Boxelder Bugs

- Boxelder bugs can cause more aggravation than almost any other pest! -

Summary: Boxelder bugs invade homes in the fall seeking shelter for the winter. They cause no damage but bugs that get into wall voids and attics may eventually enter into the living space. The key to combating this invasion is to prevent access to overwintering sites in the fall.

Jack DeAngelis, PhD

OSU Ext. Entomologist (ret.)

Identify boxelder bugs

Boxelder bugs, sometimes called maple bugs, are medium size insects about 1/2" long, dark grey with red markings on their back (see photo right). These otherwise harmless insects can become an extreme nuisance because of their tendency to congregate in large numbers on houses in the fall. If the congregating bugs gain entry to walls or attics they can become a problem all winter as they find their way into living spaces.

Boxelder bug life history

There is only one generation of these insects per year. Eggs are laid on maple leaves (the tree called boxelder, or box elder, is a type of maple tree) in early summer and young boxelder bugs develop there throughout the summer, without harming the trees. Young bugs resemble adults except they are more red in color and lack wings.

Boxelder bug (about 1/2 inch long). Note the red markings around the dark grey wings. Common misspellings and misnomers: boxelder beetles, box elder bugs (beetles), stink bugs.

In the fall adult bugs leave the maple trees in search of protected places to spend winter months. Large numbers may congregate on trees, and nearby houses, and cause a great deal of concern from affected homeowners. In spring the adults fly off to find maple trees on which to lay eggs to begin the cycle all over again. Eggs are not laid on houses, inside or out (see Life History of Boxelder Bugs) but only on host trees.

Boxelder bug control on houses

The best way to prevent problems with boxelder bugs is to discourage aggregation in the fall and control bugs that manage to find ways into exterior walls and attics. Homeowners can do these treatments themselves with low toxicity botanical insecticides and dusts (see How to Manage Boxelder Bug Infestations Around Your Home).

Boxelder Bug Control

Caulk around doors and windows, seal cracks.

Fall: Spray bugs landing on house with insecticidal soap, or other insecticides.

Apply insecticidal dusts to attic and exterior wall voids, if you have access to these spaces.

Fall-Winter: Vacuum up bugs found indoors, empty vacuum bag/canister.

Soaps, dusts and other supplies for boxelder bug control are available here (DoMyOwn.com).

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