WHAT IS IT?
Boxelder bugs (Boisea trivittata) are not beetles, but true bugs. They belong to the family Rhopalidae of the order Hemiptera. Although this family of insects are referred to as ‘scentless plant bugs,’ they will release a bad tasting compound to thwart predators. They are black insects with distinctive bright red or orange markings, which makes them easily recognizable to most people. Adult boxelder bugs typically grow to be a half inch in length.
The boxelder bug gets its name from the species of tree with which it is most often associated: the boxelder tree (Acer negundo). This bug prefers female boxelder trees, but occasionally bothers various species of maple and ash trees.
While the boxelder bug does feed on the tree in which it resides, it has never been shown to cause significant damage to its host tree. The insect is primarily a pest because it often enters homes and other buildings. This can be a significant nuisance to people who live near an area where these bugs have congregated. However, they do not bite, sting, or transmit disease.
Boxelder bugs only have three distinct stages of development: eggs, nymphs (simply miniature versions of adults) and adults. During late summer and fall, boxelder bugs will leave the tree from which they have been feeding. This is when the bugs will typically invade a nearby home. Houses and buildings with more sun exposure tend to attract more insects because the bug prefers warmer environments. Some studies have also shown that the boxelder bug is more likely to invade homes or buildings that are taller than its surroundings. They will overwinter as adults, emerging from their hiding places to lay eggs in the spring.
Many insecticides offer little control of boxelder bugs, while a spray of dishwasher soap and water on the areas where they congregate (doorframes, siding, etc.) can be quite effective. Sealing off entryways into your home is also a great deterrent.