BMSB in BC: current status (2026)
Brown marmorated stink bugs were first confirmed in Canada in Ontario in 2010 and were detected in the Lower Mainland of BC in 2015–2016. By 2026, populations are established in Surrey, Langley, Abbotsford, Chilliwack, and the Okanagan. They continue to spread northward and westward as populations build. The BC Ministry of Agriculture monitors distribution annually. For homeowners, the relevant facts: BMSB is present in Metro Vancouver and surrounding communities. Populations are most dense in areas with agricultural land and fruit orchards — Surrey, Langley, Abbotsford, and the Fraser Valley — because these provide ideal feeding habitat. Urban Vancouver and North Shore properties see lighter pressure currently but this is changing as populations expand. BMSB is not currently considered eradicated or containable in BC — it is established and spreading. Homeowners in affected areas should expect it as a recurring autumn event for the foreseeable future.
| Species | Size | Key features | Odour when disturbed | Concern level |
|---|---|---|---|---|
| Brown marmorated stink bug (H. halys) | 14–17 mm | Mottled brown, banded antennae and abdomen edge, smooth shoulder | Strong, unpleasant — 'cilantro/coriander' smell | High — agricultural pest, autumn home invader |
| Green stink bug (Chinavia hilaris) | 13–15 mm | Bright green, smooth edge | Moderate odour | Low — native, minor crop pest |
| Rough stink bug (Brochymena) | 13–17 mm | Dark grey-brown, rough texture, toothed shoulder | Mild | Low — native species, not a home invader |
| Western conifer seed bug (Leptoglossus) | 16–20 mm | Brown, leaf-like hind tibiae, pinched waist | Mild piney odour | Low — autumn home invader, not BMSB |
Why BMSB is a more serious concern than other fall invaders
Most fall-overwintering home invaders (cluster flies, boxelder bugs, Asian lady beetles) are nuisances. BMSB has additional significance: 1. Agricultural impact: BMSB is a piercing-sucking feeder that damages apples, peaches, plums, pears, cherries, grapes, and vegetables by injecting enzymes that cause fruit tissue to become necrotic and unsaleable. In the Okanagan and Fraser Valley, it's an emerging serious pest. For Metro Vancouver residents with backyard orchards or market gardens, monitoring and exclusion netting are increasingly relevant. 2. Odour severity: the defensive odour produced when a BMSB is disturbed, crushed, or trapped indoors is significantly stronger than that of other fall invaders. It persists in fabric and has been described as 'musty cilantro' or 'skunky herbs.' Crushing indoor BMSB is strongly inadvisable — capture and release or vacuum (with care) instead. 3. Population trajectory: unlike native fall invaders with stable populations, BMSB populations are expanding in BC. The scale of autumn home-invasion events is likely to increase in the 2026–2030 window as populations establish more densely.
BMSB home exclusion protocol
Identical foundation to cluster fly and boxelder bug exclusion — the September sealing window applies to all three fall-overwintering species simultaneously.
- 1Building envelope inspection — AugustInspect the full exterior for gaps: window frame perimeters, door frames, utility penetrations, soffit-fascia junctions, weep holes in brick veneer, vents, and any gap in exterior cladding. BMSB enter through gaps as small as 5–7 mm.
- 2Seal all identified gaps — before SeptemberCaulk window and door frame perimeters with flexible exterior caulk. Replace worn door sweeps. Seal utility penetrations. Install fine-mesh (0.6 mm) overlays on existing window screens if needed. BMSB can push through standard coarse-mesh window screens. Complete sealing before mid-September.
- 3Exterior residual treatment on south and west walls — SeptemberApply a pyrethroid residual spray to south and west-facing exterior walls and around all entry point areas in early September. BMSB can be harder to kill with pyrethroids than native species; higher-label-rate applications or kaolin clay (for agricultural areas) may be needed.
- 4For BMSB that enter: vacuum, do not crushThe most important indoor rule for BMSB: do not crush them. Use a vacuum with a bag (not a canister) to capture live bugs. Empty the vacuum bag outdoors immediately. Alternatively, capture in a container with soapy water — BMSB cannot escape soapy water. Never swat or crush inside the home.
- 5Agricultural areas: tree netting and trunk treatmentFor properties with tree fruit or soft fruit crops, exclusion netting over individual trees is increasingly used in the Okanagan and Fraser Valley. Contact BC Ministry of Agriculture for current BMSB management guidance for registered crops.