Found a Shield-Shaped Bug on Your Curtains in Winter? It’s Likely a Brown Marmorated Stink Bug—Here’s What to Know

Sofia MarinSeptember 4, 2026

You’re folding laundry or drawing the curtains—and suddenly, you spot it: a slow-moving, shield-shaped insect with a speckled brown back, crawling where it shouldn’t be.

And it’s winter.

Don’t panic. You’ve likely encountered a brown marmorated stink bug (BMSB)—a common seasonal invader that seeks shelter indoors when temperatures drop. The good news? It won’t bite, sting, or infest your home like termites or ants. But it can be a nuisance. Here’s what you need to know.

🔍 How to Identify a Brown Marmorated Stink Bug

Shape: Distinctive shield-shaped body (~⅝ inch long)

Color: Mottled brown with grayish-white speckles

Markings:

Alternating black and white bands on antennae

White bands on the edges of the abdomen (visible from above)

Behavior: Moves slowly, clumsy flier, emits a pungent odor when crushed (like cilantro or burnt rubber)

🐛 Not to be confused with:

Boxelder bugs (red/orange markings)

Kudzu bugs (greenish, rounder)

Beneficial stink bugs (bright green, garden helpers)

❓ Will It Bite or Infest My Home?