Earwigs: Mostly Harmless, Mostly a Moisture Problem

Earwigs look like they belong in a horror movie — the pincers, the dark armor, the flat body sliding under a doormat at midnight. The folk name comes from an old superstition that they crawl into sleeping people's ears and lay eggs in the brain. They don't. They don't bite (the pincers can pinch but rarely break skin), don't sting, don't carry disease, and don't damage homes. They're mostly a nuisance pest that thrives in damp conditions and crashes naturally when those conditions change.

The most common species in U.S. homes is the European earwig (Forficula auricularia), an invasive introduced in the early 1900s and now found nationwide. Native species exist but rarely enter structures in numbers.

Identification

Adults are 12–20mm, dark reddish-brown, elongated, with the trademark forceps-like cerci at the tail end. Males have curved pincers; females have straight ones. They have wings folded under short wing covers but rarely fly. Active mostly at night.

Don't confuse with:

• Rove beetles — similar elongated body but no pincers. Larger species like devil's coach horse have a defensive curl pose that mimics scorpions.
• Silverfish — silver-gray, three tail appendages (not pincers), fish-like wiggling movement.

Why they're in your house

Earwigs are not house pests by preference — they're outdoor scavengers that come indoors when outdoor conditions become unsuitable. The three primary drivers:

• Dry weather drives them inward. Earwigs need moisture; a long hot dry stretch sends them searching for damp microclimates indoors.
• Heavy outdoor populations adjacent to the structure. Mulch beds, leaf piles, ground covers, and woodpiles within 3 feet of the foundation seed indoor invasions.
• Easy entry under doors, around windows, and through wet basement walls. Earwigs flatten to slip through very thin gaps.

Control strategy

Outdoor (the actual fix)

• Move mulch back from the foundation — keep at least 12 inches of clear soil or gravel between mulched beds and the building wall.
• Remove leaf piles and clutter — boards, stacked pots, woodpiles, and decorative stone all provide harborage.
• Improve grading and drainage — eliminate puddling within 5 feet of the foundation. Check that downspouts discharge away from the building.
• Trap with rolled newspaper or short pieces of garden hose placed in the garden at dusk. Earwigs hide inside; collect and dispose in the morning. Effective for monitoring outdoor populations.

Indoor (the symptom)

• Seal under exterior doors with proper sweeps. Most earwig entry happens here.
• Caulk around window and door frames on the lower portion of exterior walls.
• Run a dehumidifier in basements and crawlspaces. Earwigs cannot sustain populations indoors at humidity below ~50%.
• Vacuum visible earwigs and dispose outside. They will not establish in a dry home.

Pesticide use

Generally unnecessary. If outdoor populations are severe, a perimeter pyrethroid (bifenthrin, lambda-cyhalothrin) applied as a barrier 3 feet wide around the foundation and on the lower wall in late spring or early summer reduces entry significantly. Granular baits (containing carbaryl, indoxacarb, or boric acid) scattered in mulch beds work better in some climates and are easier to apply.

Indoor spraying is essentially useless — earwigs don't reproduce indoors, so killing the visible ones doesn't change population dynamics.

Do they damage plants?

Yes, occasionally. Earwigs feed on decaying organic matter, small insects, and young plant material — they can chew small irregular holes in seedlings, soft fruit (strawberries, peaches), and dahlia/marigold flowers. Damage is usually cosmetic and doesn't warrant heavy pesticide use. Trap with hose pieces near vulnerable plants.

Frequently asked questions

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