Brown marmorated stink bugs were introduced to North America from Asia in the late 1990s. UMass Extension says that, beyond farms, they became a nuisance by overwintering in homes, office buildings, sheds and warehouses. Seal the entries before the cold, walk the sheltered spaces in order, and expect a second check in the spring.
Key takeaways
- UMass Extension names homes, office buildings, sheds and warehouses as overwintering sites.
- The walk starts at the roof line and the attic, which are the sheltered upper spaces.
- Sealing the entries before the cold is the first step, and the walk finds the entries.
- A shed, a garage or a warehouse on the lot is walked as a building of its own.
- The sources here give no local count, so this guide does not claim one.
- A spring check finds the openings the winter has widened.
Where the insect came from
UMass Extension says brown marmorated stink bugs were introduced to North America from Asia in the late 1990s. They began as a farm pest, and the account on this site follows that history.
The insect is a stink bug that feeds on plants, and its arrival in North America is the starting point of the UMass account this site uses. The Extension material describes its spread from the first sightings and the way it came to be a problem beyond the fields.
A reader who wants the detail of its biology should go to the UMass Extension pages directly. This guide uses only the points the Extension material states about the insect and its movement into buildings.
Why they move indoors to overwinter
UMass says that, beyond farms, brown marmorated stink bugs became a nuisance by overwintering in homes, office buildings, sheds and warehouses. Those sheltered buildings are where they spend the cold months.
When the weather cools, the insects look for shelter. The sources name homes, office buildings, sheds and warehouses as the places where they settle for the winter. A house is therefore one of several buildings the insect can use, and a Massachusetts home visit covers the same range of spaces.
The reason a homeowner sees them indoors in autumn is the overwintering pattern, not the state of the house. The walk is planned around that pattern, and it looks for the routes in and the spaces where the insects gather.
A seasonal calendar for the house
The useful calendar has four parts: the walk before the cold, the sealing in the weeks before the first hard frost, the autumn sightings, and the spring check after the thaw. Each part is set by the overwintering pattern rather than by a date.
In the warmer months the insects are outside, and the walk is not needed. In the weeks before the cold, when the outside work is still practical, the roof line, the frames and the vents are walked and sealed. Through the cooler months the homeowner notes any sightings in the upper rooms.
After the thaw the spring check looks for openings the winter has widened. The calendar is a method and not a set of local dates, because the sources here do not give a Massachusetts date range for the stages.
What a sign inside the house looks like
Signs inside the house are insects in the upper rooms, in windows, on walls and in the spaces near the attic. A homeowner who notes the room and date gives the technician the start of the walk.
A sign can be a single insect on a window, several on a wall near the ceiling, or a group in a corner of an upper room. The room and the date are the most useful notes, because the walk begins where the insects were seen.
A sign on a lower floor, or in a single room with no route to the attic, is still worth recording. The walk then follows the route the insects are likely to have taken, and the list shows whether an entry links the room to the upper spaces.
The sealing order for a house
Seal in the order the walk finds the entries: roof line and eaves first, then the frames, the cable and pipe openings, the foundation line and the cellar. The order keeps the list complete and the next check simple.
The roof line and the eaves are the first entries, because the sheltered upper spaces are the route in from outside. The vents, the gables and the soffit joints are checked and sealed in that stage.
Next come the window and door frames, then the openings for cables and pipes, then the foundation line and the cellar. A gap at the sill is listed by position, so the next check can find it quickly. Each stage has its own entries on the report.
Sheds, garages and the outbuilding
UMass names sheds among the overwintering sites, so each shed and garage is walked as a building of its own. A shared wall with the house is checked at the joint.
A shed has a door, vents and stored material, and each is checked. The stored items are moved where the walk needs to reach the corners, and they are put back where they were found.
A garage that shares a wall with the house has a joint that needs sealing from both sides where the owner allows it. The door seal is a separate entry on the list.
Warehouses and office buildings
Office buildings and warehouses are named among the overwintering sites in the UMass account. A commercial building is walked with its manager, with the loading doors, the service openings and the roof edge checked.
A workplace is not a house with more rooms. The spaces that need sealing are often the ones staff do not use, such as the top of a loading bay, the space above a suspended ceiling or a service duct. The walk asks the manager for access to those spaces.
The report for a workplace lists each building and its entries separately, so the owner can plan the sealing across the year.
What the sources do not say
The UMass material on this site gives the overwintering account and the history of the insect. It gives no local count for Leominster, no treatment efficacy figure and no date range for Massachusetts.
A reader may want a number of insects in a given town, or a guaranteed result from a given method. The sources do not give either. This guide does not supply them, and it does not claim that a particular method ends a problem.
What the sources do support is the pattern: the insects overwinter in buildings, and the entries are where the work begins. A visit is built on that pattern and on what the building shows.
Booking the visit and what to ask
Ask for the business name, the technician’s name and the licence details on request. Tell the technician the rooms, the dates and the outbuildings, and ask for a written list of the entries and the next step.
A visit is more useful when the homeowner has noted the sightings and the buildings on the lot. The technician needs the rooms and dates to start the walk, and the list of outbuildings to plan the time.
Ask for the licence details to be given on request. The Massachusetts Department of Agricultural Resources is named as the licensing body in a secondary study guide, and the details are to be verified on mass.gov.
Reading the UMass material for the house
The UMass material is most useful read as a description of where the insects go in autumn. It names the places and the pattern, and a homeowner can match the description to the building.
Read the material against the house on the call. Ask which rooms have the upper spaces, which walls face the outside, and which spaces connect the attic to the rest of the building. Those are the places the overwintering description points to.
The material does not say which room a specific insect will choose, and the walk does not guess. It follows the entries and the evidence, and it records what it finds.
The attic, the eaves and the roof line in practice
The attic and the eaves are where the walk spends most of its time on an autumn visit, because the sheltered upper spaces are named by the account as the overwintering places.
The eaves, the gables and the soffit vents are the first outside entries. A gap at a soffit board, a vent without a screen or a lifted corner of the roof line is marked and listed. The attic is then walked from the hatch, with a light, and any opening into the wall void is noted.
The walk does not stop at the first gap. A house with one open soffit often has others at the same height, and the walk checks each side for the same kind of entry before the list is closed.
What to expect after the first visit
After the first visit a homeowner should have a list of the entries, a note of what was sealed, and a plan for what remains. The spring check is part of the plan.
The list tells the homeowner which openings were closed on the day and which are waiting. A sighting after the visit is noted with its room and date, so that the next visit can follow it.
The spring check looks for openings the winter has widened and for any entry that was missed in the autumn walk. The sources here give no fixed number of visits, so the plan is set by the building and the list.
Reading the entries against the season
Each entry on the list has a season in which it matters most. Entries near the roof line matter most in the weeks before the cold, and entries at grade matter most after the thaw.
The sealing order on this site puts the upper entries first because they are the most sheltered, and the sources name the sheltered spaces as overwintering sites. A list read against the season tells the homeowner which entries are urgent and which can wait for the spring check.
A homeowner who has sealed the upper entries and not yet the lower ones is not finished. The list shows the lower entries as open, and the spring check is the time to close them if the autumn did not.
Why the list is written by position
An entry written as "left window" cannot be found again. An entry written as "north wall, second window from the corner, sill" can be, and that is why every entry is listed by position.
The position is the handle the next visit needs. A technician who knows that the second opening from the north corner was sealed can check it in seconds, and a technician who knows only that a window was sealed has to search.
Position is also the way the report links a sighting to an entry. A sighting in the upper bedroom and an entry on the north gable can be connected on the list, and the owner can see whether the two are likely to be the same route.
Frequently asked questions
Do brown marmorated stink bugs only live on farms?
No. UMass Extension says that, beyond farms, they became a nuisance by overwintering in homes, office buildings, sheds and warehouses.
When should the sealing be done?
In the weeks before the cold, when the outside work is practical. The sources give no Massachusetts date range, so the timing is set by the weather and the building.
Will sealing stop every insect?
The sources do not claim that. Sealing closes the entries the walk finds, and a spring check looks for openings that the winter has widened.
Sources
This guide is general information for Worcester County homeowners, not a substitute for an on-site inspection. Prices are estimates. See our disclaimer.