An OSU Extension fact sheet, as reported locally, says brown marmorated stink bugs are most often found in attics and upper stories rather than basements. They are harmless to people and pets but give off an odour when disturbed. In Columbus, control starts at the roof line and works down: find the entries, remove the bugs by vacuum and seal the route.
Key takeaways
- The OSU fact sheet places these stink bugs most often in attics and upper stories.
- They are described as harmless to people and pets, but they give off an odour when disturbed.
- Start the walk at the roof line and the eaves, not the basement.
- Remove bugs by vacuum, sealing the bag, rather than crushing them.
- Seal the vents, eaves and soffit joints before the cold months.
- This guide uses the fact sheet as reported, since the full sheet was not read for this site.
Why do stink bugs gather high in the house?
The reporting on the OSU fact sheet says they are most often found in attics and upper stories rather than basements. Warm, sheltered spaces under the roof are where the bugs settle, and they seek the same spots in the cold months.
An attic is warm in the autumn sun, sheltered from the weather and quiet. An insect looking for a sheltered place for the cold months finds an attic attractive, and the roof boards hold heat through the day. The bugs enter through the roof line and the eaves, and they settle along the boards and in the corners, where the temperature changes slowly.
The rooms below follow. A bug that enters at the top can move down through a wall void or a gap around a pipe, and it turns up in the closets and corners of the rooms just beneath the roof. For that reason, the walk for a stink bug problem starts at the top of the house.
What do the stink bugs do to a home?
According to the reporting, they are harmless to people and pets and give off an odour when disturbed. The odour is the main nuisance, and the number of bugs in a room is the second.
The odour is a defence the insect releases when it is disturbed, crushed or handled. It can cling to fabric and linger in a room, and a homeowner who crushes one may notice it for some time. The bugs do not bite or sting people, and the reporting does not describe a health risk from them.
A large number of bugs in one room is a nuisance even without an odour. The homeowner may find them on windows, lights and furniture. The safe way to deal with them is the vacuum, not the hand or the shoe.
Where do the entries sit on the outside of the house?
The entries are usually at the roof line: the eave where the roof meets the wall, the gable vent, the soffit joint and any roof penetration. A gap in one of those lets the bugs into the attic space.
From the ground, the technician checks each eave and gable for a gap, each vent for a torn or missing screen, and each soffit joint for a space that has opened. A ladder is used with care, and a high section that cannot be reached from the ground is listed as not checked.
The roof penetrations, such as a vent pipe or a flue, are checked for a collar or a seal that has come loose. A gap around a penetration is a route that is easy to miss from below and is worth a look on the outside walk.
How is the attic walk done?
Inside, the attic is walked on the boards with a light, looking for light and draughts at the gaps and for bugs in the corners. The attic is entered only when the boards are safe to walk on.
A beam of light visible through a gap at the eave, or a draught moving insulation near a vent, marks a route that the outside check may have missed. The technician marks each route on a plan and notes its position on the building.
The insulation is not pushed into a gap to hide it. A gap is sealed from the outside or from the inside where the material can be fixed, and the insulation is put back so it covers the boards as before.
How are the bugs removed and the route sealed?
The bugs are vacuumed, the bag is sealed and taken out of the house, and the entries are sealed with a material suited to each one. A torn vent screen is replaced at once.
A vacuum with a narrow nozzle reaches the corners of the attic and the closets below. The bag is sealed at once. The room is kept closed until the work is finished, so the bugs do not move to another room while the walk is under way.
Sealing uses a fitted screen on a vent, caulk or foam at a small joint and a metal cover for a larger opening. Each is chosen for the surface and its exposure to weather. Foam exposed to sun is covered, because it breaks down under ultraviolet light.
When should the work be done, and what follows?
The sealing is best finished before the autumn, when the bugs look for overwintering spots. A check after a heavy storm or a freeze, and again in the spring, looks for any gap that has opened.
A storm or a freeze can move the roof boards and open a gap at the eave, and a check after either is worth making. The report lists each check and its date, so the next season starts from a known condition.
A homeowner can do a simple monthly check of the attic from the hatch in the cool season, looking for new bugs, droppings or a draught near a vent. A dated note of each check is the most useful record for the next visit.
Why does the attic-first walk suit a Columbus house?
Most Columbus houses with an attic have a roof line that is easy to walk from the ground, and the attic is reached by a single hatch. Starting at the top means the entries are found before the bugs move down the house.
An attic-first walk saves time on the house. The outside check at the eaves and gables is done first, then the attic from the hatch, and then the rooms below. The order follows the way the insects move, which is from the roof downward through the wall voids.
Where a house has no usable attic, the walk starts at the top floor and the eaves instead. The report states which route was used and why.
What should be done about bugs found on an upstairs window?
Bugs on an upstairs window are usually on the way in or out. The window frame is checked for a gap, the screen is checked and the bugs are removed with the vacuum.
A bug on the glass is a sign that the window is a route. The frame is checked at each corner and the sill for a gap that lets light through. The bugs are vacuumed from the glass and the tracks, and the bag is sealed.
A window with a torn screen or a gap at the sill is repaired, and the repair is noted on the plan so the next season can check it.
How should a homeowner record the sightings?
Record each sighting with its date, its room and its position in the room. A dated list helps the technician place the activity in time and find the route.
A note such as the closet on the upper landing, early October, a few bugs on the shelf is much more useful than a general complaint. Over several weeks, the notes show whether the activity is rising, falling or moving to a new room.
Keep the notes with the house file, and bring them to the visit. The technician can then start the walk where the notes point.
What does a homeowner do if the bugs come back in the spring?
Spring activity usually means a gap that was missed in the autumn or a window or door left open on a warm day. The homeowner notes the date and room, and the technician checks the route before any new step.
A few bugs in an upstairs room in April are most often bugs that spent the winter in the house and came out when it warmed. Vacuum them, note where they were and keep the route in mind for the autumn sealing.
A steady number in the same room through the spring points to a gap still open. The technician checks that spot on the next visit, and the sealing list is updated for the coming autumn.
Frequently asked questions
Are the stink bugs dangerous to my family or my pets?
According to the reporting on the OSU fact sheet, they are harmless to people and pets. Their main effect is the odour they give off when disturbed.
Why do they only show up in the upper floors?
The reporting places them most often in attics and upper stories, where the warm and sheltered spaces are. A basement is cooler and less attractive to them, though a bug can move down through a wall.
Can I spray the attic myself?
This guide does not recommend it as a first step. The sealing and the vacuum come first, and a residual is considered only if the bugs keep coming after the gaps are closed. Follow the label if a product is used.
Why does the guide rely on a news report?
The full OSU fact sheet was not read for this site. The guide uses only what the reporting gives, and it does not add a count or a seasonal peak for Columbus.
Is an attic fan a route for the bugs?
A fan that is not fitted with a screen can be a route. The walk checks the fan housing and its screen, and recommends a fitted screen where one is missing.
Do they come back every year?
They can, because a warm house and open gaps draw them in again. The sealing list and the yearly attic check are what reduce the number over time. A single season’s clearance does not close the route on its own.
Sources
This guide is general information for Franklin County homeowners, not a substitute for an on-site inspection. Prices are estimates. See our disclaimer.