Stink Bugs in Delaware: How to Spot Them and Keep Them Out

What they look likeSignsAre they dangerous?How we treat themPreventionFAQ

What do they look like?

The brown marmorated stink bug is an invasive insect from Asia. It was first found in the US in Allentown, Pennsylvania, in 1998, after arriving in shipping materials. University of Delaware entomologist Brian Kunkel has called this region the epicenter of the stink bug outbreak. You'll usually notice them in fall, gathering on houses, decks, and garages as the nights get cooler.

Signs you have them

• Stink bugs gathering on siding, decks, and garages as fall nights cool
• Stink bugs inside on walls, windows, and lights in autumn
• Gaps around windows, torn screens, or open attic vents where they get in

Are they dangerous?

Stink bugs are mainly a nuisance. The problem is numbers. Most indoor trouble comes in autumn, when they gather on houses and find their way inside. Once they're in, UD's Brian Kunkel says insecticides do little, so the work has to happen before they get in.

When are they active?

Adults reproduce in June, and the young become adults by late August. They gather on houses as nights cool, and most indoor trouble comes in autumn.

How Wolfe treats them

Exclusion comes first. UD's advice is to seal up every opening, and we follow it. We look for gaps around windows, torn screens, open attic vents, and rotten wood, and we help you get the house sealed before fall. Spraying inside does little once they're in, so we focus on keeping them out. Call us at (302) 697-8969 before the fall rush.

How to keep them out

• Caulk around windows.
• Repair torn screens.
• Screen attic vents.
• Replace rotten wood.
• Leave spiders alone outside. They eat stink bugs.

Common questions

Sources: UDaily: Stink bugs

Last reviewed October 2026 by Wolfe Pest Control.