Maize with antixenosis (nonpreference) resistance to western corn rootworm larvae

SUM 2162 is the first known example of a naturally-occurring maize (Zea mays L.) genotype with antixenosis (nonpreference) resistance to western corn rootworm larval feeding. Behavioral responses of neonate western corn rootworm (Diabrotica virgifera virgifera LeConte) larvae were evaluated in laboratory bioassays with seven maize genotypes selected for native resistance to rootworm feeding damage. In soil bioassays with cut roots, no larvae entered the roots of the resistant variety SUM2162, but at least 75% of the larvae entered the roots of every other maize type. Larvae made significantly (P < 0.05) fewer feeding holes in the roots of SUM2162 than in all the other maize genotypes, except the isoline control. Chemical analysis of the roots showed that feeding stimulants did not account for the antixenosis. Subsequent tests suggest that roots of SUM2162 lack compounds that elicit host recognition behavior by neonate western corn rootworm larvae.