What Boxelder Bugs Look Like
- Adults: About half an inch long, dark gray to black, with red or orange lines along the edges of the wings and on the back
- Young bugs (nymphs): Smaller and bright red, with black markings, and no fully developed wings
- Where they gather: In large groups on sunny walls, fences, tree trunks, windows and door frames, especially on the south and west sides of a house
Boxelder bugs are often mistaken for other insects. If you see clusters of red and black bugs in fall, they are most likely boxelder bugs.
Why You See Them on Your House
Boxelder bugs feed on the seeds of boxelder trees, and also on maple and ash trees. Downers Grove has many maples and other mature trees around homes, and that gives boxelder bugs plenty of food close to where you live.
In late summer and fall, as the weather cools, the bugs leave the trees to find a warm place to overwinter. They gather on sun warmed walls, then squeeze into gaps in siding, around windows and doors, under fascia and into attics and wall spaces.
What Boxelder Bugs Do to Your Home
They do not bite people or harm your house. They do not eat wood, breed indoors or carry disease.
They are a nuisance. Large numbers indoors, especially on warm winter days when they wake up, are hard to live with.
They leave stains. Their droppings can leave small reddish brown spots on curtains, walls and fabrics.
They smell when crushed. Squashing them can leave a stain and an unpleasant odor, so it is best to vacuum them up.
When Boxelder Bugs Show Up
- Late summer and early fall: Groups gather on outside walls, and the bugs start looking for ways in
- Fall and winter: They hide in walls and attics. On warm, sunny days in winter they wake up and come out into rooms
- Spring: They leave your house to return to trees, and you may see them heading out through windows
The best time to treat is late summer to early fall, before they gather. Once they are inside walls, it is much harder to remove them.
How We Control Boxelder Bugs
1. Inspection. We look at the sunny sides of your home, gaps in siding, windows, doors, vents and rooflines, and check for nearby trees the bugs feed on.
2. Exterior treatment. We treat the outside of the home where the bugs gather and where they try to enter, to reduce the number that make it in.
3. Seal entry points. We point out gaps that need sealing, such as around windows, doors, utility lines, siding, fascia and vents.
4. Advice for indoors. We explain how to handle the bugs that get inside.
Because boxelder bugs are a seasonal problem, timing matters. Treatment before they gather works better than treatment after they are inside.
What to Do if Boxelder Bugs Are Already Inside
- Vacuum them up. This is the cleanest way to remove them without stains or smell. Empty the vacuum outside afterward
- Do not crush them. Crushed bugs stain and smell
- Do not use sprays or bug bombs indoors. They do not reach bugs hiding in walls, and dead bugs left in wall voids can attract other pests
- Seal gaps around windows, doors, pipes and vents when the bugs are not active
Ways to Lower Boxelder Bug Problems
- Caulk gaps around windows, doors, siding, fascia and utility entries
- Repair damaged window and door screens
- Add or replace door sweeps
- Seal attic vents with fine mesh
- Rake up leaf litter and seed pods close to the house
- If you have a female boxelder tree near the house, ask an arborist about your options, since female trees produce the seeds the bugs feed on
Boxelder Bug Control Across Downers Grove
We treat boxelder bugs in homes and businesses throughout Downers Grove, including ZIP codes 60515 and 60516, and in nearby towns such as Lisle, Woodridge, Westmont and Darien. If you are close by, call us anyway.
Frequently Asked Questions
Are boxelder bugs harmful?
Not to people or homes. They do not bite, sting or damage the structure. They can stain fabrics and smell when crushed, and large numbers are a nuisance.
Why are there so many boxelder bugs on my house?
They gather on warm, sunny walls in fall while looking for a place to spend winter. Homes near boxelder, maple or ash trees often see more of them.
Why are boxelder bugs in my house in winter?
They spend winter in walls, attics and other sheltered spaces. On warm days they wake up and move toward the light, which can bring them into rooms.
Will boxelder bugs come back every year?
They can, especially if there are host trees nearby. Treating the outside of your home in late summer, sealing gaps and keeping up with maintenance can reduce how many get in.
Can I spray them myself?
A soapy water spray can knock down bugs on the outside of your home. But it does not stop new ones from arriving or reach those hiding in walls. Professional exterior treatment before they gather works better.
What is the difference between boxelder bugs and stink bugs?
Boxelder bugs are slim and black with red lines. Stink bugs are shield shaped, mottled brown and give off a strong odor. Both invade in fall. See our Stink Bug Control page.
Is boxelder bug treatment safe for children and pets?
Your technician follows the product label and explains where products were applied and how long to keep children and pets away from treated areas.
Related services: Stink Bug Control | Asian Lady Beetle Control | Home Pest Protection Plan