Ecology of wireworms (Coleoptera:Elateridae) in cereal crops

Soil-dwelling insect pests pose special problems in many agro-ecosystems. They often have cryptic life cycles, making sampling difficult and damage hard to anticipate. Their management is therefore often based on preventative insecticides applied at planting or cultural practices. Wireworms, the subterranean larvae of click beetles have re-emerged as problematic pests on a wide variety of field crops in North America and globally. Wireworms feed on underground plant structures causing wilt, stunting, and even death to juvenile plants. With significantly high numbers the yields of entire fields can be lost. Major crops affected in the Pacific Northwest include potatoes, legumes, and cereals. Until recently, wireworms were effectively managed with broad spectrum insecticides, but the de-regulation of several of these pesticides has led to their re-emergence as major pests. Unfortunately, this “low pest status” resulted in little research on their biology and ecology, and thus farmers lack the fundamental knowledge to develop new management strategies. Here, I will present results from the first large-scale field survey of wireworm species in cereal fields of the Pacific Northwest. The survey revealed thirteen wireworm species found, although three species accounted vast majority of individuals collected. Distributions of all of these species, as well as their associations with climatic factors will be presented. Furthermore, I have explored how wireworm presence influences interactions with other wheat pests. Research showed that wireworm feeding causes induced defensive responses in plants protecting them from aphids. This suggests that wireworms may directly or indirectly impact entire communities in wheat cropping systems.