Crop rotation is the key to Charles’ corn rootworm management strategy.

In much of the Corn Belt, rotation is still a simple but effective way to control corn rootworms, says Potter, the Minnesota entomologist. Even on heavily infested ground, taking the field out of corn for a year “eliminates western corn rootworms completely in that field. The following year, you should be able to plant non-Bt-RW corn without insecticide.”

However, there are some situations where a two-year rotation is not effective for controlling corn rootworms:

  • When volunteer corn in soybeans is not controlled, which allows corn rootworms to survive, defeating the purpose of rotation.
  • In Midwest regions where rootworms have adapted to corn-soybean rotations.

Northern corn rootworms, which developed extended diapause, have become less common, Potter says, so growers in the northern rootworms’ historic range can again use crop rotation to manage the pest.

We’ve moved away from an integrated pest management system to an insurance mindset now for managing many insects, especially corn rootworm, says Mike Gray, University of Illinois Extension entomologist.