Central Iowa Pest Guide
Boxelder Bugs in Des Moines: Why They Swarm and How to Stop Them
Boxelder bugs are the black-and-red insects that blanket sunny walls of Des Moines homes on warm fall days. They are a nuisance only, but they can enter by the hundreds.
What Are Boxelder Bugs?
Boxelder bugs (Boisea trivittata) are about a half inch long, black with three orange-red stripes on the thorax and red-edged wings. Nymphs are bright red.
They feed mostly on the seeds of female boxelder trees, and secondarily on maple and ash, so nearby seed-bearing trees drive local populations.
They do not bite, sting, damage structures, or reproduce indoors. Their droppings can stain curtains, siding, and light-colored surfaces.
Like stink bugs, they overwinter in sheltered wall voids and attics and reappear during warm spells.
Signs of Boxelder Bugs in Your Home
- Large clusters on south- and west-facing walls, foundations, and sidewalks on sunny autumn days
- Black-and-red adults with bright red nymphs mixed in during summer
- Bugs appearing at windows inside the home in late winter and early spring
Why Boxelder Bugs Matter
Purely a nuisance and staining issue, but the sheer numbers make them one of the most complained-about fall pests in central Iowa.
When Boxelder Bugs Are Active in Central Iowa
Populations build on host trees through summer, adults congregate on structures in September and October, and they trickle indoors through winter and out again in March.
Home Remedies & DIY Control
- 1Seal cracks and gaps in siding, around window and door frames, soffits, and utility penetrations before early fall.
- 2Install or repair screens on windows, attic vents, and gable vents, and add door sweeps.
- 3Spray clusters on siding directly with a solution of a few tablespoons of dish soap per gallon of water. Soap kills on contact and is inexpensive; it has no lasting residual, so repeat as clusters reform.
- 4Hose bugs off walls and foundations with a strong jet of water on warm afternoons.
- 5Vacuum indoor bugs and empty the canister outdoors. Avoid squashing them, which stains.
- 6Consider removing or replacing female (seed-bearing) boxelder trees near the home if the problem is severe and recurring — this is the long-term fix.
- 7Rake up and dispose of boxelder seeds from the lawn in fall.
When to Call a Professional
An exterior perimeter treatment applied in late summer, before the bugs cluster, is the standard professional approach and works best combined with sealing.
Voice calls only — this line does not receive text messages
Government & University Sources
- Iowa State University Extension — Boxelder Bugs
- University of Minnesota Extension — Boxelder Bugs
- U.S. EPA — Introduction to Integrated Pest Management
This article is general educational information for central Iowa homeowners, not professional, medical, or legal advice. Always read and follow pesticide label directions.