It is October and a large brown bug is crawling across the living room ceiling, or buzzing loudly against a lamp. The first question is nearly always: “Is that a bed bug?” It isn’t. The bugs that come into Quebec homes in the fall are looking for a place to spend the winter. Still, it is worth knowing which one you have, because one of them is closely watched by Quebec’s agriculture ministry.
First: it is not a bed bug
| Fall invaders | Bed bug | |
|---|---|---|
| Size | 12 to 20 mm | 5 to 7 mm, like an apple seed |
| Wings | Yes, they fly | No, it can’t fly |
| Shape | Shield-shaped or long | Oval and very flat |
| Where you see it | Windows, ceilings, light fixtures, in daylight | Mattress, box spring, headboard, mostly at night |
| Bites people | No | Yes |
If what you found is small and wingless and you wake up with bites, read our article on bed bug bites and our bed bug profile instead.
The three bugs you will see in the fall
Western conifer seed bug: the most common
Fifteen to 20 mm long and reddish brown, it has long legs and one unmistakable detail: flattened hind legs, shaped like a small leaf. There is a thin white zigzag across its back. In flight it buzzes loudly and shows an orange abdomen banded with black. Handled, it gives off a smell of pine resin or green apple.
Originally from the western United States, it has spread all the way to Eastern Canada. It feeds on the seeds of pines and other conifers, so homes surrounded by evergreens get more of them. Espace pour la vie notes that it looks for shelter as the cold sets in, which brings it near houses and sometimes inside. It is harmless to you and to the house.
Brown marmorated stink bug: the one worth reporting
Twelve to 17 mm long, shield-shaped, a mottled greyish brown. To identify it, check two places:
- the antennae: pale rings on the last segments;
- the edge of the abdomen, sticking out from under the wings: alternating light and dark bands.
Native to Asia, the brown marmorated stink bug (Halyomorpha halys) was first found in Quebec in 2014, and adults and young have been caught every year on the island of Montreal since 2016, according to Quebec’s agriculture ministry, MAPAQ (in French). Indoors it is harmless: the City of Montreal (in French) states it poses no danger to human or animal health. The problem is agricultural: it damages orchards, berries and vegetables. That is why it is monitored, and why a sighting outside Montreal is of interest to specialists.
Like the Asian lady beetle, it overwinters in groups inside buildings, looking for those sites as the days shorten in September and October.
Native stink bugs
Quebecers often call any shield-shaped bug a “punaise des bois”. Our native species, brown or green, look like the marmorated stink bug but lack the pale-ringed antennae and the contrasting bands along the abdomen. Some have pointed “shoulders”; others have a bark-like texture. They come indoors far less often and in small numbers.
What they do in your home
None of these bugs breeds indoors, bites people, or eats wood or food. They spend the winter dormant in walls, attics and window frames and leave in the spring. The ones you see in your rooms are drawn by warmth and light.
The downsides: the smell when crushed (hence “stink bug”), stains on fabric, and the conifer seed bug’s noisy flight. As with lady beetles, dozens of dead insects in a wall attract carpet beetles.
Removing them
- A vacuum with a nylon stocking slipped into the hose, then the stocking thrown out in a sealed bag. Without it, the smell stays in your vacuum.
- A jar of soapy water: hold it under the bug and nudge it; it drops when disturbed.
- No crushing, especially on curtains and bedding.
- No insecticide indoors: it won’t reach the ones in the walls and leaves residue where you live.
Keeping them out: August and September
The only lasting fix is exclusion, done before they arrive. It is the same work as for Asian lady beetles and cluster flies:
- caulk around windows, doors and wall air conditioners;
- seal the joint between siding and soffits, and cracks in the foundation;
- put fine mesh over attic, bathroom and dryer vents;
- repair screens, including basement windows;
- seal cable and pipe entries.
A perimeter exterior treatment can cut the number of insects on the walls, provided the product’s label covers the insect and it goes on before they settle in for the winter. It complements sealing; it doesn’t replace it.
When to call
- You find dozens in your rooms every day.
- You can’t tell where they get in.
- You think it might be a bed bug: an inspection settles the question quickly.
For an assessment, contact us or call 514-638-8705, 24 hours a day. The estimate is free.
Not sure what you found? Our guide to bugs in the house in Quebec helps you identify it by where and when you see it.
Frequently asked questions
Is the brown marmorated stink bug dangerous?
No. It doesn’t bite or spread disease. It is monitored because it damages crops, not because it threatens people.
Why do I see them in the middle of winter?
Heating or a mild day wakes up the ones overwintering near a warm surface. They head toward the light and end up in the windows.
Will they be back next year?
Probably, if the openings stay the same. Homes invaded one year often are the next. Sealing at the end of summer is what makes the difference.