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Fight weed resistance with overlapping residuals

Many of you may know that I grew up in eastern Colorado. It was a small farming town called Eads. I never dreamed I would live anywhere else. That area of the country is quite opposite, in terms of weather, from Missouri. In Eads, we always seemed to be in a drought (at least that’s what I remember). Here, we go from one extreme to another. I mention this because I’ve had the great opportunity to live in many places and have seen our agriculture community reach out to those in need. These past few months have once again proven why I love our agriculture community. People came together to help those affected by flood damage. They show up in times of trouble and don’t expect anything in return. I appreciate ev­eryone who has graciously donated goods and time to help those in need.

While we’ve had a trying spring, it’s time to focus on this growing season. We’ve talked about selecting the right nitrogen source and rate. We’ve talked about selecting the right adjuvant. Now, let’s talk about weed control.

Weed control is the hot topic at a lot of coffee shops. New traits will allow HPPD, dicamba and 2,4-D herbicides to be applied to soybeans. WOW. I bet we can treat them like the old Roundup Ready soybeans. WRONG. While that practice might work for a while, it’s not a good long-term plan.

Overlapping residuals is some­thing that we’ve discussed before. With the rapid adoption of the LibertyLink weed control system over the past couple of years, we have seen a decrease in the number of acres that are receiving overlap­ping residuals. On the other hand, in the Roundup Ready 2 Xtend system, we’ve seen the continued use of overlapping residuals. As we look to the future of the trait platform, most have tolerance to glufosinate. It’s even more important that we stew­ard these new technologies. We have been putting considerable selection pressure on the LibertyLink crops, and we need this system for future use. This should be an indication that we need to protect this trait.

You may have heard in the ag news that University of Illinois researchers identified a population of waterhemp in Illinois that is resistant to group 15 herbicides (Dual, Out­look, Zidua, Warrant). This class of herbicides has been doing the heavy lifting for many years. Waterhemp populations that are resistant to mul­tiple modes of action are becoming more common every year.

You may have also heard that a couple of companies have a new mode of action (MOA) in the pipe­line. This would be the first new MOA in several years. This is very exciting for a weed scientist. It will still be several years before we will see the new products placed with trial cooperators and even a few years after that before they are avail­able on the market, but it is exciting nonetheless.

In the near term, however, there is nothing new on the horizon. That’s all the more reason for us to focus on stewarding all of the technologies that we currently have. We must use good application methods to make sure we don’t run out of options.

As for the 2019 growing season, MFA will continue with our same protocol as last year when it comes to application of dicamba products XtendiMax, Engenia or FeXapan. MFA staff will evaluate sentinel plots weekly to determine soybean growth stages and potential cutoff dates for spraying dicamba in our different regions. Every Tuesday morning throughout the growing season, we will send out reports to all MFA employees and publish an updated map on our website to give a general outline of the soybean stages in the different regions. The map and other information will be available at

If you have any questions, please feel free to reach out to me or one of our MFA Agri Services, AGChoice or affiliate locations.

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