How to Get Rid of Boxelder Bugs on Long Island (and Why They Swarm in Fall)

To get rid of boxelder bugs on Long Island, treat the exterior of your home with a professional perimeter barrier in early fall — before they cluster on sunny walls and move inside to overwinter. Seal cracks around windows, doors, and vents to block entry, and vacuum (never crush) any bugs already indoors. Boxelder bugs don’t bite, sting, or damage your home — but once they settle into wall voids for winter, they’re hard to remove, so timing the treatment for late summer is what actually solves it.

What are boxelder bugs?

Boxelder bugs (Boisea trivittata) are about half an inch long, black with three distinctive red-orange stripes on the back and red-outlined wings. Young nymphs are bright red. They’re named for the boxelder tree, but they also feed on the seeds and leaves of maple and ash trees — all common across Nassau and Suffolk County. Through spring and summer they live outdoors on those trees and go mostly unnoticed. You only really meet them in fall, when they gather in large numbers on the outside of homes. They are a true “occasional invader” — a nuisance pest that comes indoors seasonally rather than living or breeding inside.

Why are boxelder bugs all over my house in the fall?

As Long Island nights cool in September and October, boxelder bugs look for a warm place to spend the winter. They’re drawn to heat, so they gather on the south- and west-facing walls of homes that catch the afternoon sun. Once they’re clustered on the warm siding, they work their way inside through the smallest gaps — around window frames, door trim, utility penetrations, soffits, and attic vents — and settle into wall voids and attics to wait out the cold in a dormant state. On warm winter days, and again in spring, some wake up and wander into living spaces, which is when most homeowners notice them at the windows. Homes near boxelder, maple, or ash trees see the heaviest activity.

Are boxelder bugs dangerous? Do they bite?

No. Boxelder bugs do not bite people or pets, they don’t sting, and they don’t spread disease. They also don’t damage the structure of your home, chew wood, or reproduce indoors — so an indoor cluster won’t grow into an infestation the way ants or roaches would. They are almost entirely a nuisance. The two real annoyances: if you crush them, they release a foul odor and can leave an orange-red fecal stain on curtains, walls, and light-colored surfaces. That’s why the golden rule indoors is vacuum, don’t squish.

How to get rid of boxelder bugs

Because these bugs invade from the outside, the fix is an outside-in approach:

• Time it for late summer / early fall. The single most effective step is a professional exterior barrier treatment applied to the foundation, siding, eaves, and around entry points before the bugs cluster (roughly late August through September on Long Island). This treats them at the walls, where they gather, instead of after they’re already inside.
• Seal their entry points. Caulk gaps around window and door frames, seal where pipes and cables enter, repair torn screens, and screen off attic and soffit vents. Fewer openings means fewer bugs indoors — this year and next.
• Vacuum the ones inside. Use a vacuum (ideally with a disposable bag) to remove bugs at windows and in corners. Don’t crush them, and skip the DIY sprays indoors — they don’t address the source and can stain.
• Skip the “spray the tree” idea. Treating the boxelder or maple trees themselves is rarely practical or effective; the perimeter of the house is what matters.

How do I keep boxelder bugs from coming back next year?

Boxelder bugs are creatures of habit — a home that clusters them one fall will usually attract them again. Lasting control is about making the exterior less welcoming: keep up the fall perimeter treatment each year, stay ahead of new gaps as caulk and weatherstripping age, and keep vents and screens intact. Some homeowners with heavy pressure choose to remove a nearby female boxelder tree over time, but that’s a big step and rarely necessary when the perimeter is handled. A recurring exterior program is what keeps the fall wave off the walls year after year.

When to call a Long Island pest professional

If boxelder bugs are covering your siding every fall, showing up indoors through the winter, or you simply want them handled before the October surge, that’s the point to bring in a pro. At Battle A Bug, we’ve been treating occasional invaders across Nassau County and Western Suffolk since 1996. Owner Victor Bonavita is a past president of both the New York Pest Management Association and the Long Island Pest Control Association, and our team times exterior barrier treatments to Long Island’s fall season so the bugs are stopped at the wall — not after they’ve moved in. We treat the source and back our work with a warranty.