Earwigs are small, nocturnal insects recognized by the prominent pincers, known as cerci, located at the rear of their elongated, reddish-brown bodies. They belong to the insect order Dermaptera and are frequently encountered in damp, dark places. Despite their intimidating appearance, earwigs are not harmful to humans, and the long-held myth that they burrow into the ear canal is unfounded. Their reputation as an invasive and destructive garden pest requires a closer look to separate genuine impact from misconception.
Clarifying Native and Non-Native Status
The question of whether earwigs are invasive depends on the specific species. The species most commonly found in homes and gardens across North America is the European earwig, Forficula auricularia, which is a non-native species. This earwig originated in Europe, Western Asia, and Northern Africa. It was first recorded in the United States in Seattle, Washington, around 1907, and spread quickly across the continent, often hitchhiking in shipments of plants and produce.
An invasive species is defined by its non-native origin and its tendency to cause economic or environmental harm. While the European earwig is widespread and is the primary species associated with pest complaints, it is only one of approximately 22 earwig species found in the United States. Many of those species are native, but the sheer numbers and omnivorous habits of the introduced European earwig have made it the dominant one in many temperate regions.
Identifying Damage and Ecological Impact
Earwigs are generalist omnivores, consuming a wide variety of both plant and animal matter. This contributes to their dual status as both a pest and a beneficial organism. Their feeding habits become noticeable when they chew irregular holes in plant foliage, particularly the petals of delicate flowers like roses, dahlias, and zinnias. Tender seedlings and young plants are especially vulnerable to damage, as earwigs can consume enough tissue to seriously compromise their growth.
Earwigs also target soft fruits, creating shallow gouges or holes in ripe strawberries, apricots, peaches, and sweet corn silks. This damage occurs at night, as they seek shelter in dark, moist locations during the day, such as under mulch or within flower heads. When populations are high, they can become a nuisance indoors, seeking moisture in bathrooms and kitchens or contaminating pantry goods.
The ecological picture is complicated by the earwig’s role as an opportunistic predator. Earwigs routinely feed on pest species such as aphids, scale insects, insect eggs, and mites, providing natural pest control in the garden. In orchards, their predation on pests like the wooly apple aphid can significantly reduce infestation levels. This makes their presence a net benefit unless their population levels become excessive and they begin feeding on cash crops.
Effective Strategies for Control and Prevention
Managing earwig populations effectively involves focusing on the environmental conditions that allow them to thrive, primarily moisture and hiding places. The most effective first step is to reduce damp, dark harborage areas around the home and garden perimeter. This involves clearing away accumulated leaf litter, lawn clippings, boards, and other ground debris where earwigs congregate during the day.
Controlling moisture is also paramount, as earwigs require a humid environment to survive. Repairing leaky outdoor faucets, ensuring proper drainage, and reducing the use of excessive, moisture-retaining mulches near the foundation can make the area less appealing.
Trapping and Barriers
For direct population reduction, simple physical traps can be highly successful. A shallow dish filled with vegetable oil attracts the insects and causes them to drown. Another method involves placing rolled-up damp newspaper or corrugated cardboard near affected plants in the evening. Earwigs will crawl inside to seek shelter by morning, allowing for easy collection and removal the next day. For a non-chemical barrier, a thin layer of diatomaceous earth can be applied to soil or along foundation cracks. This fine powder damages the insect’s protective outer layer, causing dehydration. Indoors, sealing cracks and crevices prevents them from entering.