The movement of adult western corn rootworms, Diabrotica virgifera virgifera, that have survived on transgenic corn plants is an important component of a resistance management program if a refuge is used to ensure susceptible beetles are maintained in the population. The objectives of this study were to evaluate the dispersal potential and egg laying capabilities of female western corn rootworms surviving as larvae on the roots or as adults exposed to leaves or silk of transgenic plants during the 2000 and 2001 field seasons. The transgenic plants evaluated that are being developed by Monsanto Co. for commercial release have genes inserted into them that code for the production of Bacillus thuringiensis (Cry3Bb) protein. Beetles were collected from emergence cages placed over transgenic and non-transgenic corn plants cut off at ground level. Additionally, beetles were collected in emergence cages from non-transgenic plants and caged in mesh bags over the silk or leaves of transgenic plants for 5 days. Female beetles from both experiments in both years were flown on a tethered flight mill for 24 hours. Beetles not flown were used to evaluate fecundity by allowing the females to mate with feral males and lay eggs in sifted soil. During the 2000 field season female beetles emerging from a transgenic event had significantly longer sustained flights (>20 minutes) than other treatments. Beetles caged on leaves of transgenic events had significantly higher mortality than beetles caged on leaves of controls. No differences in adult mortality were observed for beetles caged on silks of transgenic and non-transgenic plants. These experiments were repeated during the 2001 field season. Egg laying data for the 2000 season was still being collected at the writing of this abstract.
Species 1: Coleoptera Chrysomelidae Diabrotica virgifera virgifera (western corn rootworm)
Keywords: Cry3Bb, transgenic corn
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA