Common Earwig
Forficula auricularia
The common earwig is an occasional pest in commercial settings, where its nocturnal habit and preference for moist environments can lead to infestations in food preparation areas, storage rooms, and commercial kitchens. In food handling facilities, earwig presence represents a contamination risk and a potential non-conformance during food safety audits.
While earwigs do not pose a direct structural threat, their ability to exploit moisture-damaged walls and clogged drainage areas means their presence is often an indicator of underlying moisture management issues.
Commercial greenhouses and garden centres face the greatest direct economic risk, as earwig feeding on seedlings, flowers, and produce can result in significant product damage and increased rejection rates.
Habitat
In commercial environments, earwigs exploit structural moisture problems that create humid harbouring conditions in wall voids, beneath floor drains, under commercial refrigeration equipment, and within floor-wall junctions.
Facilities with outdoor plant material, mulch landscaping, or accumulated organic debris adjacent to entry points face the highest ingress pressure. Interior discovery of earwigs should trigger a moisture audit — particularly investigation of drainage functionality, condensation on cold pipes, roof leak history, and HVAC condensate management.
Commercial kitchens and food storage areas are most frequently affected due to residual moisture from cleaning operations.
Active Areas
Windsor
Tecumseh
LaSalle
Amherstburg
Lakeshore
Essex
Kingsville
Leamington
Chatham-Kent
High prevalence in Chatham-Kent. Earwigs are extremely common in gardens, mulched beds, and around building perimeters throughout the region. Summer invasions of basements and ground-floor rooms are very common.
St. Thomas
High prevalence. Earwigs are one of the most common summer pest complaints in St. Thomas.
Seasonality
Commercial pest monitoring programmes should schedule earwig-specific inspection intervals aligned with peak activity. Interior monitoring traps should be deployed from April through October.
The highest risk period for ingress and contamination is May through August, coinciding with peak outdoor population and warm, wet weather. Exterior treatment applications are most effective when applied in May–June before populations reach peak density.
Facilities should include earwig activity in their monthly pest trend reports and set corrective action thresholds appropriate to the facility’s food safety risk category.
Spring
Summer
Autumn
Winter
Appearance
For commercial pest identification purposes, the earwig is 12–25 mm in length, dark brown to reddish-brown, distinctly flattened, and equipped with forcep-like terminal pincers (cerci) that are unmistakable among common building pests.
The flat body profile enables the insect to exploit extremely narrow harbouring sites such as gaps beneath equipment bases, floor drains, and crevices in food storage shelving.
Staff conducting facility inspections should be trained to recognise the pincer structure as the defining identification feature. Photographic documentation for pest logs should capture a lateral view showing body flatness and a dorsal view showing the pincers.
- Large curved pincers (cerci) at the tail end — male pincers are strongly curved, female pincers are straighter
- Flat, elongated body well-adapted for hiding in narrow cracks and crevices
- Short, folded wings present but earwigs rarely if ever fly
- Strictly nocturnal — hides in moist, dark sheltered locations by day
- Frightening appearance but essentially harmless to humans — pincers cannot pierce skin effectively
- Strong maternal behaviour — female guards eggs and young nymphs in soil nest
Behaviour
Earwig behaviour has several implications for commercial pest management. Their strong thigmotaxis means they are almost always found pressed against surfaces — in crevices, beneath equipment, within packaging folds — rather than moving in the open, making routine inspection of harbouring sites essential.
Their nocturnal activity means daytime inspections may significantly undercount populations; overnight monitoring using cardboard roll traps or sticky traps placed in harbouring areas will give a more accurate population picture.
Their omnivorous diet means that food debris, moisture, and organic build-up in drains and floor joints all constitute attractants. Populations build rapidly in warm, wet conditions, so proactive moisture management is the most effective long-term control strategy.
Lifecycle
Females lay clutches of 70–100 smooth, oval, white-to-cream eggs in underground chambers in late winter or early spring. The female remains with the eggs throughout incubation (approximately 7 weeks), turning and cleaning them to prevent mould. She then guards first-instar nymphs until they disperse after their first moult. Nymphs pass through four instars over 40–60 days to reach adulthood. One generation per year in Ontario.
Egg
Eggs are an entirely subterranean phase occurring from late winter through spring.
They are not directly relevant to interior facility management but indicate that outdoor populations are actively reproducing adjacent to the building. Monitoring exterior harbouring sites in March–April provides early warning of the season’s population level.
Nymph
Nymphs represent the building population during June–August, when the combination of high outdoor density and warm, moist weather creates maximum ingress pressure on commercial facilities.
Monitoring traps placed at foundation-level exterior entry points should be checked weekly during this period. Interior nymph sightings indicate that exclusion barriers have been breached.
Adult
Adults are the life stage of greatest relevance to commercial facility inspections.
Their year-round survival (as overwintering individuals) means that earwig pressure is not strictly seasonal — facilities with interior moisture issues may harbour adults through winter. Peak inspection and control effort should target March through October, with the highest pressure expected May through August.
Signs You May Have a Problem
- Earwigs found in pest monitoring sticky traps placed along interior perimeter walls, especially near drains or moisture-prone zones
- Staff reports of earwigs in food preparation areas, under commercial refrigeration equipment, or near floor drains
- Earwig sightings in food storage rooms or on shelving near the floor level
- Evidence of feeding damage on fresh produce, seedlings, or ornamental plants in commercial greenhouse or garden retail settings
- Earwigs found during inspection behind stored goods, cardboard, or organic debris accumulated on facility floors
- Multiple earwig sightings in a short period in the same area, indicating an accessible harbouring site nearby with a moisture source
- Earwigs discovered in drainage channels or floor drain sumps during facility inspection
Risks & Concerns
In food handling facilities, the discovery of earwigs in food preparation or storage areas represents a potential contamination event that may require documentation and corrective action under HACCP or other food safety management systems. Earwigs can physically contaminate food products and surfaces.
Their presence in a facility is a likely indicator of moisture ingress, drainage issues, or structural deficiencies that may themselves be audit non-conformances.
For commercial greenhouses and garden retailers, direct economic losses from earwig feeding on high-value ornamental plants and seedlings can be substantial. Third-party audit bodies including AIB, SQF, and BRC inspectors treat insect presence in food zones as a serious finding.
Prevention
- Conduct a drainage audit of all floor drains, sumps, and exterior drainage systems — repair any blockages or slow drains immediately
- Remove all organic debris and dense plantings from within one metre of the building perimeter
- Seal all ground-level entry points including gaps around pipes, floor drains, and expansion joints
- Implement a threshold-based monitoring programme using cardboard roll traps or sticky traps along interior perimeter walls in high-risk areas
- Address all identified moisture issues (condensation, roof leaks, plumbing leaks) promptly to eliminate interior harbouring conditions
- Train staff to report earwig sightings immediately and include earwig-specific items in regular pest control inspection checklists
DIY Control
- Deploy commercial sticky traps along interior perimeter walls and under equipment to monitor and partially suppress interior populations
- Apply exterior granular insecticide bait (labelled for commercial use) in landscaped areas adjacent to the building
- Ensure all floor drains have properly fitting covers when not in active use to prevent harbouring and movement through the drain system
- Document all sightings with date, location, and count in the facility pest log and initiate corrective action per the written pest management plan
Professional Control
- Professional integrated pest management programme with scheduled inspections, threshold-based treatment decisions, and full documentation
- Exterior perimeter barrier treatment using commercial-grade residual insecticides applied by licensed applicators
- Interior monitoring with analysis of catch trends to identify harbouring hotspots and guide targeted treatment applications
- Structural moisture assessment and remediation recommendations integrated into the facility's pest management plan
Frequently Asked Questions
Are the earwig’s rear pincers dangerous?
Earwigs pose no physical risk to staff or customers. Customer complaints about their appearance should be addressed by reducing the population through exterior treatment and harborage reduction.
Why are earwigs attracted to damp areas?
In commercial settings, earwig entry is most common through ground-level gaps near landscaped areas with heavy mulching. Review and reduce mulch depth near the building foundation and ensure drainage is adequate.
Do earwigs damage plants?
In commercial greenhouses or facilities with indoor plants, large earwig populations can cause plant damage. Manage by reducing moisture and harborage around the growing area.
Do earwigs bite?
Earwigs present no meaningful biting risk.
How do I prevent earwigs from entering my home?
Reduce mulching and dense ground cover immediately adjacent to the building. Address drainage issues that create persistently damp soil near the foundation. Seal ground-level gaps and apply exterior perimeter treatment.
Do earwigs breed indoors?
Indoor earwig breeding is uncommon. Persistent indoor earwig presence usually indicates ongoing entry from outside rather than an established indoor population.