Western Corn Rootworm Update

Western Corn Rootworm Update

Western corn rootworm field populations in eastern Iowa have developed resistance to the Cry3Bb1 rootworm trait according to Iowa State Entomologists. This is first confirmation of this type of resistance.

Researchers collected western corn rootworm adults from grower fields which had injury. They then grew the off-spring from these insects and conducted greenhouse research where the insects were exposed to the trait. The off-spring was less susceptible to this trait.

Growers were contacted and four problem fields had been planted to hybrids with this trait for at least three consecutive years. The control fields utilized a diversity of crops in a rotation and different management practices to prevent rootworm development and the insects did not develop resistance.

This is a reminder that we should continue planting the appropriate refuge and continuing to use integrated pest management practices such as pest scouting, use of economic thresholds, pest identification, crop rotation and other methods of pest control.

For more information, contact Wayne Flanary at 660-446-3724 or Heather Benedict at 660-425-6434, Regional Agronomists, University of Missouri Extension.