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 citrus. 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. 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. If trunk wrappers cannot be removed and treatments are needed, the preferred method is to apply an insecticidal bait or broad-spectrum insecticide (such as a pyrethroid or organophosphate) directly into the trunk wrapper. This can be done with a measuring scoop for bait products or with a handgun for liquid products. Foliar applications of insecticides, such as with an air blast sprayer, are not highly effective against earwigs, although some mortality will occur if the applications are made at night while some earwigs are feeding on the tree canopy.

PUBLICATION

UC IPM Pest Management Guidelines: Citrus
UC ANR Publication 3441
Insects, Mites, and Snails
E. E. Grafton-Cardwell, Kearney Agricultural Center, Parlier
J. G. Morse, Entomology, UC Riverside
N. V. O‘Connell, UC Cooperative Extension, Tulare County
P. A. Phillips, UC IPM Program, UC Cooperative Extension, Ventura County
C. E. Kallsen, UC Cooperative Extension, Kern County
D. R. Haviland, UC Cooperative Extension, Kern County
Acknowledgments for contributions to Insect, Mites, and Snails:
J. Barcinas, E. S. I., Corona, CA
R. Dunn, Badger Farming County, Exeter, CA
J. Gorden, Pest Management Associates, Exeter, CA
H. Griffiths, E. S. I., Corona, CA
D. Machlitt, Consulting Entomology Services, Moorpark, CA
C. Musgrove, retired entomologist, Riverside, CA
K. Olsen, S & J Ranch, Pinedale, CA
T. Roberts, E. S. I., Corona, CA
J. Stewart, Pest Management Associates, Exeter, CA
P. Washburn, Washburn & Sons Citrus Pest Control, Riverside, CA
K. Godfrey, USDA Biological Control, Sacramento
D. Headrick, California Polytechnic State University, San Luis Obispo
B. Faber, UC Cooperative Extension, Ventura County
J. Kabashima, UC Cooperative Extension, South Coast Research and Extension Center

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