How to Manage Pests

UC Pest Management Guidelines

DESCRIPTION OF THE PEST

The introduced European earwig (family Forficulidae) is the most common of several earwig species that can occur in avocado. Adults are about 0.75 inch long, reddish brown, and have a pair of prominent tail appendages that resemble forceps. Most species have wings under short, hard wing covers, but earwigs seldom fly. Immature earwigs resemble small, wingless adults.

Earwigs feed mostly at night and hide during the day. Common hiding places include bark crevices, mulch, topsoil, protected (touching) plant parts, and under trunk wraps. Females lay masses of 30 or more eggs in soil. Nymphs are whitish and remain in soil until their first molt, after which they darken and begin searching for food. Earwigs generally have one or two generations a year. They can be active year round.

DAMAGE
Earwigs feed on dead and living insects and insect eggs, other organisms, and on succulent plant parts. Earwigs occasionally damage buds and leaves on young or newly grafted trees. They can be especially problematic on trees with trunk wrappers or cardboard guards. The cause of damage can be difficult to distinguish from that of other chewing pests that hide during day and feed at night, including brown garden snail, Fuller rose beetle, and June beetles.

MANAGEMENT

If you suspect that earwigs are causing damage, lift and shake or sharply tap any trunk wrappers and look for earwigs dropping to the ground, where they quickly scurry for cover. Alternatively, place a folded newspaper or burlap bag near the base of several trees with chewed foliage. Check these traps or earwig hiding places the next morning. Cans with sardine or tuna fish oil are highly attractive to earwigs, which will climb into containers and drown. It may be necessary to cover liquid traps with heavy screening to exclude feeding by domestic and wild animals drawn to the fish odor. Remove trunk wrappers where pests hide when wraps are no longer needed, thereby reducing earwig populations. Earwigs rarely are abundant enough to warrant chemical treatment, except on young trees bordering uncultivated areas. Check with your farm advisor or County Agricultural Commissioner about registration status of baits for treating earwigs.

PUBLICATION

UC IPM Pest Management Guidelines: Avocado
UC ANR Publication 3436
Invertebrates
P. A. Phillips, UC IPM Program, UC Cooperative Extension, Ventura County
B. A. Faber, UC Cooperative Extension, Santa Barbara/Ventura counties
J. G. Morse, Entomology, UC Riverside
M. S. Hoddle, Entomology, UC Riverside
Acknowledgment for contributions to Invertebrates:
M. Blua, Entomology, UC Riverside
P. Oevering, UC Cooperative Extension, Ventura County
D. Machlitt, Consulting Entomology Services, Moorpark, CA
T. Roberts, Integrated Consulting Entomology, Ventura, CA
B. B. Westerdahl, Nematology, UC Davis

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