Iowa farmers are looking for solutions as they find certain weeds, especially waterhemp, are becoming harder to control. And, with Palmer amaranth — a particularly tough and damaging weed — creeping into the state, those concerns are higher than ever.
"We know (herbicide) resistance is an issue," says Joel DeJong, an Iowa State University (ISU) Extension field agronomist in northwest Iowa. "That’s why there is some renewed interest in how we’re managing weeds."
"Nature is very good about saying you’ve left a void in your management program, and we’re going to fill it. It’s always happened. It’s something we need to be resilient about."
Dustin Sage, a Black Hawk County farmer, noticed some weed escapes in his soybean fields in late June even after applying pre-emergence herbicides with residual control and a post-emergence tank mix with a couple of different modes of action.
"The waterhemp just didn’t die," he says. "I went out about a week after I sprayed it, and it was already regrowing. Once they’re up, I couldn’t get them killed any...