Rootworn and other insects are making an early appearance across the Corn Belt. Ashley Dean, Extension specialist for field crop entomology at Iowa State University attributes the high numbers to the milder-than-usual temperatures that allowed the pest to overwinter.

Corn rootworm is widespread and is the top corn pest in Iowa. Loss yields can be up to 50% and nearly every Iowa cornfield is at some level of risk.

A recent report from shows moderate risks now in southeastern Kansas, Missouri, central/southern Indiana and western/central Ohio. Hatches are likely to be scattered due to recent heavy rainfall.

Bayer CropScience conducted corn rootworm beetle counts in 904 fields across 12 states last year. It discovered rootworm populations have expanded in some areas including northern Illinois, Wisconsin and Ontario. In addition, the BayerCropScience count found:

  • 53% of the corn fields had counts exceeding two bettles/trap/day
  • 71% of continuous corn fields sampled were above the economic threshold
  • 14% of first-year corn fields were above the economic threshold.

Read more on the 2024 rootworm outlook here.