A Nuisance Pest
Boxelder bugs are primarily a nuisance pest as they do not bite, sting, infest food, or cause property damage. Additionally, boxelder bugs do not breed indoor. However, excessive numbers can be very intrusive and annoying, and when populations are large, their excrement can stain surfaces such as walls, furniture, and drapes.
They can sometimes be found in and around houseplants, in search of moisture, but rarely will they cause any damage to the plants.
Boxelder bugs are:
- about 1/2-inch long.
- black with three red stripes and vertical edge lines on its thorax, and red lines on the edges of its wings.
- when at rest, its wings lie flat along its back, with the red lines of the wings forming an upside-down V.
Habits and Biology
During the warm days of spring and summer, boxelder bugs live and breed in boxelder and silver maple trees. Although they feed on the leaves, flowers and seed pods of the trees, they do not cause damage, thus people rarely take much notice of them during these seasons.
It is in the fall when the boxelder bugs begin to take shelter in structures that the problem begins. The boxelders will gather on the sun-warmed exteriors of buildings; then when the weather cools further, they will squeeze into and through tiny cracks and crevices in the home's structure, beneath siding, and under eaves. They will overwinter there until the warmth brings them out.
Unfortunately, the warmth that attracts them and brings the bugs out of hiding can be the heated air from inside your home. And because, like bugs such as stink bugs and squash bugs, boxelders can detect temperature differences of as little as one degree, it doesn't take much for them to decide it's time to move further into a warmed environment.
Further misfortune is that once the pests get into your home or office, there is little that can be done to eliminate them-except physical removal:
- Use a vacuum with a long-hose attachment to gather in the bugs.
- Spray the bugs with a solution of two parts water to one part dish soap. This can kill the bugs when spray directly on them.
- Sweep up dead bugs with a broom, or vacuum.
- Never squash a boxelder, as this can stain the surface on which it is killed.
Spring and Fall Control
Control is most effective in the spring or fall when the boxelder bugs are just beginning to emerge (spring) or shelter (fall).
The most permanent control of boxelder bugs is the removal of boxelder and silver maple trees near the home, as these are a source of food and place of breeding for the bugs when they are active during spring and summer.
However, if you prefer to not cut down trees, there are other options:
- Screen or caulk all cracks, crevices, gaps, and openings in your home's structure.
- Repair any torn or broken door or window screens, and ensure doors and windows are well-sealed.
- Although exclusion techniques are not proven to eliminate the bugs' entry in and of themselves, this can reduce potential entry points and numbers and provide better control when combined with other techniques.
- Similar to the in-home use of a soapy solution, this same two-part water/one-part dish soap solution can be sprayed on the exterior of the home to kill the bugs that migrate to the walls in the fall. This will not, however, have a residual effect, but would need to be reapplied every time the bugs congregate.
- Contract with a pest management professional to spray a residual insecticide on the exterior walls of the home where the bugs are found. Although the residual will help to deter the bugs from landing, it will not remain effective once cold weather sets in.
- A professional can also use a power sprayer on the trees to kill the nymphs before they can grow into adults and move into your home.