If you've noticed black-and-red bugs gathering on the sunny side of your house in Bayonne, or a few slow-moving bugs showing up at your windows on a mild winter day, there's a good chance you have boxelder bugs. They're a classic fall nuisance pest. They don't bite, chew wood or breed inside your home, but they can show up in large numbers and they're hard to get rid of once they're in your walls. Below, we'll cover how to recognize them, why they come inside and what keeps them out. If they're already a problem, our boxelder bug control service can help.
What Boxelder Bugs Are
Boxelder bugs are plant-feeding true bugs. They get their name from the boxelder tree, a type of maple, and they feed mostly on its seeds. Female boxelder trees, the ones that produce seeds, are the main draw. They also feed on other maples and some other trees. During the warm months they live outdoors on and around these trees, and most people never notice them. It's only when the weather cools that they start looking for shelter, and that often means your house.
Signs You Have Boxelder Bugs
- Clusters on sunny walls in fall. As days get cooler, boxelder bugs gather in groups on south- and west-facing siding, foundations, fences and tree trunks that soak up afternoon sun.
- Bugs around windows and door frames. They crawl into gaps around frames, siding, vents and utility lines.
- Bugs indoors on warm winter days. Bugs hiding in your walls and attic can wake up when the sun warms that side of the house. They wander toward light and end up on windows, walls and ceilings.
- Bright red nymphs in summer. Young boxelder bugs are small and mostly red. You may see them on the ground or on tree trunks near their host trees.
- Small stains. Their droppings can leave reddish or dark spots on curtains, walls and light-colored fabric.
How To Identify A Boxelder Bug
Adult boxelder bugs are about half an inch long, with a flat, narrow body. They're mostly black, with red or orange lines on the area behind the head and along the edges of the wings. When the wings are spread, the abdomen underneath is red. Two other fall invaders are often mistaken for them.
| Boxelder Bug | Stink Bug | |
|---|---|---|
| Shape | Long, narrow and flat | Wide and shield-shaped |
| Color | Black with red or orange markings | Mottled brown or gray |
| Odor when crushed | Mild, unpleasant smell | Strong, well-known odor |
| Behavior in fall | Gathers on sunny walls, enters gaps | Gathers on walls, enters gaps |
Ladybugs (lady beetles) also cluster on siding in fall, but they're round and dome-shaped, not flat and narrow.
Are Boxelder Bugs Harmful?
Boxelder bugs are mostly a nuisance. They don't damage wood, wiring or the structure of your home. They don't reproduce indoors during winter, so the number inside won't grow until spring. They rarely bite people, and they don't carry diseases. The main problems are the sheer number of bugs, the stains they can leave and the smell when they're crushed. Outside, they cause little or no meaningful harm to healthy trees.
In spring, the bugs that survived the winter inside your walls head for windows and doors as they try to get back outside. That's often when people notice them most, and it's a sign they found a way in the previous fall.
How To Keep Boxelder Bugs Out
Timing matters most. The best work happens in late summer, before the bugs start looking for a winter home.
- Seal cracks and gaps. Caulk gaps around window and door frames, siding, trim, and where pipes, cables and vents enter the house.
- Fix screens and weatherstripping. Repair torn window screens, add door sweeps and replace worn weatherstripping.
- Screen vents. Cover attic, soffit and gable vents with fine mesh.
- Vacuum, don't squash. Indoors, vacuum bugs up and empty the bag or canister outside. Crushing them can leave stains and odor.
- Wash clusters outside. Soapy water sprayed directly on clusters on siding kills the bugs it hits without harsh chemicals.
A full seal-up with our home pest-proofing service closes the entry points that also let in stink bugs, ladybugs and other fall invaders.
When To Call A Professional
Call a pro when bugs keep showing up indoors all winter, when large clusters return to the same walls every fall or when entry points are high on the house and hard to reach. EcoFusion's NJ DEP-licensed technicians inspect for entry points, seal what we can and apply targeted exterior treatments with EPA-registered, eco-safe products before the bugs move in. Once they're settled inside wall voids, treating them there is rarely practical, which is why the focus is on keeping them out in the first place.
Boxelder bugs are easy to recognize once you know their black-and-red pattern and their habit of sunning on walls in fall. Seal up early, vacuum the stragglers and you'll see far fewer of them. If they're already wintering in your Bayonne home, EcoFusion Pest Control can inspect and help keep them out next season.