Stop the fall swarm before it moves into your walls for the winter.
If there's a boxelder tree (also called an ashleaf maple) on or near your property, autumn in Wisconsin usually brings the swarm: hundreds of black-and-orange bugs sunning themselves on south- and west-facing walls, looking for a way inside to overwinter. Once they slip behind siding and into wall voids, they'll keep emerging into your living space all winter long.
Strib Pest Control provides eco-friendly box elder bug control across the Madison area — organic and low-impact treatments that knock down the swarm without dousing your home in harsh chemicals.
Adult box elder bugs are about 1/2 inch long, dark gray-black with distinctive red-orange lines on the wings and abdomen. They feed on the sap of boxelder, maple and ash trees (without harming them) and are easy to recognize — if you spot one, there are usually many more nearby.
Watch for these patterns:
They're often confused with stink bugs, since both emit an unpleasant odor when crushed — but stink bugs have a broader, shield-shaped body with mottled brown or green coloring.
Box elder bugs are harmless to people, pets and plants — they don't bite, sting or reproduce indoors. The problem is sheer volume and mess: overwintering clusters stain curtains, window ledges and walls with their excrement, and crushing them releases a foul odor. A heavy swarm can also mean hundreds of insects emerging inside your home on every warm winter day.
The most effective window for treatment is late September to early October, just before the bugs begin massing on your walls. We apply a targeted perimeter treatment to south- and west-facing exterior surfaces and known entry points, leaving a residue that keeps controlling the population for weeks. Our IPM approach prioritizes non-toxic and organic methods first, and we identify the structural gaps the bugs are using so they can be sealed.
For bugs already inside, vacuuming is safer than crushing (no stains, no odor) — and our interior treatments target the voids where they're hiding.
Late September to early October, before the bugs begin swarming on warm walls. Once they are inside your wall voids for the winter, exterior treatment is far less effective — timing matters more with this pest than almost any other.
No. They do not bite, sting, breed indoors or damage structures. Their main offense is staining walls, curtains and window ledges — and showing up by the hundreds.
No, though they are often confused because both release a foul odor when crushed and both overwinter in homes. Stink bugs are broader and shield-shaped with mottled brown-green coloring; box elder bugs are slimmer, black with red-orange markings.
Fast, honest, guaranteed pest control across Madison and Dane County.
