14-17 mm – Marbled brown
Insect – Low risk
Brown bug
The brown marmorated stink bug (Halyomorpha halys) is an invasive species native to Asia that arrived in Quebec in the 2010s. It enters homes en masse in autumn to overwinter in walls, attics and closets. Although it doesn’t bite and doesn’t transmit disease, its foul odor when crushed and its presence in large numbers make it highly undesirable.
§1Distinctive features
How to identify it
14 to 17 mm shield-shaped (pentagonal) bug. Marbled brown resembling bark. Antennae with alternating light and dark stripes. Emits a very unpleasant odor of burnt coriander when threatened.
§2Habitat
Where to find it
It overwinters in dwellings (walls, attics, false ceilings), farm buildings and forests. In summer, it lives in gardens and crops, where it feeds on fruit and vegetables.
§3Reproduction
Lifecycle
Without intervention, an infestation can double in size in just a few weeks.
§4What to look out for
Signs of infestation
- Sudden appearance of numerous bedbugs on exterior walls in autumn
- Bugs in window frames, cracks and sills
- Characteristic smell of burnt coriander if crushed
- Springtime outbreak of window bugs
§5Why act fast
Risks
- No direct health risk (does not bite, does not transmit disease)
- Very unpleasant smell if crushed
- Massive, psychologically exhausting presence
- Damage to crops and gardens in summer
§6Prevention
How to avoid it
- Caulk all cracks, windows and doors before fall
- Install mosquito nets in good condition
- Use caulking on all frames
- Professional peripheral treatment in August-September
§7Pro method
How MW works
Inspection
Home location and assessment.
Preparation
Customized plan – pre-intervention measurements.
Treatment
Locate main and satellite nests, treat with non-repellent baits.
Follow-up
Inspection visit – written guarantee.
§8We answer you
Frequently asked questions
Can they be crushed?
Better to vacuum them up or put them in soapy water – crushing them releases a very unpleasant odor.
Are they dangerous?
No, they don’t bite and they don’t transmit disease. Their only drawback is their invasive presence and smell.
How do you keep them out?
Careful caulking of all openings before September is the best prevention. Professional perimeter treatment can complete the picture./
React quickly, sleep well.
The longer the infestation lasts, the more expensive it becomes.