Surveys taken in Washington, Oregon, and Idaho in 2013 to 2014 found that the species of wireworms present, and their abundance, vary greatly across the regions. Determining which species are present through proper scouting techniques is important for management, because different species vary in their biology, ecology, insecticide susceptibility, and crop impact (Horton 2006). Correct and timely identification prior to spring planting can provide an excellent return on investment.
Distribution of Wireworms in Pacific Northwest Cereal Cropping Systems
In 2013 and 2014, Milosavljevic, Esser, and Crowder conducted a large-scale survey across 20 counties in the inland Pacific Northwest (PNW) to examine the distribution of wireworms in spring and winter wheat fields and in conservation reserve program (CRP) land. Wireworms were present in samples from 87 percent of surveyed fields, and 14 different wireworm species were identified.
Identifying Wireworm Pest Species
Wireworms have slender and cylindrical segmented bodies consisting of a head, thorax with three pairs of legs, and a nine-segmented abdomen (Figure 4a; Berry 1998). The three most dominant species found in the inland PNW can be distinguished from each other based on variations in these body features (Lanchester 1946; Glen et al. 1943). A hand lens or microscope are useful tools for identifying the body structures to determine which species are present in a given field.
Western field wireworms are approximately 0.3 to 0.7 inches long, and yellowish-brown or orange in color (Figure 4b).