When it comes to understanding how cotton producers are waging an all-out war on weed resistance this year, seeing is believing. That’s the impression I received after visiting the Memphis Agricenter International research farm recently to visit with the facility’s research director, Bruce Kirksey. I’ve seen many fields in the past few years that were overwhelmed by outbreaks of resistant pigweed. But it takes a closer view of the soil to appreciate the scope of this problem.
In our cover story on pages 10 and 11, Kirksey and Mississippi Extension cotton specialist Darrin Dodds discuss how tankmixing will play an important role in the fight against weed resistance.
After our conversation about the importance of effective tankmix partners, Bruce took me out to a field on the western side of the Agricenter. The field was cultivated and appeared ready for an early season residual herbicide application. As Bruce so aptly pointed out, cultivating the soil is another tool to use against weed resistance, but there is a pitfall involved in this practice. When the soil is disturbed, it can move seeds to the surface, creating a chance for a new pigweed outbreak.
At first, I had my doubts about this possibility. But, then, Bruce pointed to some very small weeds popping through the surface. If these small pigweed aren’t stopped, they will grow rapidly, produce seed, and a field could be taken over. If you turn to page 11, you can see this small pigweed popping up through the dirt. At first glance, it looks innocent enough. But this is how it all starts for any outbreak of resistant pigweed.
As reported in the story, a research farm’s challenges are different because there is a diverse mix of crops, and, as Kirksey points out, it’s hard to do an early burndown when it’s unclear what crops will be planted on any particular field. However, this is the kind of information that ultimately would be valuable for any farmer who has a crop mix on his acreage.
It reminds me of the first time I saw some serious resistant pigweed in a cotton field in south Georgia five or six years ago. A consultant took me out to the field in late July to see a worst-case scenario. The farmer had some pigweed outbreaks the previous year but didn’t think it was that serious. The next year, it didn’t look like a cotton farm. The weed population had quadrupled and had taken over the field. That’s when the chopping crews came in and tried to salvage the crop, but it was too late.
Moral of the story? Don’t underestimate pigweeds – even if they resemble a patch of clover in your front yard.
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