Boxelder Bug, Redshouldered Bug
Leptocoris (Boisea) trivittata, Jadera haematoloma
The boxelder bug is found mostly on female (seed-bearing) boxelder trees. The redshouldered bug prefers chinaberry and golden rain tree. Both are occasionally found on ash, maple, and some fruit trees.
These bugs do very little damage to their host plants even when they are present in large numbers. They are primarily nuisance pests when they begin to seek overwintering quarters in the late summer and fall. At this time they may be found in large numbers around homes, on shrubs and trees, and in lawns. They commonly attempt to enter homes and other buildings for protection. Problems may also occur on warm days during the winter and when they leave their overwintering quarters in the spring. They do not cause damage in the home by feeding but may stain fabrics or walls if they are crushed.
Adults of both species overwinter in protected places. They emerge in the spring when buds of their host trees open and fly back to their host plants, where they lay their eggs, usually in late April to early May. Both bugs prefer to feed on fruiting structures, including seeds that have matured and fallen to the ground, but will also feed on leaves. The first generation bugs mature and repeat the cycle. There are two generations per year.
Both species are grayish black bugs with red eyes and red markings and are about 1/2 inch long as adults. The boxelder bug has three red stripes behind the head, red lines on the outer edges of the wings, and a red margin on the back edge of the front half of the wings. The redshouldered bug has only two red stripes behind the head and has no red on the wings. Young bugs (nymphs) are smaller and do not have fully developed wings. They usually have more red markings than adults.
Please contact your local county extension office for current information.