Development of a gut content ELISA as a potential tracking method for variant western corn rootworm, Diabrotica virgifera virgifera

A crop rotation-resistant variant of the Western Corn Rootworm, Diabrotica virgifera virgifera Leconte, poses a management problem in rotated corn fields in parts of the Midwestern U.S. In order for growers to make more informed decisions regarding management of this pest, reliable methods for tracking its distribution are needed. WCR adults were collected from areas of historically high, moderate, and low levels of variant pressure using Pherocon® CRW lure traps. The level of soybean herbivory in these beetles can be used as a marker to estimate variant rootworm pressure. ELISA assays have been used in other systems to analyze insect gut contents to determine predator-prey relationships. We discuss development of an indirect ELISA assay designed to detect the presence of soybean foliage within the gut of adult rootworm females. Combined with numerical data on adult WCR abundance, this assay could provide growers with a useful, quantitative tool for estimating the risk of WCR infestation in first-year corn, lending confidence to management decisions.