The winter meeting season has given farmers a lot to think about and Dr. Bryan Young of Southern Illinois University is one of the people prompting thought. Recently Young and a couple of other academics helped plan a series of seminars sponsored by the Illinois Soybean Association to get farmers the latest information available. I attended the nearby seminar one of the events, the one where Young presented. This blog pulls together tweeting from the event and a video we shot with Young after the seminar was over.
Quite a bit of the day’s conversation was shared on Twitter, here are some of the highlights:
History of Weed Resistance
- The importance of delivering a high quality product can not be overstated as the global market is so competitive
- Farmers need to push for both high quality & high yield. That is what is needed in today’s market.
- There have been other products with herbicide resistance. Important to get the information out.
- He’s showing a dozen resistant weeds some have been resistant for 50 years or so with triazines, then ALS, etc
- In 2000, there was no glyphosate resistance in the Midwest. Now have marestail/horseweed which tillage can help manage, but now waterhemp & ragweed
- Flooding issues have facilitated resistance spread with resistant weed seeds floating from neighboring field to others
- Farmers sometimes miss there is a problem, thinking something else. Need to assume they have to do something now and work proactively, especially if they are dealing with waterhemp, marestail, Palmer amaranth and/or ragweed.
- Waterhemp has been resistant to various herbicides since the 1990s. Have resistance to herbicides in GMO & non-GMO beans
- Weed management challenges of the early 1990s were really tough. That was when ALS herbicides were an issue and ALS-resistant weeds continue to influence weed management today.
Managing Resistant Weeds Today
- Need to remember what you have in the field the year before, as it may help you look at pre-emerge products differently. Important to use them
- Will never find a mode of action more effective on weeds than glyphosate. Roundup is a great product even in light of resistance
- If you see any change in how effective a product is, you need to start looking at mixing up your program. Better to be changing program up anyway.
- Young started seeing problems with waterhemp in 2002. If it takes a second application, you may have already hurt your yields due to weed competition
- Need to be careful about reliance on a single mode of action without adding any other product.
- You cannot till or trait-rotate your way out of resistance once it occurs in a field. Need to know what is there & take appropriate action tailored to the situation.
- Preplant tillage by itself will not prevent herbicide resistance, Young says.
- Things to do? Rotate crops, use cover crops, apply soil applied residuals, consider physical controls, multiple modes of action, etc
- Young uses DIRT to fight Diversify (chemical, mechanical, cultural, etc) Integrate (2 effective modes) Rate (full rates, PRE or POST) Timing (apply at optimal times for both PRE and POST)
- Need to be getting control before breakthroughs or cleaning up when the are less than 4 inches
- Using a residual herbicide at planting to keep it taken care of.
- Young says give weeds the finger! Control weeds then they are no longer than your finger, 2-4 inches tall. View photo