Why Boxelder bugs become a problem in the fall

Boxelder bugs often become serious nuisance pests in the fall. The cooler nights provoke them to seek heat on the sides of buildings. The Sprague Pest Experts have seen an uptick in calls for Boxelder bugs across our entire service footprint, especially in Salt Lake City, Boise, and Eastern Oregon.

“Last year and this year, we’ve seen unprecedented numbers of Boxelder bugs because the winters have been so mild,” said Salt Lake City Branch Manager AJ Treleven. “The numbers are magnified because higher numbers of them have been able to survive the winter.”

Adult Boxelder bugs are about a half inch long, dark brown or black with conspicuous red markings. Immature boxelder bugs are smaller and a solid bright color.

As the nights get colder, they seek to warm up as quickly as possible on the sunny side of structures – this means that problems are typically most severe along the structure’s south and west sides. Our pest experts have seen them in such large numbers that the building looks like it’s crawling and moving.

“Boxelder bugs are occasional invaders,” Treleven explained, noting that the insects do not infest food or cause damage like pests do. “They are purely a cosmetic issue, but they are a big cosmetic issue – they are very noticeable and come in the thousands.”

To prevent the insect from entering your facility, seal openings in the early fall. Boxelder bugs move to shelter following frosts – it’s important to beat them to the punch. When sealing, pay special attention along the sun-exposed sides of your building.

Treleven and his team also apply spot treatments around the outside of windows and other entry cracks to further increase control. 

Struggling with unsightly Boxelder bugs on the side of your building? Sprague can help fix your commercial pest control problems in Denver, Boise, Seattle, Salt Lake City and throughout the Pacific Northwest and Intermountain regions.

Commercial Properties