Resisting resistance TOP TEN

The battle against herbicide resistance begins in the field

The list of herbicide-resistant weeds grows each year. And some species are becoming real troublemakers, with resistance to more than one mode of action.

The Weed Science Society of America recently endorsed a series of best management practices designed to reduce the incidence of herbicide-resistant weeds. While the practices might not strike every grower as something new, we print them here as reminders to help curb herbicide resistance in general. According to the organization, the single most important factor contributing to resistance is over reliance on a single herbicide—or group of herbicides—with the same mechanism of action.

Along with the list BMPs came a word of warning from the weed scientists: new chemistry and effective herbicides don’t come along every day. Hoping that a silver bullet comes along is likely a failing strategy.

The Weed Science Society of America best management practices:
1. Understand the biology of the weeds present.
2. 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.
3. Plant into weed-free fields and then keep fields as weed free as possible.
4. Plant weed-free crop seed.
5. Scout fields routinely.
6. Use multiple herbicide mechanisms of action that are effective against the most troublesome weeds or those most prone to herbicide resistance.
7. Apply the labeled herbicide rate at recommended weed sizes.
8. Emphasize cultural practices that suppress weeds by using crop competitiveness.
9. Use mechanical and biological management practices where appropriate.
10. Prevent field-to-field and within-field movement of weed seed or vegetative propagules.
11. Manage weed seed at harvest and post-harvest to prevent a buildup of the weed seed-bank.
12. Prevent an influx of weeds into the field by managing field borders.