Four weeds in Indiana now have glyphosate resistance. Several also have resistance to one or more other chemical families of active ingredients. Sometimes the same weed may be resistant to more than one family of chemicals.
Steve Gauck, agronomist for Beck's Hybrids in southeast Indiana, says that help is on the way in the form of soybeans with new GMO-traits that will allow effective products that can help on resistant weeds to be sprayed postemergence over the soybeans. The problem is that federal regulators asked for more data a year ago, and have not said when any of these technologies might be approved.
The closest was thought to be Enlist from Dow AgroSciences. Originally, it was targeted for release in 2014. Now the date is 2015 with a question mark.
"We're talking about 2,4-D tolerant soybeans," Gauck says. "Some are worried about drift, but the product that Dow AgroSciences has developed for spraying over these beans is known as Colex-D. It's a formulation of 2,4-D that has very little drift or volatilization attributed to it."
In fact it's believed that Dow AgroSciences won't label regular 2,4-D amine or ester for application on these beans. Meanwhile, Monsanto is working on Roundup Ready Extend, which includes dicamba on dicamba-tolerant soybeans. Also in a holding pattern for approval, Gauck says Monsanto is working on formulations that will also not be as susceptible to drift as the original dicamba products.
Others in the wings, perhaps farther down the road, are Balance GT for Balance-tolerant soybeans and Callisto-tolerant soybeans from Syngenta.
The problem is what to do in the meantime, Gauck says. Many weed scientists are recommending going heavy on burndowns and including residual chemistry.
"The other option is Liberty on Liberty Link soybeans," he says. "The soybeans have been around for 20 years, and we have good genetics in Liberty Link lines. The herbicide works and there is no resistance to it at this time. It may take more management than just applying glyphosate."