Earwigs in Ontario

Overview

Earwigs are the fast-moving, pincer-tailed insects that Ontario homeowners find under flowerpots, in damp cardboard boxes, and — occasionally — between the bed covers on a summer night. Their menacing rear pincers and the old ear-crawling legend give them a fearsome reputation, but they are among the most harmless pests on this list: they don’t bite meaningfully, don’t spread disease, and are often beneficial in the garden. What earwigs are is seasonal and moisture-driven. Each June and July, populations that have built up in damp mulch and leaf litter push indoors in search of food and shelter, a predictable surge that Health Canada documents and that Ontario pest operators see every summer. Understanding that timing is the key to keeping them out.

Identification

An adult earwig is 12–20 mm long, flattened, and reddish-brown to dark brown, with a pair of curved pincers (called cerci) projecting from the tip of the abdomen. Males have stout, strongly curved pincers; females’ are straighter and slimmer. Earwigs have short leathery wing covers over rarely-used wings, thread-like antennae, and they move quickly, often waving the abdomen. The pincers are used for defence, courtship, and folding wings — not for harming people.

Earwigs are sometimes confused with rove beetles, which share an elongated body and short wing covers but lack the signature pincers. The pincers make the earwig one of the easiest household insects to identify at a glance.

Life Cycle

Earwigs are unusual among insects for their maternal care. A female overwinters in the soil and, in late winter or early spring, lays a cluster of 20 to 60 eggs in an underground chamber. She guards and cleans the eggs — grooming off mould — until they hatch, then tends the first-stage nymphs for a time. Nymphs resemble small, pale adults and develop through four to five moults over the summer, gaining their full pincers and colour as they mature. There’s typically one generation per year in Ontario. This overwintering-adult strategy is why a mild winter — like 2025–26 — leaves more survivors and drives the following summer’s surge.

Habitat & Behaviour

Earwigs are nocturnal and strongly moisture-seeking. By day they cram into cool, dark, damp harbourage — under mulch, stones, boards, and garden debris, in leaf litter, and beneath flowerpots. At night they emerge to forage, and after rainy stretches their crowded outdoor hiding spots push them to explore foundations, fences, and walls, where they find their way indoors through small gaps. They are gregarious, often clustering in numbers, and they leave a mild odour when disturbed or crushed. Indoors they’re accidental invaders rather than breeders — they don’t establish reproducing populations inside the way silverfish do.

Diet

Earwigs are omnivorous scavengers. Outdoors they eat aphids, insect eggs, mites, and decaying plant matter, which makes them useful garden predators — but they’ll also nibble tender shoots, flower blossoms, and soft fruit, occasionally becoming garden pests when abundant. Indoors they scavenge crumbs, other insects, and organic debris. They don’t feed on structural materials, fabrics, or stored dry goods in any significant way, so their diet is a garden and nuisance concern, not a household-damage one.

Signs of Infestation

• Live earwigs indoors at night, especially in damp rooms — bathrooms, basements, laundry areas, and kitchens.
• Clusters under objects outdoors — flowerpots, mulch, boards, and debris near the foundation.
• Ragged notches and holes in garden plant leaves, flower petals, and soft fruit.
• A faint odour when they’re disturbed or crushed.
• Earwigs in damp stored items — cardboard boxes, firewood, and outdoor cushions brought inside.

Damage Caused

Earwigs cause no structural or property damage indoors — no chewed wood, no ruined fabric, no contaminated food stores. Their damage is confined to the garden, where large populations can chew ragged holes in the leaves, blossoms, and soft fruit of dahlias, marigolds, lettuce, strawberries, and similar tender plants. Even there, the harm is usually cosmetic and offset by the aphids and insect eggs earwigs eat. Indoors, the only real “cost” is the startle factor of finding them and, in heavy years, the effort of clearing them out.

Health Risks

Earwigs are not a health threat. Health Canada states plainly that “despite their scary appearance and reputation, earwigs are not directly harmful to humans.” They don’t transmit disease, they’re not venomous, and their pincers can at most deliver a harmless pinch that rarely breaks skin. The ear-crawling myth has no basis — earwigs have no interest in and no ability to nest in human ears. For homes and businesses, they’re purely a nuisance, though a visible infestation in a restaurant or hospitality setting is still an appearance problem worth resolving.

Seasonal Activity in Ontario

Earwig activity follows a tight Ontario calendar. Adults overwinter in soil, females lay eggs in late winter, and nymphs develop through spring. The pest-pressure window opens in June, when Health Canada notes earwigs begin wandering into homes, and peaks through July and August as populations mature and summer humidity crowds their outdoor harbourage. A wet spring and mild winter — the 2026 combination across the GTA — amplify the surge, as our June 2026 earwig alert detailed. Activity winds down through the cool of fall, and by winter the adults are back underground. Acting in early summer, before the peak, is far easier than fighting established numbers in August.

Where They Hide

Outdoors: under mulch, stones, boards, logs, and flowerpots; in leaf litter, dense ground cover, and any damp debris against the foundation. Indoors: in the cool, damp rooms they wander into — under sinks, in basement and laundry-room corners, behind baseboards, in floor drains, and inside damp boxes and firewood carried in from outside.

How They Enter Homes

Earwigs slip in through gaps around doors and windows, cracks in the foundation, weep holes, gaps where utilities enter, and under thresholds with worn weatherstripping. They also hitch inside on firewood, outdoor cushions, potted plants, and damp cardboard. Because they’re drawn to the foundation by moisture, a damp, debris-filled perimeter is effectively an invitation — which is why the fix starts outside.

Prevention Tips

1. Clear a dry, debris-free band at least 30 cm (1 ft) around the foundation — remove mulch, leaf litter, and boards.
2. Fix leaks and downspouts and direct drainage away from the foundation; run a dehumidifier in damp basements.
3. Seal gaps around doors, windows, the foundation, and utility penetrations with caulk.
4. Replace worn door sweeps and weatherstripping where light shows underneath.
5. Set simple traps — rolled corrugated cardboard secured with an elastic, or a shallow tin of oil sunk in the soil — and check daily, dropping captured earwigs into soapy water.
6. Tidy the yard: don’t let grass clippings, fallen leaves, or old wood pile up near the house.
7. Inspect firewood, potted plants, and outdoor items before bringing them indoors.

Health Canada notes the best time to apply control products is warm, dry weather in June or early July, in the evening when earwigs are active — the same window when a perimeter cleanup pays off most.

DIY vs. Professional Treatment

For a few stray earwigs, perimeter cleanup, moisture control, and traps usually do the job — earwigs are one of the more manageable pests once you remove their dampness and shelter. But a heavy or recurring infestation calls for a professional to locate the outdoor harbourage sites, seal entry points, and apply registered products safely around children and pets. As Health Canada emphasises, finding and treating the outdoor source is the effective long-term solution. Sani IQ’s integrated approach treats the source and the perimeter, not just the earwigs you spot indoors, and stands behind the work with a Pest-Free-Or-It’s-Free guarantee. Explore general insect control pricing or request a quote.

References

• Health Canada — Earwigs
• University of Minnesota Extension — Nuisance Insects

Last updated: July 16, 2026 · Reviewed by Sani IQ licensed technicians