18. Resistance tip: Usemultiple modes of action. This kills any weed biotype beginning to resist a herbicide mode of action.
“I start clean with a timely burndown before planting,” says Haigwood. A residual herbicide permits him to plant soybeans prior to postemergence applications. On fields with glyphosate-resistant weeds, the postemergence application is a PPO-inhibitor herbicide.
Be cautious, though. Multiple modes may not work for preexisting resistance. For example, ALS herbicides will not control waterhemp in Iowa, given most populations already resist ALS herbicides, says Owen.
19. “In the South, we essentially have driven the (Roundup Ready) technology off the cliff,” says Ford Baldwin, co-owner of Practical Weed Consultants and retired University of Arkansas Extension weed scientist. “We did the same thing over and over until it didn't work anymore. It failed first on marestail and now it's failed on Palmer amaranth.
“It's to the point where farmers have gotten land taken away from them for weed issues,” he says. “Or landlords have trouble renting land to good farmers who want to take over clean fields and don't want to take over a mess.”