Insect · Low risk
Brown Marmorated Stink Bug
The brown marmorated stink bug (Halyomorpha halys) is an invasive species from Asia that arrived in Quebec in the 2010s. It moves into homes in large numbers in the fall to overwinter in walls, attics and closets. Although it does not bite and does not transmit disease, its foul smell when crushed and its sheer numbers make it very unwelcome.
14 to 17 mm · Marbled brown
§1Distinctive features
How to identify it
A shield-shaped (pentagonal) bug, 14 to 17 mm long. Marbled brown, like tree bark. Antennae with alternating light and dark bands. It gives off a very unpleasant smell, reminiscent of cilantro, when it feels threatened.
§2Habitat
Where to find it
It overwinters in homes (walls, attics, drop ceilings), farm buildings and forests. In summer, it lives in gardens and crops, where it feeds on fruit and vegetables.
§3Reproduction
Lifecycle
Without exclusion, the bugs come back every fall, often in greater numbers.
§4What to look out for
Signs of infestation
- Sudden appearance of many bugs on exterior walls in the fall
- Bugs in window frames, cracks and ledges
- Distinctive cilantro-like smell when crushed
- Mass movement of bugs toward the windows in spring
§5Why act fast
Risks
- No direct health risk (it does not bite or transmit disease)
- Very unpleasant smell when crushed
- Large numbers that wear you down
- Damage to crops and gardens in summer
§6Prevention
How to avoid it
- Seal all cracks, windows and doors before the fall
- Install window screens in good condition
- Use caulking on all frames
- Professional perimeter treatment in August and September
§7Pro method
How MW works
Inspection
Locating infested areas and assessment.
Preparation
Customized plan · steps to take before the visit.
Treatment
Sealing entry points, residual treatment of sunny walls before the bugs arrive, and vacuuming of those already inside.
Follow-up
Control visit · written guarantee offered depending on the treatment chosen.
§8Your questions answered
Frequently asked questions
Can I crush them?
Are they dangerous?
How do I keep them out?
The brown marmorated stink bug does not sting and does not breed indoors: it only looks for shelter for the winter, often by the hundreds in south-facing walls. Exclusion works better than insecticide. That is what our pest control program covers, in Sherbrooke as well as Granby, and near the orchards of Haut-Richelieu and Farnham.
React quickly, sleep well.
The longer the infestation lasts, the more expensive it becomes.