Behavioral responses of western corn rootworm larvae (Coleoptera: Chrysomelidae) to roots of alternate hosts

Larvae of the western corn rootworm are able to survive on the roots of a number of alternate hosts, yet little is known about the chemical basis for larval host preferences.  In this study, larval host location behaviors were evaluated on roots and root extracts of both host and non-host grasses.  Chemical analysis of the roots was conducted in order to quantify compounds previously identified from corn roots and to correlate the chemistry of these plants with rootworm larval feeding, host recognition behavior and host status.  During the course of the experiments, a feeding deterrent effect was observed with oat root extracts and a toxic effect occurred when larvae were exposed to extracts of switchgrass roots.