If this hypothesis is proven true, corn production throughout the Corn Belt could be affected significantly. Why this egg laying in soybean fields is occurring is not known at this time. Rapid dispersal of the western corn rootworm has occurred previously. As irrigation increased, western corn rootworms began to lay eggs in irrigated soils, many of which were treated with chlorinated hydrocarbon insecticides. Corn producers in neighboring states are watching with apprehension as the situation in Illinois unfolds.
Research is under way to keep crop rotation a viable option for corn rootworm management.
Western corn rootworm beetle feeding on soybean flowers. The use of crop rotation has, and continues to be, the main pest management strategy for corn rootworms in Illinois and across the Corn Belt. Only very isolated cases of first-year corn larval injury have been reported outside this cluster of counties. In addition to east-central Illinois, some producers in northwestern Indiana have reported similar rootworm problems in corn following soybeans. Thus far, no other states have indicated that they are experiencing western corn rootworm larval injury in first-year cornfields, suggesting the problem is very isolated.