Identification of larvae of the wireworm complex (Coleoptera: Elateridae) collected from wheat and barley crops in Montana

Wireworms, the larval stage of click beetles (Coleoptera: Elateridae), are serious soil dwelling pests of small grains, corn, sugar beet and potato crops globally. About 9,300 species of click beetles in 400 different genera have been described worldwide. In North America 885 species in 60 genera have been identified. Larvae of less than 10% of the North American species are described, and of those, 95% are of a single larval instar. There is a potentially huge under estimation of the species diversity involved because the vast majority of species are identified only through adult male characters. The lack of identification keys for the larval stages is the greatest impediment to management of this species complex. In addition, different larval instars exhibit varying morphological characteristics, and generally only the last instar is described in those few species with a description. Very often wireworms occur in complexes of several species, and the efficacy of IPM tactics cannot be correctly evaluated without larval identification keys. The fact that not all insect species are equally susceptible to chemical, biological and cultural control tactics is well documented, therefore, toxicities of different insecticides may differ between wireworm species. We propose an interdisciplinary approach using morphological characteristics and molecular tools to identify the cryptic larval stages using identified adults as references. Our research will illustrate the wireworm species collected during the spring and summer 2010 in wheat, barley and lentil fields in four localities in Montana. Preliminary data demonstrating their identification based on COI gene sequences will also be presented.