Problem Weed Control

Preserving New Technologies Requires Combining Several Systems To Control

MILAN, TENN.
   While some exciting technologies to combat resistant weeds are in the future, a mixture of the old standbys can make the difference between a good harvest and the loss of the whole cotton crop.
   Kelly Barnett, Ph.d. student in weed science at the University of Tennessee, recently recounted the efforts needed today to control problem weeds. She discussed the challenges that growers are facing now in cotton weed control.
   “We do have a lot of challenges but we also have options for managing weeds,” she said. “Glyphosate resistant weeds are our primary concern in the mid-south; glyphosate resistant pigweed in particular is our major concern, but we do have some options for growers to control that.
   “One of the things that we try to stress is applying a preemergence herbicide,” Barnett said. “We got away from that in the Roundup Ready era, but we’re getting back to that now. We have to put preemergence herbicides on every acre; we rely heavily on those to keep pigweed down. Then we need to come in with a timely post application, and for growers in Tennessee that is usually Liberty.”
   With the transition from the Roundup Ready era to a glufosinate-based or Libertybased system in cotton, farmers are relying heavily on Liberty. A timely post directed application, or hooded application in cotton, is certainly a tool farmers need to use as well.
   “We are making a lot of progress in Tennessee in cotton weed control and that’s great to see; but it takes a whole-system approach to control these weeds,” she added. “We can’t just rely on the chemistries. We do have some good options, and that means relying on other things as well, such as cover crops possibly. We are starting to see some of that come about, and, unfortunately, we are seeing a lot of chopping crews coming back to hoe pigweed. However, growers who are taking a zero tolerance approach and are really trying to eliminate pigweed from their fields are managing it well.”
   Barnett said some exciting technologies are expected in the future – 2,4-D resistant cotton, dicamba-resistant cotton, HPP-resistant cotton.
   “None of those are going to be a silver bullet like Roundup was, but they will be additional tools,” she said. “What we really have to stress is preserving the technologies we have now, preserving Liberty, which we are relying on heavily right now. For now, we are doing a good job managing that and hopefully we will continue to do that in the future. Δ
   BETTY VALLE GEGG-NAEGER: Senior Staff Writer, MidAmerica Farmer Grower  

Kelly Barnett, Ph.d. student in weed science at the University of Tennessee, discusses the challenges that growers are facing now in cotton weed control.