Based on last year’s scouting, 2022 is predicted to be another tough year for corn rootworm in areas of the Midwest. Make sure you’re staying vigilant!
With the price of corn looking desirable, farmers may be replanting corn this spring, explains entomologist PJ Liesch. He reminds farmers that back-to-back corn plantings increase rootworm risk. The best mitigation practice is crop rotation.
Liesch, also known as ‘the Wisconsin Bug Guy,’ directs the UW Insect Diagnostics Lab.
Corn rootworm can cause extensive damage to corn crops, he says. Larvae feed on roots in late spring and early summer, causing stalks to tip over. Adults feed on leaves and silks in the late summer, inhibiting pollination. The number of adults in your field in the fall is an indicator of the larvae to be there in the spring.
If you know you’ll have rootworm, try seed variations, Liesch suggests. He adds you should talk to your co-op about the strength of insecticides before applying, because rootworm is very adaptive to repetitive pest management. Pesticide resistance could be regional. Leisch says rootworm may be adaptive to an insecticide in Grant County, but not Kenosha County, for example.