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Box Elder Bug

Over Wintering True Bug

Biology: Many Hemipterous true bugs over winter as adults in shelters. In the PNW Region several species of little grey bugs of the Genera Irbisia and Ahryssa, etc.feed on grass land plants during the spring and early summer and overwinter in and around human structures. Locally known as “sage bugs” or “grey bugs” they seek layered places such as shingles, newspapers, firewood, folded fabric, etc. They are social and like to be together. Individual grass bugs emerge on warm, sunny, winter days to seek water droplets or house plants to obtain moisture. They do not feed while hibernating, but live off of their body fat.

Another pesty species is the Box Elder Bug, (Lepticorus trivittatus (Say), which a colorful larger bug than grass bugs. Box Elder Bugs are especially attracted to white houses and exhibit shelter seeking behavior much like the grass bugs. Rarely do the Stink Bugs (Genus Euchistus spp.) overwinter in homes, but prefer structures similar to the others including tree bark, wood piles, piles of lumber, etc.

All of these overwinter adult true bugs annoy humans by their presence even though they do not bite nor spread disease. Most true bugs stink! And they buzz around on active days. They congregate in sunny locations and try to go back outside when ready to mate and lay eggs in the spring.

Management: Many home owners and farmers want to spray these bugs as they come to hibernate in the fall of the year. They are easy to kill with products labeled for use in dwellings. However their little smelly bodies are still there! Our WSU suggestion? Vacuum them up in your home! Change vacuum bags because they stink after being filled with bugs.