In Kansas, the western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), is one of the most economically important pests of corn. Crop losses and control costs attributed to Diabrotica spp. reach $1 billion annually in the U.S. Recently, Bt corn hybrids resistant to western corn rootworm larval damage have been field-tested for rootworm control. This study evaluated the effect of a specific Bt corn (YieldGard Rootworm®) for corn rootworm control on larval survival. Elytra length, fecundity, percent egg hatch, and longevity of adult D. v. virgifera that survived exposure to Bt corn in the larval stage were also evaluated. Two groups of D. v. virgifera adults were assessed. One group had emerged from Bt and non-Bt corn roots; the other group was obtained from a colony with no larval exposure to Bt corn and fed Bt or non-Bt corn silk and ears. Bt corn significantly reduced the number of D. v. virgifera beetles emerging from corn roots. In general, Bt corn had no significant effect on longevity, elytra length, and female fecundity of D. v. virgifera beetles emerging from Bt corn plants. Bt corn had no significant effect on longevity and female fecundity of D. v. virgifera beetles feeding only as adults on Bt corn silk and ears. In general, Bt corn had no effect on number of D. v. virgifera beetles feeding in the field on corn silk and on silk damage caused by adults. Generally, the results of this study demonstrated that Bt corn (MON 863) expressing the Cry3Bb1 toxin was extremely effective in reducing damage caused by D. v. virgifera larvae and had no significant effects on the longevity of beetles emerging from YieldGard Rootworm® corn.
Journal of the Kansas Entomological Society
Vol. 78 • No. 2
Vol. 78 • No. 2