Keep Black and Red Boxelder Bugs Out of Your Home

They Are a Nuisance You Needn't Tolerate

Boxelder Bug
boxelder bug. by Tom Murphy

Boxelder Bugs Are a Nuisance Pest

Boxelder bugs are primarily a nuisance pest because they do not bite, sting, infest food, or breed indoors. But large populations of these flying black bugs with red stripes can be very annoying, and their feces can stain surfaces such as walls, furniture, and drapes.

Boxelder bugs can sometimes be found in and around houseplants, in search of moisture, but they don't usually cause any damage to the plants.

Boxelder Bug Identification

In looks, boxelder bugs are:

  • About 1/2-inch long.
  • Black with three red stripes, vertical edge lines on its body and red lines on the edges of its wings.
  • When at rest, its wings lie flat on its back, with the red lines of the wings forming an upside-down V.

Habits and Biology of the Boxelder Bug

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, so people rarely notice them much in the trees.

But in the fall, when the boxelder bugs begin to take shelter in the structure of homes, the problems begins. The boxelder bugs will gather on the sun-warmed exterior walls, then squeeze into tiny cracks 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 into the warmth.

Once these 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 up the boxelder bugs.
  • Spray the bugs with a solution of two parts water to one part dish soap. This can kill the bugs when spraying directly on them.
  • Sweep up dead bugs with a broom, or vacuum.
  • Never squash a boxelder, as it can leave a stain.

Spring and Fall Boxelder Bug 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 any boxelder or silver maple trees near the home because these are a source of food and breeding.

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 won't always completely eliminate the boxelder bugs' entry, it can reduce entry points and numbers, and provide better control when combined with other techniques.
  • A two-part water/one-part dish soap solution can be sprayed on the exterior of the home to kill bugs that migrate to the walls in the fall. However, this has to be sprayed directly on the bugs, it does not have a residual effect for bugs landing on it. T
  • Call a pest management professional to spray a residual insecticide on the exterior walls of the home where the bugs are found. This will help prevent the bugs from landing for a while, but 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.