10 LONG-TERM STRATEGIES
Resistant weeds are not a new problem. In fact, the first documented case stretches all the way back to 1970. In the years following, the problem has become outright staggering, with a total of 481 unique cases of resistance documented by the International Survey of Herbicide Resistant Weeds.
The problem may feel overwhelming, but farmers have a clear plan of attack when it comes to long-term planning against weed resistance. Following years of research and study, Bayer specialists recommend implementing as many of the following practices as possible for the best results:
- Rotate crops.
- Rotate herbicide-tolerant seed traits.
- Use multiple, effective modes of action.
- Scout regularly to keep current on what weed species require management.
- Apply pre-emergent herbicides to start the season with clean fields.
- Use residual herbicides when possible to keep fields clean.
- Apply herbicides correctly according to label instructions.
- Be diligent about controlling weed escapes.
- Adopt a zero-tolerance attitude of weeds in the soil bank.
- Clean equipment to avoid transferring resistant seeds into clean fields.
Remember: There’s no so-called “silver bullet,” so it can be helpful to think of every single herbicide or management practice as a piece of a larger puzzle.
According to Bryan Young, professor of plant pathology at Purdue University, there are several questions farmers should always ask when considering weed resistance.
First, what is the total weed spectrum, and what are the most aggressive species in a given field? Be aware that some species, including Palmer amaranth, water hemp, marestail and ragweed, are already resistant to multiple herbicide classes.
With that in mind, closely analyze the scope of weeds versus the solutions available. The ideal program will control targeted weeds, deliver multiple modes of action and provide residual activity throughout the season.