Brown marmorated stink bugs are shield-shaped invasive insects that gather on warm walls in fall and push indoors to overwinter. They release a pungent odor when disturbed and are an increasing nuisance in Whidbey and Skagit homes.
How to identify brown marmorated stink bugs
About 5/8 inch, mottled brown, shield-shaped, with alternating light-dark bands on the antennae and abdomen edge. They give off a strong cilantro-like smell when handled or crushed.
Behavior & season on Whidbey & Fidalgo
In fall they aggregate on sun-warmed south and west walls, then slip through gaps into attics and wall voids to overwinter, re-emerging on warm days and in spring. They do not breed indoors.
Why brown marmorated stink bugs are a problem
They do not bite, sting, or damage structures, but large overwintering groups are a persistent nuisance, and crushing them releases a lasting odor. They can also damage garden and fruit crops outdoors.
Signs of brown marmorated stink bugs activity
- Shield-shaped brown bugs clustering on warm exterior walls in fall
- Bugs appearing indoors on warm winter and spring days
- A strong odor when disturbed
- Aggregations around windows and attic vents
How Salty Dog treats brown marmorated stink bugs
We treat exterior aggregation points and harborage in fall and seal the gaps they use to get in, reducing how many make it indoors. Learn more about our Outdoor Pest Control service, or browse the full Pest Library.
Reviewed by Matthew — Salty Dog Pest Control. WSDA-licensed structural pest applicator (License #101709). Veteran- and family-owned, serving Whidbey Island, Fidalgo Island, and west Skagit County.
Frequently asked questions
Why are stink bugs in my house in winter?
They enter in fall to overwinter in wall voids and attics, then wander into living space on warm days. Fall exterior treatment and sealing reduce them.
Should I vacuum or crush them?
Avoid crushing — it releases the odor. Vacuuming is better, and sealing entry points prevents the problem long term.
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