Western corn rootworm (Diabrotica virgifera virgifera) is a major pest of corn in the US. Larval density-dependent mortality can confound mortality estimates of Bt traits and soil-applied insecticides used to manage this pest. Although little work has been done to study density-dependent mortality of western corn rootworm larvae when feeding on Bt corn, there are some reports that suggest it does occur. Previous studies have shown the importance of including density-dependent mortality when developing insect resistance management plans. This study evaluated the effect of larval density-dependent mortality of western corn rootworm in Bt and non-Bt corn using artificial infestation at six egg densities ranging from 25 to 800 eggs per 30 cm of row. Logistic regression was used to test the effect of density of viable eggs on proportion survival to adulthood on Bt and non-Bt corn. Multiple linear regression was used to test if adult emergence and root injury could be used to estimate initial egg density. Understanding these interactions will increase our knowledge of interactions between western corn rootworm and corn, and aid in the development of approaches for insect resistance management.
