Maize with behavioral resistance to western corn rootworm (Diabrotica virgifera virgifera) larvae

SUM 2162 is the first known example of a naturally-occurring maize (Zea mays L.) genotype with behavioral resistance to western corn rootworm (Diabrotica virgifera virgifera LeConte) larval feeding. Behavioral responses of neonate western corn rootworm 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 an isoline control. Chemical analysis showed that amounts of feeding stimulant compounds in roots of SUM2162 is not significantly different than amounts in the other genotypes or the isoline control. Subsequent tests suggest that roots of SUM2162 lack compounds that serve as initial contact cues for neonate western corn rootworm larvae. .