Brown Marmorated Stink Bugs in Michigan Homes

The brown marmorated stink bug is an invasive insect from East Asia that moves into Michigan homes in fall to spend the winter in attics and wall voids. It does not damage the structure and it does not breed indoors, but it gives off a strong odor when disturbed and can show up in large numbers. Sealing gaps before late September is the single most useful step a homeowner can take.

How to Identify a Brown Marmorated Stink Bug

Adults are shield-shaped and about five-eighths of an inch long, with a mottled brown and gray back. Two marks set this species apart. The outer edge of the abdomen shows alternating light and dark bands, and the antennae carry pale bands. The underside is lighter in color than the back.

Michigan has native stink bugs too, including green and brown species. Native stink bugs are much less likely to gather on houses and move indoors in large groups, so a crowd of brown, shield-shaped bugs on your siding in fall is usually the brown marmorated stink bug.

Where This Stink Bug Came From

The brown marmorated stink bug is native to East Asia. It was first identified in the United States in Allentown, Pennsylvania, in the late 1990s and has since spread to most of the country, including Michigan. Outdoors it feeds on many fruits and vegetables, such as apples, peaches, tomatoes, peppers and sweet corn, which is why growers track it closely.

Why Stink Bugs Move Indoors in Fall

Shorter days in September and October send adult stink bugs looking for a protected place to overwinter. On warm afternoons they collect on the south and west sides of homes, then squeeze through gaps around windows, doors, siding, soffits, chimneys and utility lines. Inside, they rest in wall voids and attics through the cold months. Warm spells wake some of them, and those bugs drift toward windows and lights in the living space, often flying slowly and noisily around lamps.

Signs of a Stink Bug Problem

How to Keep Stink Bugs Out

1. Seal early. Caulk gaps around window and door frames, siding joints, chimneys, and the places pipes, wires and vents enter the house, ideally by early September.
2. Screen the attic. Repair window screens and make sure soffit, gable and roof vents are screened, since stink bugs often enter high on the house.
3. Close door gaps. Fit door sweeps and replace worn weatherstripping and garage door seals.
4. Pull window air conditioners. Remove window units for the winter, or seal around them, because the frames leave gaps.
5. Remove, do not crush. Vacuum indoor stink bugs or drop them into soapy water, then empty the vacuum outside.

The same gaps let in mice, boxelder bugs and spiders. The fall pest-proofing checklist for Michigan homes covers all of them in one pass.

How BTR Handles Stink Bugs

Stink bugs are on the list of pests BTR's General Pest Control service is designed to prevent. The service can be booked for the interior, the exterior, or both. A visit starts with an inspection for entry points, followed by a perimeter treatment outside and targeted applications in cracks and crevices inside where needed.

BTR's Seasonal Package includes three visits across the year, with an interior focus on overwintering pests such as stink bugs. BTR uses EPA-approved products and never treats pollinating plants. Ask which warranty terms apply to your service when you book, and see the warranty page for the published terms.

Stink Bug Questions and Answers

More Fall Pest Help

• Boxelder bugs, the other black-and-red fall invader on sunny walls
• Spider control for the fall spider season
• Pre-winter rodent exclusion checklist
• Fall pest control in Michigan and the Michigan seasonal pest calendar

BTR Pest Control is based in Livonia and serves homes and businesses in Wayne, Oakland, Washtenaw, Macomb and Livingston Counties, Michigan. See all areas BTR serves.