True bugs · Halyomorpha halys
Brown marmorated stink bugs
Brown marmorated stink bugs are invasive, shield-shaped brown insects that crowd onto houses in fall looking for a place to spend the winter. They don't bite, sting, breed indoors or damage the house, but they release a strong odor when disturbed. They're a common fall and winter nuisance across Southeast Tennessee and North Georgia.
Seasonal activity
When they're active in Southeast Tennessee
Stink bugs are gathering on sunny walls and slipping into attics and window frames for winter.
- January: Low
- February: Moderate
- March: Moderate
- April: Moderate
- May: Low
- June: Inactive
- July: Inactive
- August: Low
- September: Peak
- October: Peak
- November: Moderate
- December: Low
Signs
How to tell you have them
- Clusters of brown shield-shaped bugs on the sunny side of the house on warm fall afternoons
- Bugs crawling around windows, door frames, light fixtures and ceiling fans
- Sluggish bugs appearing indoors on warm winter or early spring days
- A sharp, unpleasant smell when bugs are crushed or vacuumed
- Dead bugs collecting in attics, window sills and light covers
Why they show up in winter
Brown marmorated stink bugs arrived from Asia in the 1990s and have since spread through much of the eastern U.S., including our area. Unlike our native stink bugs, they look for man-made shelter to spend the winter. Starting in September and running through October, adults gather on sunny walls and squeeze through gaps around windows, siding, soffits and vents into attics and wall voids.
Once inside the walls, they go dormant. On warm winter days and in early spring, the heat wakes some of them up, and instead of finding their way back outside they wander into living spaces. That's why you can see stink bugs in January even though none came in that day. They leave on their own in April and May to feed and breed outdoors.
They don't reproduce indoors, eat wood or fabric, or bite. The real issues are the smell and the numbers. Large numbers dying inside walls can also attract carpet beetles, which then move on to wool, pet food and pantry goods.
How we treat them
Sealing the house before they arrive does more than anything sprayed afterward.
- 01
Find the entry points
We look at the gaps they use most: around window and door frames, siding and trim, soffits, attic and gable vents, and utility penetrations.
- 02
Exclusion recommendations
We point out what to caulk, screen or weatherstrip, ideally in late summer before the fall flight starts.
- 03
Exterior perimeter treatment
A treatment on exterior surfaces where bugs gather, timed for early fall, can reduce how many get in. Residual effect outdoors is short, so timing matters.
- 04
Indoor advice, not indoor spraying
Extension specialists don't recommend spraying insecticides indoors for stink bugs. We'll walk you through removal that doesn't leave odor or dead bugs in the walls.
Prevention
What you can do today
- Caulk gaps around window and door frames, siding, trim and where pipes and wires enter the house
- Repair or replace damaged window and door screens and add door sweeps
- Screen attic, soffit and gable vents
- Do sealing work in late summer, before bugs start gathering in September
- Vacuum indoor bugs with a shop vac or a dedicated handheld vacuum, not your main one, and empty it outside
- Or knock them into a container of soapy water, where they drown
- Don't crush them indoors, and don't release them outside the door; they'll just come back in
When to call us
Pest control
Inspection-first treatment for the everyday pests that get into Tennessee and North Georgia homes.
How we treat itQuestions
Brown marmorated stink bugs FAQ
Why do I have stink bugs inside in winter?
They moved into your walls or attic last fall to wait out the cold. Warm days and indoor heat wake some of them up, and they wander out into rooms instead of back outside. They aren't breeding in the house, and the numbers will drop off by late spring.
Do stink bugs bite or cause damage inside?
No. Their mouthparts are built for sucking plant juices, so they can't bite people or chew wood, wiring or fabric. Indoors they're a nuisance because of the smell and the numbers.
What's the best way to get rid of stink bugs in the house?
Vacuum them with a shop vac or a handheld vacuum you don't mind smelling, or drop them into a container of soapy water. A pan of soapy water under a desk lamp at night also catches quite a few. Long term, sealing gaps on the outside is what cuts the numbers.
When do stink bugs come into houses in Tennessee?
Most enter from about mid-September through October, peaking around the first weeks of fall. On sunny afternoons you'll see them gathering on the warm sides of the house before they find a way in.
Will spraying inside get rid of stink bugs?
Not really. Indoor sprays and foggers kill the few bugs they touch but don't stop more from coming out of the walls, and dead bugs in voids can attract carpet beetles. Exclusion and vacuuming work better.
References
Last fact-checked October 15, 2026.
Think you have brown marmorated stink bugs?
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