Resistant Weeds: Not a Question of If, but When
The daily challenges farmers face can be numerous: machinery repairs, pest pressures and, of course, the weather, just to name a few. But another, growing challenge has been added to that list for farmers in many regions of the country: herbicide-resistant weeds. And for those farmers who have yet to deal with resistance issues, “it’s not a question of if, but when,” warns Illinois farmer Nathan Hasheider.
Hasheider farms with Dean Campbell on Campbell’s farm in southern Illinois, near the town of Coulterville. They grow corn, soybeans and wheat, in addition to soybeans and wheat for seed.
Campbell and Hasheider noticed the resistance problem in their soybean fields first, starting about five years ago.
“The problem started slowly but has now become a more formidable challenge,” says Hasheider.
The first herbicide-resistant-weed culprits included marestail and waterhemp. “We’re on the lookout now for Palmer amaranth, which has been confirmed as a resistant weed in our area,” Hasheider says.
The resistant weeds have caused the pair to make a few changes to their weed-management program. For instance, they are also using more residual herbicides and applying herbicides earlier in the season to hit weeds earlier in their life cycle. Aggressive scouting during the growing season is necessary to stay ahead of the issue.
“In the past five years, we have put more focus on rotating herbicides with different modes of action and making an additional herbicide application in corn, soybeans, and double-crop soybeans.” Hasheider says.
These actions come with an increase in overall production costs, but Hasheider believes the extra investment is worth it to slow the weeds now. He estimates an increase of 7 to 8 percent for cornfields and 10 to 12 percent for soybean fields.
“The biggest payoff is managing for lower future production costs by acting on the resistance issue now,” says Hasheider.
And it doesn’t take a whole field of weeds for the resistance problem to grow.
“Each generation of a resistant waterhemp plant that goes through reproduction can add another 400,000 to 1 million seeds back into the soil that you will have to have to control sometime in the future,” says Hasheider. “If you see a herbicide-resistance issue in your fields, you need to address it now. Delaying action will only make the issue more difficult to solve in the future.”