Host range of western spotted cucumber beetle (Coleoptera: Chrysomelidae) in California

The western spotted cucumber beetle, Diabrotica undecimpuntata undecimpunctata, is a serious pest of melons in the Sacramento Valley of California. Monitoring of alfalfa fields in the summers of 2008 and 2009 adjacent to melon fields in Yolo County revealed that alfalfa is a suitable host for both the larvae and the adults and a likely source of infestations in melons. To determine the host preference of the larval stage, a greenhouse experiment was conducted during the winter of 2009 examining several summer-time crops grown in the Sacramento Valley. Various measures of larval growth and development indicate that corn is the most preferred host. Change in head capsule width and survival percentage show that alfalfa and tomatoes are superior hosts to melons and that sunflower is an incompatible host.