An entomologist may find the red edging of its black wings to be rather pretty, but when boxelder bugs invade your home, they can become quite a nuisance! Although this red and black bug does not cause damage, few people enjoy having large insects crawling out of cracks, onto their walls, windows, lights, or furniture.
If you have ever had boxelder bugs invade your home, you've probably sought information on their identification and control.
This article address some of the most commonly asked questions about this bug and its control.
1. How do I know if that bug on my wall is a boxelder bug?
At about 1/2-inh long, boxelder bugs (Boisea trivittata) are black with three red stripes, vertical edge lines on their bodies, and red lines on the edges of its wings. These markings make it appear as though its wings form an upside-down V when they are resting with their wings lying flat (See photo at left.)
2. Why are these large bugs coming into my home?
As their name implies, boxelder bugs are attracted to boxelder trees. If you have these, or silver maple trees to which they are also attracted, around your home or neighborhood, you are very likely to have boxelder bugs. In the fall, as they begin to seek shelter for the upcoming cold months of winter, they are attracted to the warm, sunny sides of homes. From there they slip between cracks and gaps in the siding, around doors and windows, etc., often ending up inside the home during the winter.
3. What happens if I don't get rid of them?
The boxelders will overwinter in the walls of the home until the warmth brings them out. And that warmth can be the heated air from inside your home, bringing them out of the walls into the rooms of your home during the winter months. Like bugs such as stink bugs and squash bugs, boxelders can detect temperature differences of as little as one degree, so it doesn't take much for them to decide it's time to move further into a warmed environment.
4. Will the bugs bite or me or my family?
No, boxelders bugs do not bite or sting people
5. I've seen some on my trees and plants. Will the bugs hurt the foliage?
Although they live and breed in boxelder and silver maple trees and feed on the leaves, flowers and seed pods, they do not cause damage. Boxelder bugs in and around houseplants are generally in search of moisture. Rarely will they cause any damage to these plants either.
6. Do boxelder bugs cause any other damage?
Not unless there are high populations. Boxelder bugs are primarily a nuisance pest. They only live for a few days and do not infest food or cause property damage, and they do not do not breed indoors. But when a lot of them get into your home, they can be very intrusive and annoying, and their excrement can stain surfaces such as walls, furniture, and drapes.
7. How do I get rid of boxelder bugs that get into my home?
Once the pests get in, physical removal is best, and really is the only practical way to get rid of them. A few options are:
- Use a vacuum with a long hose attachment to gather up the bugs.
- Directly spray the bugs with a dish soap/water solution (See question #10 below). Then ...
- Sweep up dead bugs with a broom, or vacuum.
Never squash a boxelder bug; this can stain the surface on which it is killed.
8. How can I keep the bugs off my home in the first place?
A residual insecticide can be sprayed on the exterior walls of the home where the bugs are found. This is most effective in the spring or fall when the boxelder bugs are just beginning to emerge (spring) or shelter (fall). The residual will help to deter the bugs from landing, it will not remain effective once cold weather sets in. For do-it-yourselfers, there are retail products labeled for boxelder bug control. Be sure to purchase and use only products that are specifically labeled for this pest, read and follow all label directions, and use safety equipment.
9. Are there any non-toxic methods of boxelder bug control?
According to the University of Wisconsin Cooperative Extension, a solution of 1/2 cup dish soap to one gallon of water can kill boxelders when sprayed directly on the bugs that congregate on the exterior of your home.
However, this will not have a residual effect but would need to be reapplied every time the bugs gather.
10. How can I prevent boxelder bugs from coming into my home?
The best prevention is to inspect your home for ways these bugs (and other pests) can be getting in, then build out the bugs by screening or caulking all cracks, crevices, gaps, and openings in your home; repairing any torn or broken door or window screens, and ensuring doors and windows are well-sealed; employing other exclusion techniques to reduce entry points and numbers.
11. Is there any way to permanently keep the bugs away from my home?
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, but this is not always practical or possible.