Western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), is among the most serious pests of corn in the US Corn Belt. For the past two decades, genetically engineered corn that produces insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt) has played a key role in the management of this pest. Bt corn kills western corn rootworm larvae, and reduces larval feeding injury, which is the primary cause of yield loss. However, the rapid adoption of Bt corn by farmers has been met with an equally swift counter response, with populations of this pest evolving resistance to all currently available Bt traits. Key factors affecting rates of resistance development include non-recessive inheritance and minimal fitness costs of resistance, both of which heighten the risk of resistance evolution. The risk of resistance is further compounded by the limited dispersal displayed by adult western corn rootworm, which allows resistance to build within fields when the same transgenic traits are used for multiple seasons. New transgenic traits offer a means to continue the use of transgenic corn for management of western corn rootworm, but applying insights from past resistance issues will be of central importance for preserving the utility of these new technologies. In particular, applying a greater diversity of management approaches within fields will be essential for enhancing the sustainability of new transgenic traits.
