When box elder bugs build up to large populations and invade a home they are usually pests only by their presence, although their piercing-sucking mouthparts can sometimes puncture skin, causing slight irritation. Box elder bugs do very little damage to the trees they attack, but at certain times of the year they can become a nuisance.
Adult box elder bugs will enter structures in the fall, seeking winter shelter. They seek shelter in protected places such as houses and other buildings, cracks or crevices in walls, doors, under windows and around foundations, particularly on south and west exposures. Box elder bugs can come out even during the dead of winter when it is cold outside and the sun is shining. They will then emerge in the spring to seek out host trees on which to feed and lay eggs.
