They are found in large aggregations on the seeds of boxelder, and to a lesser extent maple and ash.
The major objection to these bugs is that they congregate in clusters on the outside walls, and then invade the home in fall and spring. Damage to host plant seed is minimal since damaged seeds are shed later in the season. The eggs are red and the bright red nymphs look like the adult without wings. The front wings and thorax are gray-black to black with thin bright red markings. The onset of the harsh winter weather causes all immature stages of boxelder bugs to die, while adults seek overwinter shelter, which may be your house.ĭuring overwintering time, boxelder bugs do not feed or reproduce.Pest description and damage The adult boxelder bug is a red, flat, and elongate bug about 0.5 inch long. This is when they become most noticeably visible to people. In the fall, boxelder bugs congregate on the trunk of female boxelder trees or on the ground level by the host plants, then they migrate to the sunny sides of buildings. New adult boxelder bugs mate and females lay eggs to start the second generation. This may take up to 60 days before they become adults by mid-summer. Newly hatched nymphs pass through five nymphal developmental instars. In spring, female boxelder bugs lay irregular masses of eggs on leaves, in cracks and crevices of the host tree bark, or on grasses and stones near the host plant.Įggs usually hatch in 11-19 days depending on temperature and relative humidity.
Once indoors, boxelder bugs can be seen hiding or clustering near light fixtures or around windows and vents.īoxelder boxes develop by gradual metamorphosis from egg to nymph, and then to adult. Therefore, boxelder bugs may enter homes through open windows or doors, especially at night when interior lights are on. On sunny and warm winter days, a few overwintering adult boxelder bugs may become active and can be seen around windows or warm places.īoxelder bugs are attracted to light. Thousands of boxelder bugs can congregate on a single structure, while neighboring buildings may have relatively few.Īdult boxelder bugs hibernate through the winter in cracks and crevices in and around buildings. Adult boxelder bugs typically can fly several blocks, although in some rare cases they will travel as far as two miles.īoxelder bugs are especially attracted to warm areas on buildings with a large southern or western exposure. The migration of the second generation to the sunny sides of buildings usually begins from mid-September to mid-October. Then they fly off to a convenient host to lay eggs and start their lifecycle.įrom mid-May to mid-July, adults and nymphs congregate on the low vegetation or ground near the female boxelder trees feeding on the fallen seeds produced the previous year.įrom mid-July to mid-September, boxelder bugs congregate on the trunk of female boxelder trees and ground. In the early spring, typically in late April to early May, boxelder bugs become noticeable to the eye again as they congregate on the sunlit sides (south/west) of the building.