There are four species of billbugs, but the bluegrass billbug is the most common in Kansas. Damage occurs early in the growing season, usually in lowlands near creeks. Adult billbugs destroy the growing point within the stalks of young plants near the soil surface. The larva is a white, robust, legless grub that tunnels in the lower stem and roots. Infested plants become twisted and distorted and will not yield. Damage is often associated with areas infested with yellow nutsedge, a preferred wild host plant.
Source of information
J.P. Michaud (http://entomology.k-state.edu/extension/insect-information/crop-pests/corn/billbug2.html)
Pest photo source
J.P. Michaud, KSU Entomology