Brown marmorated stink bugs move into houses in late summer and fall to spend the winter. This guide shows you how to identify them, remove the ones already inside and seal the gaps they use to get in.
By The Homefield Journal Editors Reviewed
The stink bug most likely to show up inside your house is the brown marmorated stink bug, an invasive insect native to Asia. The EPA describes the adult as shield shaped with brown mottling and 14 to 17 millimeters long, roughly the size of a U.S. dime. The UC Statewide IPM Program puts the adult at about 5/8 inch long and lists the features that separate it from native look-alikes: two white bands on each antenna, a smooth edge on the shoulders, marbled brown legs with faint white bands and a banded edge along the abdomen that shows beside the wings.
According to UC IPM, the species has been found in at least 40 states, and the EPA reports the highest concentrations in the mid-Atlantic region. If you are unsure what you have found, the EPA suggests contacting your state department of agriculture, a university diagnostic laboratory or your Cooperative Extension office.
Adult brown marmorated stink bugs spend the winter in a resting state, and in late summer and early fall they gather on warm, sunny walls while they look for a sheltered place. UC IPM notes that their habit of wintering in narrow cracks and under loose bark has helped them adapt to homes. The EPA says that where the insect is established, hundreds or even thousands can enter a single structure.
Once inside, they tuck into cracks under or behind baseboards, around window and door trim and around ceiling exhaust fans and light fixtures, and UC IPM notes they prefer high, cool spots. The EPA adds bookcases, the space under beds and sofas, and attics.
The EPA, UC IPM and University of Maryland Extension all describe the brown marmorated stink bug as harmless to people, pets and houses. It does not bite or sting, it does not spread disease, it does not eat or bore into wood and it does not reproduce indoors. Stink bugs release their odor when disturbed or crushed, and Maryland Extension says the smell goes away quickly.
Because the odor is released when a stink bug is crushed, the extension methods collect the bugs whole. These steps follow University of Maryland Extension and UC IPM guidance:
Stink bugs are drawn to light, and UC IPM calls a homemade light trap the most effective and inexpensive way to catch the ones that have come indoors. Fill a foil roasting pan with some water and a few drops of dish soap, point a light into the pan and set it in a dark room. The bugs fly to the light, fall into the water and drown. The EPA describes the same kind of soapy water and light trap and notes that additional steps are needed for complete control.
The same attraction draws them toward your doors at night, so UC IPM recommends turning off lights you do not need and keeping exterior lights on away from the entrance when you come and go.
Maryland Extension calls mechanical exclusion the best way to keep stink bugs out of homes, and UC IPM describes sealing as the more effective and environmentally sound strategy. The job fits into the fall tasks on a seasonal home maintenance checklist, and these steps combine the EPA, UC IPM and Maryland Extension guidance:
Utah State University Extension also suggests avoiding host plants around buildings where possible, and UC IPM names tree-of-heaven, catalpa and redbud among the ornamental trees the bugs feed on.
UC IPM says indoor sprays are generally ineffective and not recommended. The EPA notes that aerosol and fogger insecticides labeled for stink bugs will kill the ones in a room, and more will keep emerging from cracks once the spray dries, so these products offer no long-term solution. Maryland Extension also warns against dusting wall voids or attics after the bugs are inside, because carpet beetles can feed on the dead stink bugs and then attack woolens and stored dry goods.
Spraying outside around entry points may deter stink bugs for a short time, and UC IPM notes the sprays break down rapidly, often within days. Maryland Extension generally does not recommend exterior insecticides for this pest because of their cost, their health and environmental risks and their uncertain results, and it says any application should be made in the fall just before the bugs gather, by a licensed pest control operator. For any product you apply yourself, follow every label direction. UC IPM notes that some products are available only to licensed applicators, and your Cooperative Extension office can tell you what applies in your state.
In spring the adults leave their winter hiding places and move to host plants, and UC IPM notes they feed for about 2 weeks before mating. Females lay eggs in clusters of 20 to 28 on leaves, and the EPA says the species produces one or two generations a year in cooler climates and up to five in warmer ones.
In the vegetable garden the bugs pierce fruit and seeds and leave pockmarked, pithy spots. UC IPM notes that a small damaged spot can be cut out without affecting eating quality, and it lists row covers, hand picking into soapy water and destroying egg masses on the undersides of leaves among the methods for larger populations. For other uninvited guests, see our guide to getting rid of gnats in the house and the rest of our cleaning and maintenance articles.
When to call a pro
Most stink bug problems are handled with a vacuum and a caulk gun, and a licensed pest control company or a contractor becomes useful when the entry points or the treatment are beyond safe reach.
The EPA, UC IPM and University of Maryland Extension all say brown marmorated stink bugs do not bite or sting people or pets, do not spread disease and do not damage the structure of a house. The EPA notes that some people may be sensitive to allergens the bugs give off.
Drop them into a container of water mixed with a teaspoon of liquid detergent or soap, where University of Maryland Extension says they cannot escape and will drown. UC IPM adds that live bugs sealed in a plastic bag die after 2 days in the freezer. Collecting them whole keeps the odor from being released.
They came in during late summer or fall to spend the winter and are hiding in cracks behind baseboards, around trim, near ceiling exhaust fans and lights, and in attics. UC IPM notes that adults do not reproduce indoors during winter and feed little, if at all, so the bugs you see are adults that got in before the cold.
The EPA and UC IPM both state that brown marmorated stink bugs do not reproduce inside homes. Females lay their eggs in clusters on the undersides of leaves of host plants after the adults move outdoors in spring.
Sources checked on November 9, 2026.
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