Boxelder bugs enter homes and other buildings, often in large numbers, which can be a nuisance. They do not bite people and are essentially harmless to property, but when abundant, they can stain walls, curtains, and other surfaces with their excrement. Occasionally some may seek moisture and may be found around houseplants, although they rarely attack them. In the few cases when they do feed, boxelder bugs are very unlikely to injure indoor plants.
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The best means of avoiding issues with boxelder bugs is to prevent them from entering your home to begin with. Some key measures you may want to take in early fall are as follows:
- Repair or replace damaged window and door screens.
- Repair or replace damaged screens in roof and soffit vents, and in bathroom and kitchen fans.
- Seal areas where cable TV wires, phone lines, and other utility wires and pipes, outdoor facets, dryer vents and similar objects enter buildings.
- Seal with caulk or for larger spaces use polyurethane expandable spray foam, copper mesh, or other appropriate sealant.
- Install door sweeps or thresholds to all exterior entry doors. Install a rubber seal along the bottom of garage doors.
- You may want to also supplement non-chemical methods with an insecticide treatment around the exterior of your home, especially if large number of boxelder bugs are present and/or you have a history of boxelder bug invasions.