Examining potential differences between rotation-resistant and rotation-susceptible populations of the western corn rootworm

The western corn rootworm, Diabrotica virgifera virgifera LeConte, is a significant insect pest of corn, Zea mays L. Larvae of this pest feed on root tissue and cause corn plants to be susceptible to lodging. Costs of control and yield losses are estimated to approach $1 billion annually in the United States. The failure of crop rotation to adequately manage western corn rootworms was first reported in the mid-1990s in east-central Illinois and northern Indiana. Since that time, the rotation-resistance trait has spread throughout much of the central Corn Belt. A field experiment was designed to examine potential differences between rotation-resistant and rotation-susceptible populations of western corn rootworms. Some potential differences that are being explored are patterns of emergence, relative fitness, and the ability to injure transgenic Bt corn. Data from the second year of this multi-state, multi-year experiment will be discussed.