You should also try to include sites of action with a relatively lower risk for developing resistant weeds, Storr says. For example, group 15 long chain fatty acid inhibitors have been on the market more than 40 years and have shown great resilience, Storr says. In the U.S., just one weed species has overcome it, making this chemistry a lower-risk choice for resistance management. Contrast that to Group 2 ALS inhibitors: in 30 years, 44 U.S. weed species have become immune to this class of chemicals.

Farmers are eagerly awaiting new herbicide-tolerant seed technologies, such as dicamba- or 2,4-D-tolerant soybeans, which will offer additional postemergence options. But if growers aren’t careful, Behnken warns, these new seed traits will soon face the same threats as Roundup Ready technology. “You will still need a plan for herbicide diversification, or we’ll develop resistance to these new tools, too.”