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Box Elder Bugs

Box Elder Bugs

What are Box Elder Bugs?

In warm weather, box elder bugs live in maple, ash and box elder trees. The trees are host for the box elder bug since it eats the leaves, stays in the shade and lays eggs in the trees.

After a few days, the eggs hatch in the form of bright red nymphs. The box elder bug is black with red lines along the thorax and sides. Box elder bugs extract some liquid from host trees and rarely cause damage. Extremely large populations of box elder bugs can damage the host trees.

As the weather becomes cold, box elder bugs move toward the sunny sides of buildings and houses to overwinter. Cracks and crevices around the foundation, doors and windows provide protection from the elements. At times, the box elder bugs will find a way indoors.

Picture of box elder bug


The presence of box elder bugs is noticeable on warm days during the winter months whenever the building owner is outside. Although the box elder bug will not damage the structure, these insects can be a nuisance in large numbers. Inside, the box elder bug will fly toward the light that comes through windowpanes.


Damage to the building or house is not likely from an infestation of box elder bugs. Prevention is the best way to ensure that box elder bugs are not interested in overwintering in crevices. All cracks and crevices should be filled with caulk to eliminate places for the box elder bugs to hide.  Apply Scram Crawling Insect Killer where these insects may be harboring, traveling, breeding or entering the structure.

Maple, ash and box elder trees within close proximity of the structure can be removed if the problem is extreme. Few property owners like the thought of downing a tree because of a few bugs. Male box elder trees are preferable since the seeds of the female tree are a primary food source.