Boxelder beetles (also known as boxelder bugs) are a nuisance pest that swarms houses and other buildings in the fall. They are about ½ inch long and are dark grey to black and orange. As temperatures drop in the fall, they often crawl inside houses, where they can be annoying by staining carpets and other light-covered surfaces. Luckily they aren’t a threat to plants or humans.
Boxelder beetles feed on female box elder trees and occasionally on other trees such as maples and fruit trees. During the summer, all stages of their lifecycle can be found under the trees.

Since these insects smell bad when smashed, vacuuming them is one of the best ways to control them if they’re already inside the house. They can also be swept up or handpicked. Make sure that windows and doors are well-sealed so they can’t enter in the first place. Another control option is to remove any female box elder trees from your property.
If lots of the beetles are clustering outside of your home in early fall, you may also consider spraying them to keep them from coming in as the temperatures drop. Many products offer good control, such as those containing bifenthrin, lambda-cyhalothrin, and permethrin.