What is in this article?:
- Top strategies to combat herbicide resistance
- Consider all available options
• WSSA scientists say the single most important factor contributing to resistance is overreliance on a single herbicide — or group of herbicides — with the same mechanism of action.
• Weeds most often develop resistance in response to such repeated and exclusive exposure, which renders the herbicide ineffective over time.
• The best management practices recommended by WSSA to combat herbicide resistance include common-sense, diversified approaches to weed management — from proactive steps to reduce the number of weed seeds in the soil to the use of well-established cultural practices to suppress weeds through crop competition.
Consider all available options
Recommendations from the Weed Science Society of America:
The Weed Science Society of America (WSSA) says that effective herbicide-resistance management programs must consider all available options for effective weed control and use the following best management practices (BMPs):
• Understand the biology of the weeds present.
• Use a diversified approach toward weed management focused on preventing weed seed production and reducing the number of weed seeds in the soil seed-bank.
• Plant into weed-free fields and then keep fields as weed free as possible.
• Plant weed-free crop seed.
• Scout fields routinely.
• Use multiple herbicide mechanisms of action that are effective against the most troublesome weeds or those most prone to herbicide resistance.
• Apply the labeled herbicide rate at recommended weed sizes.
• Emphasize cultural practices that suppress weeds by using crop competitiveness.
• Use mechanical and biological management practices where appropriate.
• Prevent field-to-field and within-field movement of weed seed or vegetative propagules.
• Manage weed seed at harvest and post-harvest to prevent a buildup of the weed seed-bank.
• Prevent an influx of weeds into the field by managing field borders.
In addition to recommending specific BMPs, the WSSA recommends/endorses the following:
• Reduce the weed seed-bank through diversified programs that minimize weed seed production.
• Implement a herbicide mechanism of action labeling system for all herbicide products, and conduct an awareness campaign.
• Communicate that discovery of new, effective herbicide mechanisms of action is rare and that the existing herbicide resource is exhaustible.
• Demonstrate the benefits and costs of proactive, diversified weed management systems for the mitigation of herbicide-resistant weeds.
• Foster the development of incentives by government agencies and industry that conserve critical herbicide mechanisms of action as a means to encourage adoption of best practices.
• Promote the application of full-labeled rates at the appropriate weed and crop growth stage. When tank mixtures are employed to control the range of weeds present in a field, each product should be used at the specified label rate appropriate for the weeds present.
• Identify and promote individual best management practices that fit specific farming segments with the greatest potential impact.
• Engage the public and private sectors in the promotion of best management practices, including those concerning appropriate herbicide use.
• Direct federal, state and industry funding to research addressing the substantial knowledge gaps in best management practices for herbicide resistance and to support cooperative extension services as vital agents in education for resistance management.
(Herbicide resistance has garnered tons of attention over the years, but perhaps nothing sums up the situation as well as Glyphosate-resistant pigweed in a class all alone among cotton pests).