Corn producers have an impressive array of materials for controlling weeds today, but the only way they can insure these products for future use is through careful management, says Dewey Lee, University of Georgia Extension agronomist.
“There's a way to maintain glyphosate and other effective products for years to come,” says Lee. “It's important that you manage your production systems to be able to use these chemistries effectively and to continue using them.”
Over the last several years, he says, there has been a rapid increase in the use of Roundup resistant commodities. According to USDA, 19 percent of the U.S. corn crop was treated with Roundup, and that's expected to increase this year.
“Sixty-nine percent of our cotton was treated in some form or fashion with glyphosate this past year, and 98 percent of our soybean crop was treated with Roundup. That is a concern,” says Lee.
A few weed species throughout the world have demonstrated some resistance to glyphosate, he says. In the United States, there have been reports of resistant horseweed and common ragweed, he adds.
“It's all around us,” says Lee. “We want to preserve the value of the chemistries available to us in corn. We need to look at tank-mixes. Make sure you take control of your weed spectrum and populations of some of the more difficult-to-control weeds.”
In a burndown environment, growers can tank-mix 2,4-D and do a very effective job of preserving a product such as glyphosate, he says.
“Or, you can alternate glyphosate with other herbicide mode-of-actions such as Accent, Option or Prowl. Keep these materials mixed on your farm, and you'll preserve the value of some of these broad-spectrum herbicides. If you're in a conventional production system, cold steel always is good,” says Lee.