European earwig, Forficula auricularia
Earwigs found in Colorado were introduced in the 1950s, they are a common nuisance pest both indoors and outdoors. Occasionally, earwigs damage soft parts of plants, however, they mainly feed on smaller insects, including plant pests, like aphids.
The European earwig is about 1.6 cm (5/8 inch) long and brown with a dark red head. Younger earwigs look similar to adults, just smaller. Males are more strongly curved than females. A distinctive feature of earwigs is the pair of prominent forceps at the rear of the body. The European earwig is the only earwig found throughout most of Colorado. In extreme southern areas of the state, a second species, ring-legged earwig may be found.
- The common earwigs found in Colorado are an introduced insect that arrived in the state during the 1950s.
- Occasionally, earwigs damage soft parts of plants. However, the main food of earwigs is insects, including plant pests such as aphids.
- Earwigs like to hide in dark, tight-fitting areas during the day and often become nuisance problems as a result.
- Earwigs can be physically prevented from entering homes or trapped in rolled up newspapers.
Adult male and female earwigs on a flower. Image credit: Whitney Cranshaw, Colorado State University, Bugwood.org.
Adult male European earwig. Image credit: Whitney Cranshaw, Colorado State University, Bugwood.org.
Earwig feeding injury. Image credit: Whitney Cranshaw, Colorado State University, Bugwood.org.
Earwig adults and brown garden snail on alium flower. Image credit: Whitney Cranshaw, Colorado State University, Bugwood.org.
Life history and habits
During the day they hide in dark, confined spaces, especially if it is moist. Typical hiding spots include under rugs or potted plants, in stacks of newspapers or similar locations. Common hiding spots outside include under rocks or stacked wood, in ear tips of sweet corn, and under various kinds of debris. Peak problems with earwigs occur mid-July through mid-September.
Injury and nuisance
European earwigs are active at night and occasionally damage leafy plants like lettuce and some flower blossoms. They are often injuries caused by other insects like leaves curled by aphids and holes in fruit. While European earwigs can be a nuisance indoors and outdoors, they may actually be considered beneficial since they feed on many plant pests such as aphids, mites and insect eggs. However, there are situations where control of earwigs is desired.
Clearing the area around the home of sheltering debris (including mulches) used by earwigs is an effective preventative measure. All cracks around doors and windows should be sealed to prevent entry.
Many earwigs can be trapped with rolled newspapers containing a food bait, or oil-based baits such as vegetable or fish oil in a small cup, which may help reduce numbers.
Alston, D., and A. Terbeau. 2011. European Earwig. Utah State University – Extension. Available https://extension.usu.edu/pests/research/european-earwig
University of California. 2012. Earwigs. University of California – Agriculture and Natural Resources. Available https://ipm.ucanr.edu/PMG/PESTNOTES/pn74102.html