Stink bugs

What stink bugs look like

Stink bugs belong to the family Pentatomidae, and the name comes from their shape as much as their smell. The body is a broad shield, roughly 12 mm to 17 mm long, widest at the shoulders and tapering to a point at the back. The brown marmorated stink bug, the one most often found in Ontario buildings, is mottled brown and grey with alternating light and dark bands along the outer edge of the abdomen and two pale bands on each antenna. Native green stink bugs are bright grass green and rounder. All of them have piercing mouthparts folded under the head for feeding on plants, and scent glands on the underside that release a strong odour when the insect is crushed, squashed or handled roughly.

Signs you have stink bugs

• Insects on sunny walls. Numbers of shield shaped bugs basking on south and west facing siding, brick and window trim in late summer and early autumn.
• Slow fliers indoors. A clumsy, buzzing flight across a room, often ending at a lamp, a curtain or a window.
• Bugs at openings. Insects working into gaps around window frames, vents, soffits, chimney chases and behind shutters.
• A sharp smell. A pungent, coriander like odour after one is stepped on, vacuumed or swatted.
• Winter appearances. Single bugs walking across a ceiling or floor on mild days, well after the outdoor season has ended.
• Garden damage. Dimpled, corky or misshapen tomatoes, peppers, beans and tree fruit where the bugs have fed.

Most people notice them twice: in the autumn rush indoors and again in spring when they leave.

Why stink bugs show up around Ottawa and Toronto properties

The brown marmorated stink bug is an introduced species from Asia that has spread through southern Ontario and into the Ottawa region. It feeds on a very wide range of plants, so gardens, orchards, hedgerows, ornamental trees and field crops all support it through the summer. In late August and September, shortening days drive the adults to look for a sheltered place to spend the winter. In nature that would be under bark or in rock crevices. A heated building on a sunny lot is better, so they land on warm walls in the afternoon and crawl into any gap they find. Once inside a wall void or attic they stay dormant until warmth, either a mild spell or indoor heating, brings them out.

Are stink bugs dangerous?

To people, no, and it is worth saying plainly. Stink bugs do not bite or sting, they do not carry disease, they do not feed on people or pets, and they will not chew wood, wiring, fabric or stored food. They do not breed inside buildings either, so the ones indoors in January came in last autumn rather than hatching in your wall. The real problems are the smell and the numbers. Crushing them releases an odour that lingers on skin, cloth and vacuum bags, and a large overwintering group can produce a steady trickle of insects indoors all winter. Outdoors they are a genuine agricultural and garden pest, damaging fruit and vegetables by feeding on them. Treat them as a nuisance rather than a hazard.

How to keep stink bugs away

• Seal gaps around window and door frames, utility penetrations, hose bibs and siding joints before the end of summer.
• Screen attic vents, soffit openings, roof vents and chimney chases with fine mesh that is fixed at the edges.
• Fit or repair door sweeps and weatherstripping, particularly on garage doors and basement entries.
• Vacuum the ones you find rather than crushing them, then empty the canister or bag outside straight away.
• Reduce exterior lighting on autumn evenings and keep window coverings drawn so lit glass draws fewer bugs to the wall.
• Keep host plants and heavy vegetation trimmed back from the walls, especially on the sunny side of the building.

Exclusion in late summer beats any attempt to chase them indoors in December.

How GO! Pest Control handles stink bugs

• Inspection. We identify the species and find the entry points and sunny gathering walls, checking soffits, vents, frames, siding laps and the attic where access allows.
• Treatment. We apply licensed exterior treatments to walls and entry areas timed to the autumn movement, when they do the most good.
• Proofing. We identify and can close the gaps, screen the vents and deal with the openings that let overwintering bugs into wall voids and attics.
• Follow-up. We check the result and return if bugs keep emerging indoors, since dormant insects can appear for weeks.
• Advice. We explain the seasonal pattern so you know what to expect in spring and how to prepare for next autumn.

We are licensed, insured and bonded, and we work in homes, apartments, condos and businesses across the Toronto GTA, Ottawa and Hamilton.

Common questions about stink bugs