Weed Revolt Marches On | Glyphosate-Resistant Weed Population Grows Rapidly

Top 5 Strategies to Slow Resistant Weeds

Like most potential problems, it’s best to be pro-active rather than reactive to herbicide resistant weed threats, says Mike Owen, Iowa State University Extension weed specialist.

“The increase in the number of herbicide-resistant weeds is partly a function of the grower not believing it’s a problem until it’s already a train wreck,” he says. “By then, it’s too late.”

Rather than waiting for a train wreck to occur with resistant weeds overrunning your fields, Owen provides the following five strategies to head off a future crisis:

1. Admit there is a potential for disaster from herbicide overuse and take steps now to avert it.

2. Whatever you’ve done previously, don’t repeat again any time soon.

3. Use a pre-emergence residual herbicide to control early-emerging weeds.

4. Inclusion of some form of mechanical weed control is now absolutely necessary.

5. How you use postemergence and pre-emergence herbicides has to change. “In other words, don’t use a single mode of action (MOA) as your only weed control tool,” he says. “Don’t repeat the same herbicide MOA when applying a follow-up application.”

Although rotating the herbicide MOA is a good strategy, “rotation of the MOA will only delay the inevitable,” says Owen. “Every year you rotate a MOA, you get one more year’s use from it.”

Rotating MOA is just one strategy that helps, not the ultimate solution, he adds. “You don’t want to use any one tactic exclusively in a crop,” says Owen. “Instead, you need a diversity of tactics in every crop.”