Eastern Boxelder Bugs are one of the most common nuisance pests across much of the United States!
As soon as cooler weather sets in, these black-and-red insects swarm the sunny sides of homes, garages, and sheds. Harmless to people, pets, and most plants, Boxelder Bugs become a problem when they gather in massive numbers and slip inside through the tiniest cracks.
They don't bite, sting, or spread disease, but their presence indoors is far from pleasant. Crush one on the carpet or couch, and you'll be left with permanent stains. Their droppings also leave behind unsightly marks on walls, curtains, and siding!
So what's a gardener or homeowner to do?
- Native or Invasive?
- Why They Gather
- Care & Maintenance - Prevention Tips
- Natural vs. Chemical Control
- Bugging Out
Native or Invasive?
The Eastern Boxelder Bug (Boisea trivittata) is native to North America and has been part of the ecosystem for centuries. They're most common east of the Rockies but can be found across much of the U.S., wherever Boxelder (Acer negundo) and related Maple and Ash trees grow.
While they aren't invasive in the ecological sense, they have adapted very well to human environments and become problematic primarily because of their swarming behavior in fall and winter.
Boxelder Relatives
Boxelder Bugs are part of the same family as several other seed-feeding insects:
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Western Boxelder Bug (Boisea rubrolineata) - Found mainly in the western U.S., very similar in appearance and habits to the Eastern Boxelder Bug, just more regionally distributed.
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Soapberry Bugs (Jadera species) - Closely related, these bugs are often found on Soapberry trees in the southern U.S. and tropics. They share the same bright red-and-black coloring and cluster in large numbers.
- Milkweed Bugs (Oncopeltus fasciatus) - Another red-and-black seed bug that resembles Boxelder Bugs but feeds on Milkweed seeds. Gardeners often mistake them for Boxelder Bugs at first glance.
Like Boxelder Bugs, these relatives are generally harmless to humans and pets, though they can sometimes become nuisance pests when populations boom.
Why They Gather
Boxelder Bugs thrive on warmth and light!
In late summer and fall, they feed on Boxelder, Maple, and Ash trees, but in such small amounts you'll likely not even notice their presence. Then, as autumn arrives, they begin to cluster on sunny, south-facing surfaces as temperatures drop!
Once the weather cools further, they search for winter shelter, often squeezing into homes, sheds, and garages. Adults typically overwinter under rocks or bark, but sometimes under your home's siding, while nymphs hide beneath leaf litter and debris.
This natural survival instinct is what leads to the overwhelming swarms many homeowners see each fall.
Care & Maintenance - Prevention Tips
The most effective control is keeping them from getting inside. Here's how to fight back:
- Seal cracks, gaps, and crevices around siding, trim, windows, and doors.
- Replace worn weatherstripping and repair torn window and door screens.
- Vacuum up indoor pests instead of squishing them to avoid stains and odors.
- Clean up fallen leaves, seeds, and debris outdoors if Boxelder are an issue in your area.
- Spray clusters off your siding with a garden hose before they find entry points.
Natural vs. Chemical Control
Boxelder Bugs are more of a nuisance than a threat, so heavy chemical treatments usually aren't necessary. Here are safer, more effective options:
- Soapy water sprays – A simple solution of dish soap and water kills Boxelder Bugs on contact. Use a spray bottle on clusters outdoors.
- Insecticidal soaps – These are commercially available, safe for use around kids and pets, and effective against soft-bodied insects like nymphs.
- Diatomaceous earth – Sprinkling this natural powder near entry points or foundations can deter crawling bugs.
- Chemical sprays – If infestations are extreme, residual insecticides applied outdoors by a professional may help. These should be a last resort, as prevention and natural methods are usually enough.
Natural Predators and Beneficial Insects
Even though Boxelder Bugs seem overwhelming when they gather in the fall, Ma Nature does provide some checks and balances. A few predators help keep their numbers down:
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Beneficial insects - Assassin bugs, praying mantises, and spiders will eat Boxelder Bugs when they can catch them.
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Birds - Starlings, crows, and some smaller songbirds occasionally feed on them, though the bugs' unpleasant taste means they aren't a preferred snack. Chickens will sometimes peck at them if they find them outdoors.
- Rodents - Mice and chipmunks may eat nymphs under leaf litter, but they aren't a major control factor.
Encouraging biodiversity in your garden by planting native flowering plants and shrubs that attract predatory insects (like Catmint, Salvia, and Russian Sage) can help maintain balance.
Bugging Out
Boxelder Bugs may not pose a real threat, but their sheer numbers make them one of fall's most frustrating invaders. With smart prevention and a little maintenance, you can keep them where they belong – outdoors.
Happy Planting!
