If the sunny side of your house is crawling with brown, shield-shaped bugs right about now, you’re not alone. Every fall, stink bugs, boxelder bugs and a few other “fall invaders” pile onto warm walls across Salem, Gloucester and Cumberland counties, looking for a way inside for the winter. They don’t wreck your house, but nobody wants them in the bedroom in February. Here’s what’s going on and how to keep them out.
Meet the Brown Marmorated Stink Bug
The stink bug most of us deal with is the brown marmorated stink bug. It’s not from around here. According to Rutgers, it’s native to Asia and was first collected in the U.S. just across the Delaware River in Allentown, Pennsylvania, in the fall of 1996. It turned up in New Jersey in 1999, spread into southern New Jersey in 2005, and is now found throughout most of the state.
You’ll know it by its mottled brown color, its shield shape and the white bands on its antennae. And you’ll definitely know it if you squish one.
Why They Show Up on Your House in the Fall
Rutgers explains that the adults behave a lot like Asian lady beetles and boxelder bugs. They gather on houses in late fall and eventually move indoors. Once inside, they hide in wall voids, attics and around window frames. On warm days in fall and winter, they wake up and wander into living spaces, which is why you’ll suddenly find one on a lampshade in January.
The good news, according to Rutgers: they don’t reproduce indoors over the winter, they barely feed, and they don’t bite people or pets. They’re a nuisance and a smell, not a health threat.
Boxelder Bugs and Other Fall Visitors
Boxelder bugs are the black bugs with red markings. Rutgers says they build up in late summer and early fall and like to gather in large numbers on sunny, south-facing spots, like your front door, before overwintering inside buildings, including attics. They used to be tied mostly to boxelder trees, but Rutgers notes they’ve been documented feeding on a long list of plants, so removing one tree rarely fixes the problem.
Rutgers also mentions hackberry psyllids, tiny black jumping insects that can gather by the hundreds near large hackberry trees in fall and will overwinter inside homes. Same game plan: keep them out.
How to Keep Fall Invaders Out
Exclusion is the name of the game. Rutgers recommends sealing up the places where these bugs gather on the outside of the house:
- Caulk gaps around windows, doors and trim.
- Replace worn weatherstripping and door sweeps.
- Check where pipes, wires, cable lines and outdoor faucets come through the wall.
- Make sure attic, soffit and foundation vents are screened and the screens are intact.
- Look at the chimney and roofline for gaps.
- Pull window air conditioners by mid-September. Rutgers calls them out as a common way in.
The south and west sides of the house get the most sun, so they usually get the most bugs. Start there.
A bonus: the same gaps that let stink bugs in let mice in too. Sealing up in the fall pulls double duty.
If They’re Already Inside
- Vacuum them up. Rutgers recommends vacuuming and disposing of them as a non-chemical way to remove them. Empty the bag or canister outside right away, or the smell will stick around.
- Don’t crush them. That’s when they release the odor.
- Rutgers does not recommend using insecticides inside the home for stink bugs. Indoor spraying isn’t the answer.
Where I Can Help
Rutgers notes that an exterior perimeter treatment may help reduce numbers if it’s done when the bugs first start showing up, which in South Jersey usually means late summer into early fall. Timing matters more than anything. When I take care of a house for fall invaders, I start with a walk-around to find where they’re gathering and getting in, point out what should be sealed, and treat the outside of the home with eco-friendly products, applied carefully.
Because the entry points overlap so much, I often look at fall invaders and mice at the same visit. Our rodent control page explains that side of it. Offices, shops and rental properties get swarmed too; see our commercial pest control page for businesses.
Tired of Bugs on the Siding?
Call me at 856-599-9376, Monday through Saturday, 8 to 6. Zero Pests is veteran-owned and serves Salem, Gloucester and Cumberland counties, including Woodstown and Pilesgrove and Swedesboro. NJ license #92354B.
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