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.