How to Get Rid of Stink Bugs in Your House

How do you get rid of stink bugs in your house?

There are two separate jobs and they work on different timescales. Removing the bugs already indoors is mechanical: vacuum them up and throw the bag out. Keeping the next wave out is exclusion, sealing the gaps they use before the autumn flight begins. Insecticide indoors does neither job well, and every extension service below advises against it once the insects are already in the building.

The reason exclusion matters more than killing is that a stink bug indoors is a trespasser, not a resident. It is not feeding, not breeding and not damaging anything. Penn State Extension states plainly that the brown marmorated stink bug will not reproduce inside structures or cause damage. Remove the ones you can see and seal the building, and the problem ends with the season.

What does a brown marmorated stink bug look like?

Ohio State University Extension describes the adult as about 5/8 inch long and 3/8 inch wide, roughly the size of a human thumbnail, shield shaped, in mottled shades of brown and gray. Penn State measures adults at about 17 mm, or 0.66 inch, and notes patches of coppery or bluish metallic punctures on the head and the plate behind it.

Three marks separate it from the native stink bugs it gets confused with.

• Banded antennae. Ohio State points to alternating dark and light bands on the last two antennal segments. Clemson Cooperative Extension describes them as distinct black and white bands.
• Banded abdomen edge. Ohio State notes that the exposed side edges of the abdomen carry alternating light and dark banding, more prominent than in other stink bug species.
• Rounded shoulders. Clemson describes rounded edges on the shoulders behind the head.

Clemson acknowledges that several native stink bugs are mistaken for this one and recommends a county extension office for a firm identification. Our guide to identifying common house pests covers the other insects that turn up indoors in the same weeks.

Do stink bugs bite or cause harm?

No. Ohio State University Extension states that these stink bugs do not bite people or pets. They do not sting, they do not carry disease indoors, and they do not chew wood, fabric or stored food. The nuisance is behavioral: they fly clumsily around rooms, bump into walls and land on lamps and screens.

There is one genuine health caveat, and it is about the odor rather than contact. Penn State reports that the defensive chemicals can act as an aeroallergen and produce allergic reactions, specifically rhinitis or conjunctivitis, in people sensitive to the smell, and notes that people sensitive to cockroach and lady beetle odors may be more affected. Penn State also reports that crushing one against exposed skin can produce dermatitis at the point of contact, while adding that research is limited and it appears to affect a small share of the population. Anyone whose reaction is severe or persistent should see a doctor rather than treat this page as a diagnosis.

When and why do they come indoors?

They are looking for somewhere to spend the winter, and the flight is predictable. Ohio State reports that adults begin flying to overwintering sites in early September, with peak flight activity in late September or early October. Penn State gives the same window, September through October, and notes they are drawn to the outside of houses on warm autumn days. Clemson adds that they congregate on exterior walls before they find a way in.

Ohio State notes they are more likely to end up in attics and upper stories than in basements, and that they enter around windows, chimneys and window-mounted air conditioners. Penn State lists wall voids and attics as the spaces they settle in, and says they later emerge indoors from cracks behind baseboards, around window and door trim, and around ceiling fans and light fixtures. Ohio State puts spring emergence at usually early May.

Clemson adds a detail that explains why wooded lots see more of them. Their natural overwintering sites are dead standing trees with thick bark, such as oaks and locusts, and they avoid downed timber and leaf litter, which hold too much moisture. A house is a large, dry, warm substitute. The seasonal pest calendar sets this alongside the other autumn arrivals.

How do you remove the ones already inside?

Vacuum them. Ohio State says live and dead bugs can be removed with a vacuum cleaner or shop vacuum, and that the bag should be removed and discarded promptly. Clemson says the same and specifies disposing of the bag in a sealed container. Penn State confirms vacuuming works for both live and dead insects but warns the machine may hold the smell for a while, which is a good argument for using a shop vacuum rather than the household one.

Ohio State offers a quieter method that uses their attraction to light: turn on a single light in an otherwise dark room and collect the bugs in a jar or bottle as they come to it. Dispose of them outside or sealed in the trash.

Avoid crushing them. Penn State attributes the smell to scent glands on the upper surface of the abdomen and the underside of the thorax, and crushing is also the route to the skin reaction described above.

Why should you not spray insecticide indoors?

Because it does not solve the problem and it creates a second one. Ohio State states that insecticides should not be used inside houses after the insects have gained access, because it will not stop further invasions and exposure of people and pets to pesticides should be avoided.

Penn State is more specific about the second problem. Dust treatments into wall voids may kill hundreds of bugs, but carpet beetles then feed on the dead insects and go on to attack woolens, stored dry goods and other natural materials in the house. Penn State also rates aerosol foggers as a poor long-term answer, since more bugs emerge once the room is aired, and says sprays directed into cracks and crevices are not a viable or recommended treatment.

How do you keep them out next fall?

Seal the building before the September flight. Penn State calls mechanical exclusion the best method and names the places to seal: cracks around windows, doors, siding and utility pipes, behind chimneys, and under the wood fascia, using a good quality silicone or silicone-latex caulk. Damaged door and window screens should be repaired or replaced.

Clemson adds weatherstripping around doors, windows and garages, screening that fits tightly in the frame, screening on eaves, soffits and attic entry points, the gaps where plumbing and telephone, cable and electrical lines enter, and a chimney damper that closes tightly. Ohio State adds removing window-mounted air conditioners for the winter and sealing around exhaust fans and ceiling fixtures. The pest prevention checklist covers the same ground for the rest of the year.

When is it worth calling a pest control company?

Two situations. The first is a building you cannot seal yourself, where Penn State notes that a licensed pest control operator can apply an exterior treatment in the fall just before the bugs congregate, while cautioning that sunlight breaks these materials down and the effect may not last beyond a week or so. The second is sheer volume: Clemson suggests calling a professional when the numbers are past what a vacuum can handle.

PestChief passes your ZIP code and your pest to one independent local pest control company that covers your address and handles stink bugs, and that company contacts you directly to discuss the work. PestChief performs no treatments and charges homeowners nothing. Bear in mind that this insect is also a serious agricultural pest of fruit and vegetable crops, so in farming areas the pressure on a house is partly coming from the surrounding land rather than the yard.