To get rid of box elder bugs on a house, remove the ones you can see, block the gaps they use to enter, and reduce the conditions that attract them. These steps work best as a combination: spraying indoors may kill a few bugs, but it will not stop new ones from getting in.
Box elder bugs are most noticeable when they gather on sunny exterior walls, then seek sheltered places as the weather cools. They do not bite or damage a house, but they can be a nuisance indoors, and crushing them may leave a stain or an unpleasant odor. Before starting, confirm that the insects are box elder bugs, and plan to focus on exclusion and cleanup rather than broad indoor pesticide use.
What You’ll Need
- A vacuum with a hose or a soft brush and dustpan for removing insects indoors.
- Soapy water and a cloth for cleaning accessible surfaces after removal.
- Fine mesh screen or suitable weatherstripping for small openings around screens and doors.
- Exterior-grade caulk and a caulking gun for appropriate fixed cracks and gaps.
- A flashlight, gloves, and a stable step stool or ladder if needed to inspect reachable areas safely.
- A covered waste container or a sealable bag for collected bugs and vacuum debris.
Use only materials that suit the surface and opening being repaired. For work at height, on electrical equipment, or near delicate siding, ask a qualified professional rather than taking a risk.
Step-by-Step
- Check that the insects are box elder bugs. Adults are dark, flattened insects with red or orange markings, including lines around the wings. They often gather in groups on warm, sunny exterior walls, especially where box elder or other maple trees are nearby. Look at several insects rather than relying on a single glimpse. If the insects do not fit that description, avoid treating the house until you have identified them; other pests may need a different response.
- Find where they are gathering and entering. From the ground, inspect the sunny sides of the house, window frames, doors, vents, eaves, and the foundation. Note clusters and likely routes indoors, such as loose screen edges, gaps beneath doors, or openings around pipes. Check the inside of nearby windows and light fixtures for signs of entry. You do not need to dismantle walls or disturb insulation; focus on visible, accessible openings.
- Remove indoor bugs without crushing them. Vacuum visible insects with the hose attachment, then empty the canister or bag into a sealed disposal container promptly. If you do not have a vacuum handy, gently sweep them into a dustpan. Avoid squashing them on walls, curtains, or carpet because they can leave marks. Do not use a vacuum that releases dust or insects back into the room; clean it according to its instructions after use.
- Clean the areas where bugs have been found. Wipe accessible hard surfaces with a damp cloth and mild soapy water, then dry them. Test cleaning solutions on an inconspicuous spot first, especially on painted, fabric, or finished surfaces. Avoid rubbing a stain deeper into a porous material. For a stubborn mark on a delicate surface, follow that material’s care instructions or consult a cleaner.
- Seal small, fixed gaps. Close appropriate cracks around trim, siding joints, and utility penetrations with a compatible exterior sealant. Repair loose door sweeps and weatherstripping, and make sure window screens fit their frames without tears or gaps at the edges. Keep required ventilation openings clear: cover them only with a suitable screen that does not obstruct airflow. Do not seal a gap until you know it is not a necessary drain, vent, or movement joint.
- Improve screens and entry points. Repair torn mesh, secure screen frames, and check that doors close fully. Pay attention to the corners of screens and the bottom of doors, where small defects can go unnoticed. If bugs are coming through a vent or another feature that must remain open, use an appropriate fine screen or ask a building professional about a safe repair. Do not block appliance vents, combustion-air openings, or other essential airflow.
- Reduce outdoor gathering places near the house. Remove fallen leaves and other debris from close to the foundation, and keep stored items from creating sheltered piles beside walls. If a box elder tree is present, consider whether branches or seed-bearing debris are contributing to the problem, but do not assume that removing the tree is necessary. These bugs may travel from trees beyond your property, so exclusion and cleanup remain important even if you change nearby landscaping.
- Monitor and repeat the practical steps. Check the same sunny walls and indoor windows regularly while bugs remain active. Vacuum any newcomers and note whether they appear in one room or along one section of the house. A repeated cluster may point to an opening that still needs attention. After repairs, inspect screens and seals now and then, since weather and normal building movement can create new gaps.
- Use pesticides only when there is a clear reason. Many indoor infestations can be managed with removal and exclusion. If a large or persistent outdoor cluster remains, read the product label and confirm that the product is intended for the specific pest, surface, and location. Follow all label directions and precautions; do not apply an outdoor product indoors or spray food-preparation surfaces, people, or pets. When the situation is extensive or the correct treatment is unclear, consult a licensed pest-control professional.
Common Mistakes
- Relying on indoor spraying alone. It may not reach the entry route, and new bugs can continue to arrive. Seal openings and repair screens as well as removing insects already inside.
- Crushing bugs on walls or fabrics. This can leave a stain or odor. Use a vacuum or sweep them up gently instead.
- Sealing every opening indiscriminately. Some gaps serve as drains or ventilation. Identify an opening before closing it, and do not obstruct required airflow.
- Removing a tree as the first response. Nearby trees can be associated with gatherings, but bugs may come from elsewhere. Try exclusion and cleanup before making a major landscaping decision.
- Using pesticide contrary to its label. A product approved for one location may not be suitable for another. Never mix products or assume that a household insect spray is appropriate for every surface.
Tips
- Start with the wall where bugs gather most often; it can help you find the likely entry points.
- Use a flashlight to inspect screen edges, door bottoms, and gaps around pipes without pulling apart finished surfaces.
- Keep a simple note of where and when you see bugs. A clear pattern can help distinguish one overlooked opening from insects arriving at several places.
- For a rental home, tell the property manager about recurring entry points and ask before making permanent exterior repairs or applying pesticides.
- Keep children and pets away while cleaning or carrying out repairs, and follow tool and product instructions.
Troubleshooting
They keep appearing around one window. Check the screen for a loose edge or tear, and inspect the frame and nearby trim for a visible gap. Remove the insects, then repair the screen or seal a suitable fixed crack. If the window is part of a shared wall or the gap is inaccessible, ask a qualified repair professional to inspect it.
You see bugs inside but cannot find a hole. Insects may be entering through a small screen defect, a door gap, or an opening around a utility line. Inspect likely routes in the room where they appear, including nearby vents, without blocking any opening needed for ventilation. If the sightings continue, a pest professional can help identify the route.
There are many bugs on the outside wall. Remove accessible clusters with a vacuum or gentle sweeping, and clear debris near the foundation. Check nearby screens and doors. If a large cluster is difficult to reach, do not climb unsafely or spray blindly; get professional help.
They return after you seal a gap. The gap may not have been the only route, or the repair may have left an edge open. Recheck the area and inspect nearby openings. Make sure the repair material is suitable for the surface and has been applied as directed.
A stain remains after cleanup. The surface may be porous or sensitive to cleaning. Avoid scrubbing harder or trying an untested solvent. Check its care guidance, test any suitable cleaner in a hidden spot, or consult a cleaning professional.
Frequently Asked Questions
Do box elder bugs damage a house?
They do not chew wood or damage the structure. They are mainly a nuisance when they gather outside or enter sheltered indoor spaces; crushed insects can mark some surfaces.
Do box elder bugs bite?
They are not considered a biting pest. They may occasionally probe a surface, but they do not feed on household furnishings or cause structural damage.
Why do they gather on sunny walls?
They are often seen clustering on warm, sunlit exterior surfaces. They may also seek sheltered places as conditions change, which is why small gaps and screens matter.
Will removing a box elder tree solve the problem?
Not necessarily. Nearby trees can be associated with gatherings, but bugs may also come from other trees in the area. Fixing entry points and removing insects is usually a practical first response.
Can I use insecticide indoors?
Only use a pesticide indoors if its label specifically allows that use and the target pest and surface are covered. Follow the label exactly. For a persistent problem or uncertainty about safe application, contact a licensed professional.
When should I call pest control?
Consider professional help when bugs keep entering despite careful screening and sealing, when clusters are out of reach, or when you cannot identify the entry route. A professional can inspect the building and explain options for the specific location.