Boxelder Bugs (Boisea trivittata): Identification, Risks & Control

Boxelder Bug (Boisea trivittata) is a striking black-and-red insect that is most commonly noticed in large clusters on warm, sunny walls during autumn. While they do not cause the same level of destruction as Carpet Beetles or Cigarette Beetles, they are considered nuisance pests because of their tendency to invade homes in large numbers when seeking shelter for the winter.

Boxelder bugs are part of the true bug order Hemiptera, which means they have piercing-sucking mouthparts. Their primary food source comes from boxelder trees (Acer negundo), as well as other maples and ash trees. Outdoors, they rarely cause significant tree damage, but indoors, their sheer numbers, unpleasant odor when crushed, and fecal staining can become a serious household problem.

This article explores how to identify, understand, and manage Boxelder Bugs, both in domestic and commercial environments.

Identification

• Adults: About 12–14 mm long, black with distinct orange or red lines along the thorax and wings.

• Nymphs: Smaller, bright red, gradually darkening as they mature.

• Wings: Fold flat over the body, forming an “X” shape.

• Behavior: Often cluster in large numbers on sunny walls, tree trunks, or rocks.

Field tip: Boxelder bugs are often mistaken for Stink Bugs, but the body shape and coloration are distinct.

Biology and Lifecycle

• Eggs: Laid in spring on leaves, bark, or seed pods of host trees.

• Nymphs: Feed on seeds and leaves of boxelder and maple trees.

• Adults: Overwinter in bark crevices, leaf litter, or inside buildings.

• Generations: Typically two per year, depending on climate.

Seasonal pattern:

• Spring: Emergence from overwintering sites.

• Summer: Feeding on host trees.

• Autumn: Migration to sheltered sites, including homes and buildings.

Ecology and Distribution

• Native to North America, especially abundant in the central and eastern United States and southern Canada.

• Associated primarily with boxelder trees but also found on maples and ash.

• Thrive in suburban and rural environments where ornamental maples are planted.

• In Europe, reports are rarer but related Hemipterans occupy similar ecological niches.

Risks and Damage

Unlike Aphids or Thrips, boxelder bugs do not transmit plant viruses or significantly reduce crop yield. However, they still present several risks:

• Household nuisance: Large clusters enter buildings during fall.

• Odor: Release a strong smell when crushed.

• Staining: Fecal spots can discolor walls, curtains, and furniture.

• Psychological impact: Large numbers indoors can cause distress.

For businesses, especially hotels, offices, and public institutions, infestations can damage reputation even if they cause little structural damage.

Signs of Infestation

• Large numbers of red-and-black bugs clustering on warm walls or windows.

• Presence of red nymphs around trees or gardens in summer.

• Bugs found inside attics, basements, or living spaces in autumn and winter.

• Stains on fabrics or walls caused by excrement.

Household Control

• Exclusion: Seal cracks, repair screens, close vents, and caulk entry points.

• Vacuuming: Safe and effective way to remove indoor bugs.

• Trapping: Light traps in attics and unused rooms may reduce numbers.

• Insecticidal soap or sprays: Can be applied outdoors to reduce populations on walls or trees.

• Professional help: Necessary if infestations are overwhelming.

Tip: Avoid crushing them indoors, as this releases odors and stains.

Outdoor and Professional Control

• Tree management: Removal of female boxelder trees (which produce seeds) reduces food sources.

• Chemical sprays: Residual insecticides applied to exterior walls and around entry points in late summer may prevent autumn invasions.

• Monitoring: Regular checks during fall migration season.

• Integrated Pest Management (IPM): Combining exclusion, sanitation, and targeted chemical use provides the best long-term results.

Some pest control professionals treat boxelder bugs similarly to Asian Lady Beetle and Stink Bug infestations—focusing on preventing entry rather than eradication.

Final Thoughts

The Boxelder Bug (Boisea trivittata) is not the most destructive pest, but it is one of the most recognizable nuisance insects across North America. Their tendency to swarm in large numbers, stain surfaces, and invade homes makes them a seasonal frustration for homeowners and businesses alike.

Compared to storage pests such as the Cigarette Beetle (Lasioderma serricorne) or Drugstore Beetle (Stegobium paniceum), boxelder bugs are relatively harmless to food and stored products. However, they are similar to Stink Bugs and the Asian Lady Beetle, since all three are primarily outdoor insects that invade indoor spaces during colder months.

The best strategy against boxelder bugs is prevention. By sealing cracks, maintaining proper screens, and treating exteriors before autumn, you can reduce infestations dramatically. For larger problems, professional pest management ensures thorough exclusion and minimizes risks of odor and staining.

As climate conditions change and warmer autumns extend insect activity, boxelder bugs may become even more common in urban areas. Staying proactive with monitoring and prevention will keep them from becoming more than a nuisance.

Read more in our blog and explore guides on many other enemies. Stay informed.

Disclaimer

This article is for informational purposes only. Pest control laws and approved chemicals vary by country. For best results and legal safety, we strongly recommend contacting a licensed pest control professional in your local area. Always make sure that the pest control technician is properly certified or licensed, depending on your country’s regulations. It’s important to confirm that they only use approved products and apply them exactly as instructed on the product label. In most places in Europe, UK, or USA, following label directions is not just best practice—it’s the law.

Author

Nasos Iliopoulos
MSc Agronomist & Certified Pest Control Expert
Scientific Director, Advance Services (Athens, Greece)
Licensed Pest Control Business – Ministry of Rural Development & Food (GR)

References

• University of Minnesota Extension – Boxelder Bugs

• Wikipedia – Boisea trivittata