Silverfish, Earwigs, and Centipedes in Your Montreal Basement — Are They a Problem?
Your basement has bugs. Strange-looking ones. Fast ones. Ones with too many legs.
Before you burn the house down, let me tell you something that might change how you feel about at least one of them.
House Centipede (Scutigera coleoptrata)
The one with a hundred legs that runs across your wall at midnight like something from a horror movie.
The truth: House centipedes are beneficial predators. They eat cockroaches, bed bugs, silverfish, spiders, ants, and other insects. A house centipede in your basement is a free exterminator. Should you worry? If you see the occasional centipede — no. They are solitary, non-aggressive, and their bite (rare) is less painful than a bee sting. They are a sign that their prey exists in your home, but their presence is actually keeping other populations in check. When to worry: If you are seeing centipedes regularly (multiple per week), it means their food source — other insects — is abundant. The centipedes are not the problem. The insect population they are feeding on is the problem. Address the prey (cockroaches, silverfish, spiders) and centipede numbers drop naturally. Control: Reduce basement humidity below 60% (dehumidifier). Seal cracks. Remove clutter. The centipedes will decrease as their habitat becomes less hospitable.Silverfish (Lepisma saccharina)
Small, silver-grey, teardrop-shaped, with three tail filaments. They move in a fish-like swimming motion — hence the name. You find them in bathrooms, basements, and around books and papers.
The truth: Silverfish are a nuisance pest. They eat starchy materials — paper, book bindings, wallpaper paste, cardboard, cotton fabrics, and some dry foods (flour, cereal). They do not bite, sting, or transmit disease. Should you worry? Mildly. A few silverfish are common in Montreal basements — the humidity supports them. But large populations can damage stored books, documents, photos, and textiles over time. They are also an indicator of high humidity. When to worry: If you find silverfish in upper floors (bedroom, living room), the humidity problem is building-wide, not just the basement. If you find damage to stored documents, photos, or clothing, the population is significant.Control:
- Dehumidifier in the basement — keep humidity below 55%
- Store paper goods, photos, and textbooks in sealed plastic bins, not cardboard boxes
- Fix any water leaks or condensation issues
- Caulk cracks along baseboards and around pipes
- Sticky traps in corners to monitor population
- Diatomaceous earth dusted lightly along baseboards and in cracks (desiccates their exoskeleton)
Earwigs (Forficula auricularia)
Brown, elongated, with distinctive pincers at the tail end. They look menacing. They are not.
The truth: Earwigs are primarily outdoor insects that wander indoors accidentally. They do not crawl into ears (that is a myth dating back to medieval Europe). Their pincers can pinch if handled, but the pinch is too weak to break skin. Should you worry? Only if you are seeing them regularly indoors. A few per summer is normal — they come in through door gaps, window frames, and where the foundation meets the ground. When to worry: Earwigs in large numbers indoors suggest ground-level entry points that also allow other pests (ants, spiders, mice). Fixing the entry points solves the earwig problem and prevents future issues with more problematic pests.Control:
- Reduce outdoor mulch depth near the foundation — earwigs breed in moist organic material. Keep mulch below 5cm and at least 30cm from the foundation wall.
- Remove debris (leaf piles, woodpiles) from along the house
- Install door sweeps on ground-level doors
- Replace white exterior lights with yellow bulbs (earwigs are attracted to light at night)
- If indoor sightings are frequent, a perimeter spray treatment by a professional handles it quickly
The Common Thread: Moisture
All three of these insects thrive in humid environments. If your Montreal basement has all three, the message is clear: you have a moisture problem.
Investing in a dehumidifier, fixing water infiltration, and improving basement ventilation will reduce populations of all three — plus mold, musty odors, and the general unpleasantness of a damp basement.
A $300 dehumidifier does more for basement pest control than $300 worth of spray treatments.
Frequently Asked Questions
Are any of these insects dangerous in Montreal?
No. None of the three — house centipedes, silverfish, or earwigs — are dangerous to humans in Montreal. They do not transmit diseases, and their bites or pinches (rare) are less impactful than a mosquito bite.Should I call an exterminator for these bugs?
For occasional sightings — no. Fix the moisture, seal entry points, and reduce clutter. Call a professional if you are seeing large numbers regularly (multiple per day), which indicates a significant moisture problem or a large insect population that needs broader treatment.Got a pest problem?
Extermination DMP serves Montreal, the South Shore, Laval & the West Island — 24/7.
Call 438-879-5706