Earwigs                                               EL 26

by G.R. Nielsen, Former Extension Entomologist, Plant and Soil Science Department

The European earwig, a native of Europe, is now an important pest in many areas. It can damage fruits, flowers, and
vegetables, particularly when the plants are small, and it is very objectionable in and about the house.

Damage to gardens can be serious. Among the plants attacked by earwigs are asters, dahlias, carnations,
chrysanthemums, gladioli, marigolds, rose, zinnias, apricots, peaches, raspberries, beans, carrots, celery, corn, lettuce,
and potatoes. When the pest invades the home, its objectionable appearance, unpleasant odor, and habits of lurking
among foodstuffs or clothing and of dropping onto the table, make it a major nuisance.

Description and Life History

The adult earwig is about 19 mm (3/4 inch) long and reddish brown in color. In growing, the insect sheds its skin, or
molts, four times. All stages of the young are similar in general appearance to the adult but smaller. The males have a
pair of large, curved forceps at the rear of the body whereas those of the females are smaller and nearly straight. These
pincers are harmless, although the insect tries to pinch with them when picked up. The adult has wings but seldom flies.

Each female lays as many as 60 round, pearly-white eggs in small nests in the top 5 cm (2 inches) of soil. The mother
tends the young in the nest for the first 2 weeks. When they are about 6 mm (1/4 inch) long, they leave the nest in
search of food. The insects usually reach the adult stage in about 70 days. About one-fifth of the females lay a second
batch of eggs in June. The young from these appear in July and August. Earwigs live only 1 year. They overwinter as
adults, but many die during the winter. The survivors are mainly females, which die in the summer after rearing their
young.

Habits

In their search for food and shelter, earwigs crawl over the ground and readily climb houses, fences and trees. They
forage at night and hide during the day in cracks, hollow stalks of leaf whorls of plants, tubular lawn furniture, and
hollow aluminum doors, and under the husks of corn cobs. Their invasion of houses begins sometime in July.

Traps are being used with success rather than insecticides in some areas. These traps consist of two 7.6 cm (3 inches)
boards with grooves 6 mm (1/4 inch) wide and 6 mm (1/4 inch) deep running the length of the boards. Grooved
surfaces face each other, with grooves matching, and are secured by a rubber band. Place these traps, standing on
end, in shrubbery and hedges, around trees, and in areas where earwigs commonly seek shelter. Twenty traps per city
lot are recommended, to be cleared at least twice a week by shaking the contents into a pail containing a small amount
of oil or soapy water.

Chemical Control - Pesticides

Indoors:
In the latter part of the summer, earwigs sometimes cause further annoyance by entering houses. If it becomes
necessary to spray indoors, use a household spray labeled for use indoors against earwigs.

Spot treat along baseboards and drainpipes, and under the edges of carpets and rugs. Do not treat furniture or floor
areas where children play.

Outdoors:
In populated areas, control measures against this insect are most effective when they are applied on a neighborhood or
community basis. Because earwigs move about very freely, a garden to which chemicals have been applied may soon
become infested again, unless those nearby are treated at the same time.

The best time to apply insecticides is during warm, dry weather when the earwigs are young. In many parts of
Vermont, this means late June or early July. The insecticides may be applied as dusts or sprays. Apply them along
building foundations, sidewalks, fences, and woodpiles, and also to the trunks and crotches of trees, under shrubs and
near other ground cover that affords a hiding place for this insect. Do not irrigate or water treated areas for at least
two nights after the application. Treatment later in the summer is much less effective.

Select and use only those products that are registered for use in your particular garden situation.

It may be necessary to repeat applications in from 7 to 10 days. Use dust only where children and pets cannot contact
dusted surfaces.

(Adapted from "Control of European Earwigs," Pub 1097, Information Services - Agriculture Canada, Ottawa.)