Boxelder Bug
Boisea trivittata
Scientific illustration for identification purposes
Overview
Boxelder bugs are black insects with distinctive red-orange markings. They congregate in large numbers on sunny walls in fall, seeking warmth before winter. While harmless, they can be a significant nuisance when they enter homes.
How to Identify
- Elongated oval body about 1/2 inch
- Black with red-orange markings on wings
- Three red stripes behind head
- Red eyes
- Flattened wings when at rest
Behavior
Boxelder bugs congregate on sunny sides of buildings in fall, seeking warmth. They enter homes through gaps to overwinter. They do not bite, damage structures, or reproduce indoors.
Habitat
Feed on boxelder trees (primarily), maples, and ash trees. In fall, they seek warm overwintering sites including building walls and interiors.
Diet
Feed on seeds, leaves, and flowers of boxelder trees and related maples. Do not feed indoors.
Reproduction
Two generations per year. Eggs laid on boxelder trees in spring. Adults emerge in summer and seek overwintering sites in fall.
Distribution in the Southern U.S.
Common throughout Texas, Oklahoma, Louisiana, and Mississippi where boxelder and maple trees grow.
Regional Notes
In the South, they may be active on warm winter days. Large congregations on south-facing walls are common in fall.
Signs of Infestation
- Large numbers of bugs on sunny exterior walls
- Bugs entering through gaps around windows
- Dead bugs accumulating inside windows
- Bugs active on warm winter days
- Red staining when bugs are crushed
Prevention Tips
- Seal gaps around windows and doors
- Install door sweeps
- Repair torn screens
- Caulk gaps around utility penetrations
- Consider removing nearby boxelder trees
- Vacuum bugs rather than crushing (stains)
When to Contact a Professional
Contact a professional for large fall invasions or to apply barrier treatments before bugs congregate.
Romex Pest Control provides professional boxelder bug control services across Texas, Oklahoma, Louisiana, and Mississippi.
Learn about our boxelder bug control servicesFrequently Asked Questions
Are boxelder bugs harmful?
Boxelder bugs do not bite, sting, transmit disease, or damage structures. They are strictly nuisance pests. Crushing them can leave red stains on surfaces.
Will boxelder bugs go away on their own?
Boxelder bugs that enter homes in fall will become inactive in winter. In spring, survivors will try to exit. They do not reproduce or feed indoors.
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