By LEHIGH COUNTY EXTENSION

Boxelder bugs (Boisea trivittas) are considered a fall nuisance to those of us who have boxelder trees (Acer negundo) near our homes. As the temperatures start to drop, these insects decide that a good overwintering site is in our homes.

For homeowners unfamiliar with boxelder bugs, the adults are about 1/2-long, a brownish-black color, with overlapping wings that form an “X.” The adults have three orange or red stripes, two going down the outside of the body and one behind the head. Part of each wing is also edged in orange or red. In the nymph stage, the bugs are a bit more dramatic in coloration because they have bright red abdomens.

In spring as the weather starts to warm up and as boxelder buds are opening, adults emerge from their overwintering sites and fly to the boxelder trees. After mating, the female lays her small, red eggs in the bark’s cracks and crevices, and also on young leaves. In 10 - 14 days, the eggs hatch into bright red nymphs that feed on leaves and seeds. They insert their piercing-sucking mouth parts into the tissue and continue to feed until they reach adulthood. After reaching adulthood, they continue to feed on the leaves and seed until the weather starts to cool when the bugs start looking for a home to overwinter.

What makes our homes attractive is the type of sun exposure. A nice sunny southern or western exposure is ideal for the insects. They push into cracks, crevices and spaces, eventually winding up inside our homes, in our attics and between walls.

During winter, the boxelder bugs are mostly inactive. But if we experience any mild, sunny days, all bets are off. The increase in temperature lures them out of hibernation and they follow the warmth right into our living spaces. Once inside, they head for windows and any other sunny areas. Be careful not to crush them as a stain and-or odor may be left behind. Vacuum them up and discard in an outside trash can.

Some simple solutions to keep boxelder bugs, and stink bugs, from entering our homes are:

Repair damaged window or door screens.

Seal areas where cable and phone lines enter, around outdoor faucets, and dryer vents.

Install a rubber seal along the bottom of garage doors.

Contrary to popular belief, boxelder bugs do not reproduce in our homes, nor do they cause damage.

Growing Green” is contributed by Lehigh County Extension Office Staff and Master Gardeners. Information: Lehigh County Extension Office, 610-391-9840; Northampton County Extension Office, 610-746-1970.