Weeds that won’t die is a nightmare for any farmer. An even more terrifying situation is if those weeds can’t be killed because they are resistant to herbicide.
"Herbicide resistance is not a new phenomenon," says Kevin Bradley, University of Missouri extension weed scientist. "We’ve been talking about it for decades."
And, as time passes, it is becoming a bigger problem.
Here are the glyphosate-resistant weeds in the U.S., as of 2010, courtesy of Bradley:
(click to enlarge)
"I add a few more dots every year," Bradley says. "The problem is it hasn’t gotten any better, in fact it has gotten worse."
Here are some best management practices for reducing weed resistance:
- Scout before herbicide application
- Scout after herbicide application
- Start with a clean field
- Control weeds early when small
- Control weed escapes to prevent seed
- Clean equipment before leaving field
- Using new commercial weed-free seed
- Using herbicides with different modes of action
- Using tillage to supplemental herbicides
- Using the labeled rate