Mean cumulative western corn rootworm (Diabrotica virgifera virgifera) adults per emergence cage. Error bars indicate ± standard error of the mean. Uppercase letters represent cornfields A–E. One-way analysis of variance from cumulative values on 26 September revealed significant field effects (F_{4, 35} = 20.63, P < 0.0001) on mean cumulative D. v. virgifera beetles per emergence cage (n = 8). Means with different lowercase letters are significantly different (P < 0.05).