. A non-linear log-logistic analysis was used to estimate the herbicide rate that provided 50% red rice control and dry weight reduction (GR50). Imidazolinone-resistant red rice exhibited greater GR50 values than imidazolinone-susceptible biotype for imazapyr plus imazapic. In contrast, both imidazolinone-resistant and susceptible red rice showed similar GR50values for glyphosate and glufosinate. These results indicate that glyphosate and glufosinate effectively control imidazolinone-resistant red rice at similar herbicide rates used to control imidazolinone-susceptible; however, integrated weed management practices must be adopted in rice-soybean rotation to delay resistance evolution of red rice populations to glyphosate and glufosinate

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