Primarily European earwig (Forficula auricularia)
Pest description and crop damage Earwigs are slender, reddish-brown insects with a pair of "forceps" or "pinchers" on the end of their abdomen. A mature adult earwig ranges from 0.5 to 0.75 inch in length and has wings tucked under a short elytra sheath. They can emit a foul odor when disturbed. Immature earwigs are similar in appearance to the adults except smaller, wingless and may be lighter in color. Earwigs are nocturnal and hide under tree bark or soil debris during the day. They prey on soft-bodied insects and scavenge on decaying vegetation. Earwigs can climb trees and chew holes between leaf veins, but this damage is rarely of any consequence. Earwigs can become pests when they chew irregular, shallow holes on ripening or overripe fruit.
Biology and life history Earwigs overwinter just below the soil surface as both eggs and adults. In spring, females lay 20 to 50 smooth white to cream-color eggs in the soil, and then stick around to nurture the immature nymphs. The immatures grow through four to five nymphal stages to become adults by late summer. In fall, females may lay more eggs. Earwigs are active at night. During the day, they hide in moist, shady places such as compost piles or beneath stones, boards, and debris.
Pest monitoring Periodically scout fruit trees for signs of leaf damage. If damage to young leaves is detected, confirm the presence of earwigs by placing corrugated cardboard, flat boards, roofing tiles or similar material on the ground that will provide daytime shelter for the nocturnal earwigs. Check under or within these materials each morning for presence of the insects. Infestations spread slowly as earwigs rarely fly. For tree-ripened fruit, be sure to monitor earwig populations prior to harvest.
Earwigs can be monitored and trapped in small boxes filled with newspaper or straw placed at the base of the tree or in strips of corrugated cardboard strapped around the tree trunk. Earwig abundance can be reduced by removing weeds and plant debris away from the base of trees. Banding tree trunks with plastic wrap covered with sticky adhesive can prevent earwigs from moving into the tree canopy.
These treatments target and intercept the immature and adult earwigs as they climb into the tree canopy at night.
Management-chemical control: HOME USE
- azadirachtin (neem extract)-Some formulations are OMRI-listed for organic use.
- carbaryl-Highly toxic to bees.
- gamma-cyhalothrin-Highly toxic to bees.
- insecticidal soap-Not recommended for use on yellow-skin nectarine varieties. Some formulations are OMRI-listed for organic use.
- kaolin clay-Repels some insect pests when applied as a spray to leaves, stems, and fruit. OMRI-listed for organic use.
- pyrethrins-Highly toxic to bees. Some formulations are OMRI-listed for organic use.
- spinosad-Toxic to bees. Some formulations are OMRI-listed for organic use.
- zeta-cypermethrin-Highly toxic to bees.
Management-chemical control: COMMERCIAL USE
Spring and summer sprays
- carbaryl (Carbaryl 4L) at 2 to 3 quarts/A. REI 12 hr. PHI 3 days. Apply on trunk and soil around trees. Do not exceed three in-season applications per year. Extremely toxic to aquatic invertebrates; avoid spray drift and runoff to surface waters.