Management of the western corn rootworm, Diabrotica virgifera virgifera LeConte, using transgenic bt maize

Abstract

The western corn rootworm, Diabrotica virgifera virgifera LeConte, is an important pest of maize, Zea mays L., in the United States and Europe. In the United States, transgenic maize hybrids that express Cry endotoxin proteins from the soil bacterium Bacillus thuringiensis Berliner (Bt) have been developed to limit feeding damage caused by corn rootworm larvae. Transgenic maize expressing the Cry3Bb1 protein was first registered for commercial sale in 2003, and two additional products expressing different proteins were registered for commercial sale in 2005 (Cry34/35Ab1) and 2006 (mCry3A). More recently a fourth Cry protein, eCry3.1Ab, was registered as a pyramid with mCry3A in 2013. Although the United States Environmental Protection Agency has mandated that all registrants of Bt crops submit an insect resistance management (IRM) plan prior to registration, the long-term viability of transgenic Bt maize for control of western corn rootworm remains uncertain. Under laboratory conditions, selected western corn rootworm populations have developed resistance to all commercially available Bt products as well as the eCry3.1Ab protein. In addition, field resistance to transgenic Bt maize has been documented in certain fields in the United States. To extend the lifetime of this management option for the future, additional improvements in resistance management plans will be needed.