A Look at Proactive Prevention
Three principles of effective herbicide resistance management
How can you prevent herbicide-resistant weeds in your fields?
Adopt an integrated weed management (IWM) program that attacks weeds on many fronts and avoids overuse of any single chemistry. IWM employs a variety of cultural, chemical, mechanical and biological tactics, including:
- crop rotation
- cover crops
- hand-pulling weeds
- managing weeds on non-cropped areas
- cleaning equipment to avoid spreading seeds
Keep the following three principles of proactive resistance prevention in mind as you plan your weed control program:
- Know your weeds. The ancient Chinese saying “know your enemy” applies to weeds today. Knowing your weeds means identifying the main species in each field and understanding their biology so you can exploit their weaknesses. When do they emerge? How fast do they grow? How many seeds do they produce, and how long are the seeds viable in the soil? This knowledge is essential for choosing the correct herbicides, application timings and other effective control measures.
- Diversify herbicide use. Using the same herbicide or mode of action in the same field year after year leads to the evolution of herbicide-resistant weeds. To lower your risk of resistance, use multiple, effective herbicide sites of action every time you spray.
- Apply tank mixtures of herbicides that use different modes of action to kill target weeds. This limits the opportunities for weeds to develop resistance to any of the tank-mix partners.
- Include soil-applied, pre-emergence residual herbicides to extend weed control and improve postemergence control.
- Rotate herbicide modes of action within a season as well as between seasons.
- Rotate crops. Crop rotation cuts the risk of developing resistant weeds by allowing the use of different herbicides and modes of action, different planting and harvesting dates and different production practices.
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