How to Manage Pests
UC Pest Management Guidelines
Scientific Name: Forficula auricularia
(Reviewed 2/17, updated 2/17)
In this Guideline:
Description of the Pest
The introduced European earwig 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 (cerci) that resemble forceps. Most species have wings under short, hard wing covers, but earwigs seldom fly. Males have stout, strongly curved cerci that are widely separated at the base while females possess slender, straight pinchers that are close together. Earwigs use these cerci to protect themselves and to grab and hold prey. 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 emerging from the soil in search of food. Earwigs generally have one or two generations a year. They can be active year round.
Earwigs feed on dead and living insects and insect eggs, other organisms, and on succulent plant parts. Earwig nymphs will climb trees and feed on buds, leaves , and fruit of trees during the spring flush months (March through May). Once they molt into adults and the foliage hardens, they move back down to the soil and stop damaging trees.
They can be especially problematic on young trees with trunk wraps or cardboard guards, in which they reside. The cause of damage can be difficult to distinguish from that of other chewing pests that hide during day and feed at night, including worms, brown garden snail, Fuller rose beetle, and June beetles.
If you suspect that earwigs are causing damage in young trees, lift and shake or sharply tap any trunk wraps and look for earwigs dropping to the ground, where they quickly scurry for cover. Remove trunk wraps when they are no longer needed for sunburn or rodent control, thereby reducing earwig numbers. If trunk wraps cannot be removed and insecticides are needed, apply a broad-spectrum insecticide directly into the trunk wrap.
In mature trees, near the time of petal fall when young fruit could be damaged, use a beating sheet or net to shake the trees and collect earwigs to determine if earwigs are infesting the trees. Where damage to young fruit is occurring, foliar applications of insecticides with an air blast sprayer can be effective; however, only the most broad-spectrum insecticides reduce their numbers and these insecticides may affect natural enemies needed for other pests.
UC IPM Pest Management Guidelines: Citrus
Insects, Mites, and Snails
E. E. Grafton-Cardwell, Entomology, UC Riverside and Kearney Agricultural Center, Parlier
Acknowledgments for contributions to Insect, Mites, and Snails:J. Barcinas, E.S.I., Corona, CA
R. Dunn, Badger Farming Co., 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
T. Shea, UC Cooperative Extension, Riverside County
J. Stewart, Pest Management Associates, Exeter, CA
P. Washburn, Washburn & Sons Citrus Pest Control, Riverside, CA