Boxelder bug facts and identification

Boxelder bugs (Boisea trivittata) are common pests that gather in large groups on trees and buildings. In the fall, they look for warm places to overwinter, often invading homes. While they do not bite or damage property, they can be a nuisance. Their excrement can stain walls and furniture, and when crushed, they release an unpleasant odor.

Boxelder bug identification

Boxelder bugs are easy to recognize by their black bodies and red markings. Knowing what they look like and the signs of an infestation can help you keep them out of your home.

Signs of a boxelder bug infestation

Boxelder bugs often gather in large numbers on siding, windows, and trees. In fall, they move toward homes, looking for entry points like cracks and crevices. If they get inside, they may stain fabrics and walls with their droppings. You might also notice them sunbathing on warm walls before they find a way indoors.

Habitat, diet, life cycle and behaviors

Boxelder bugs live on trees, feed on plant juices, and seek shelter indoors when it gets cold. 

Where do boxelder bugs live?

Boxelder bugs live on boxelder trees, maple trees, and ash trees. In warm months, they stay on these host trees, feeding on leaves and seeds. When the weather cools, they invade buildings, looking for a safe place to survive the winter.

Diet

Boxelder bugs eat seeds, leaves, and flowers from their host trees. They use their piercing-sucking mouthparts to drink plant juices. These insects prefer female boxelder trees because they drop more seeds.

Life cycle

Boxelder bugs go through three stages: egg, nymph, and adult. In spring, females lay tiny eggs on trees. In just a few days, the eggs hatch into nymphs, which grow into adults by late summer. As temperatures drop, boxelder bug adults seek shelter to overwinter.

Behaviors

Boxelder bugs gather in warm places like rocks, tree trunks, and buildings. They like to sunbathe and can often be found on walls, windows, and siding. If they get inside, they won’t reproduce, but they can be annoying. If disturbed, they may release a bad smell.

Are boxelder bugs dangerous?

Boxelder bugs are not harmful to people or pets. They don’t bite, sting, or carry diseases. However, they can stain walls, furniture, and clothing with their droppings. Crushing them can also leave a bad odor. While they are mostly a nuisance pest, they can be frustrating when they gather in large groups inside a home.

How to get rid of boxelder bugs?

The best way to stop boxelder bug infestations is to seal cracks and entry points in your home. Use caulk around windows and doors, and check for gaps in siding. If they are already inside, use a vacuum to remove them instead of crushing them. Reducing host trees (boxelder, maple, and ash) near your home can also help.

Boxelder bug prevention tips

Follow these steps to keep boxelder bugs out of your home:

1. Seal cracks in doors, windows, and walls
   Boxelder bugs sneak in through tiny cracks. Check around doors, windows, and your home’s foundation for gaps. Use caulk or weather stripping to seal them.
2. Fix window screens
   Make sure your window and door screens don’t have holes. If they do, repair or replace them so bugs can’t crawl inside.
3. Clean up seeds and leaves from boxelder trees
   Boxelder bugs love boxelder trees. Rake up fallen seeds and leaves to make your yard less inviting to them. Trim back tree branches near your home to keep bugs away.
4. Use safe pest control methods
   Try using insecticidal soap or diatomaceous earth to keep boxelder bugs under control. If they become a big problem, call our pest control experts for help.

Need help with insect pest control?

If boxelder bugs have taken over your home, our professional insect control experts can help. They know where to look for hiding bugs and can treat problem areas to stop the infestation.

Other insects

Learn more about other insect pests with our insect information guide.

Frequently asked questions