[Please note, this is a test version only. You may visit the current Orchard Pest Management pages at http://jenny.tfrec.wsu.edu/opm]
Forficula auricularia Linnaeus (Dermaptera: Forficulidae)
The European earwig is chiefly a garden pest but occasionally attacks tree fruits. Adults and nymphs can damage pome and stone fruits. The name earwig comes from an old, unfounded superstition that the pest invades the ears of humans.
Adult earwigs in herbicide strip (apple orchard) (E. Beers, July 2007)
HostsEarwigs attack a wide range of plants including vegetables, flowers, tree fruits, berries, ornamental trees and shrubs. At times, they can be scavengers or predators, feeding on decaying vegetation or insects such as aphids.
Life stagesEgg: The egg is small, oval and pearly white.
Nymph: The young earwig passes through four instars. The immature earwig starts out creamy white but the cuticle soon hardens and darkens in color. It looks like the adult, except it is wingless. Adult: The full-grown earwig is brownish black, about 3/4 inch (2 cm) long and has a pair of forceps-like appendages at the rear. The male has curved forceps and the female's are straight. It has short, leathery forewings under which are tucked a rear pair of wings that look like tiny fans when open, but it rarely flies. Some species of earwigs have scent glands on their abdomen that release a foul smelling odor, which is probably for defense.
Adult and immature European earwig (J. Brunner)
Adults go into the soil in the fall to form earthen cells in which they live in pairs. The females lay eggs in clusters of 20 to 50 during the fall and spring. The cells containing the eggs are in the top 2 to 3 inches of soil. In the spring, the females open the cells and the nymphs emerge. Earwigs are semisocial and will look after their young in the early stages. After leaving the ground, they hide in deep crevices or under loose bark on trees. The nymphs mature in midsummer, and a partial second generation may develop some years. As earwigs rarely fly, infestations in orchards spread slowly.
DamageEarwigs damage both leaves and fruit. Leaf damage is unsightly but of little concern on mature trees. On young seedlings, however, the earwig's feeding on shoot tips can stunt tree growth. Damage on tree fruit crops is usually confined to shallow, irregularly shaped feeding areas on the surface , but occasionally an earwig will bore through and feed on the flesh near the pit of stone fruits. Earwigs will get into any area damaged by other pests, such as birds and caterpillars.
Earwig damage to apple (J. Dunley)
Earwig damage to peach (E. Beers, August 2007)