- Scout fields before and soon after herbicide applications – Correctly identify weeds and use whatever means are necessary to kill weeds that escape or germinate after chemical application.
- Diversify crop sequences – Crops with different lifecycles, such as winter annuals, perennial crops and summer annual crops, offer different planting and harvest times, more herbicide options and decreased risk of herbicide-resistant weeds.
- Consider weed biology and ecology – Consider tillage, crop sequence, soil fertility, planting date, crop competition, weed-seed longevity and herbicide response as you build your weed-management plan.
- Use effective pre-emergence herbicides – Apply effective pre-emergence herbicides at full rates and include multiple modes of action. Pre herbicides reduce weed emergence and allow flexibility in timing of post herbicide applications.
- Use effective post-emergence herbicides – Apply herbicides that include multiple modes of action in tank-mixes or in sequential applications.
- Use full herbicide rates – Full rates kill weeds and dead plants cannot produce resistant progeny. Reducedrates allow plants with low-level resistance to survive and produce offspring with higher levels of resistance.
- Spray weeds when they’re small – Small weeds, those less than 3 inches tall, are generally more susceptible to herbicides than large weeds.
- Practice zero tolerance – Scout fields after row closure and kill uncontrolled weeds, including by pulling them manually, if necessary. Seed from escaped weeds will contribute to the weed seedbank.
- Control weeds in field perimeters and non-crop areas – Weeds surviving a partial herbicide dose on field borders can be a repository for the introduction of resistant weeds into a field. Control weeds in all areas of the field where crops are not growing, including field edges, fence lines and waterways.
- Rotate herbicides with different modes of action – Diverse crop rotations can introduce herbicides with different modes of action to delay herbicide resistance.
- Use good sanitation – Clean tillage and harvest equipment to ensure weed seed will not be transported between fields.
- Evaluate – Review your weed-management results at the end of each season and revise to improve weed control next year.
These practices that can help, but fighting herbicide resistance starts with farmers knowing what they are up against.
“If you don’t know the enemy, how can you prepare to fight them,” asks Van Larson, a crop consultant based in Rochester, Minnesota.
Weed species respond differently to herbicides and tillage practices, so scouting and understanding which weeds are present sets the stage for farmers to develop a plan for eradicating the problem.
Weed control by season, that's the only way I can control these resistant weeds I have today.
I missed the fall season and it looks like winter too, so it's all put on spring this year. I hope we have enough time left to get decent weed control this year.
I hate weeds!