Pest ID: Boxelder Bug
Adults are about 1/2″ (11 – 14 mm) long; elongated oval, somewhat flattened with head narrower than pronotum. You can see by the Boxelder Bug picture that they are colored black with reddish lines on dorsum. Pronotum has reddish margins and median line. Basal half of wings have reddish margin. Moth-parts are piercing, sucking forming a beak held beneath the body when not in use. Antennae is 4 segmented, about half of the length of the body. Nymphs are similar to the adults but lack wings and are bright red in color.
Places Most Commonly Found:
The boxelder bug life-cycle starts when the overwintering adults emerge from hibernation and the females lay clusters of straw-yellow eggs on stones, leaves, grass, shrub, and trees, especially in the bark crevices of boxelder trees. These eggs turn red as the embryos develop and hatch in about 2 weeks. These nymphs feed on fallen boxelder seeds and later on new leaves, going though 5 instars. Adults become gregarious in the fall and congregate in large numbers on the south side or rocks, trees and buildings where the sun hits. They may fly in large masses to nearby buildings where they attempt to hibernate for the winter. The primary host plant is seed bearing (female) boxelder tree. However, they may occur in seed bearing Silver leaf maple trees.
Most Active Period:
Boxelder Bug infestation is most common and can become a problem in the spring when adults emerge from hibernation in wall voids and attempt to escape the building. They will accumulate near windows doors and other areas where sunlight penetrates the structure. In the fall they mass on the outside of structures and will enter through cracks, crevices and other entry points seeking wall voids and quiet, protected areas where they seek to hibernate.
Difficulty of Control:
The Boxelder Bug is difficult to control without using exclusion. Moderate to control if exclusion is combined with perimeter treatments and reduction of breeding areas.