Earwigs have large, pincers-likeprotrusions at the rear of the body,which give them an evil appearance,but they dont harm people directly.Still, they can cause people problemsby feeding on flowers and vegeta-bles outdoors, by crawling into thehome, and by congregating underwell caps.

The first American report of aEuropean earwig (Forficula auriculari)came from Newport, Rhode Islandin 1901. Until 1982 European earwigreports in Wisconsin were limited tothe Lake Michigan shoreline. But inthe years since, earwig infestationshave spread fast across Wisconsin.

The name earwig derives froma false European superstition accord-ing to which these insects enter theears of sleeping people and bore intothe brain. In fact, earwigs rarelybiteusually when sat upon orhandledand their bite is onlymildly painful.

Identification and life cycle

Adult European earwigs arereddish brown and about 34 inchlong. Their most distinctive featureis the prominent, pincers-like cerci(pronounced sir-see) on the end ofthe abdomen. Earwigs use their cercifor defense, capturing prey, andsensing the environment. The cercican pinch you if you stick a fingerbetween them, but they cant breakthe skin. Male earwigs have curvedcerci that are thicker at the base,while females have thin, straightcerci.

In Wisconsin, pairs of earwigsoverwinter by digging 23 inchesinto the soil to hibernate. Sometimeduring the winter or early spring the

female lays 2530 eggs. Males leavethe hibernation sites first, and thefemales follow in late May. You maysee your first earwig of the summerby mid-June. In some parts of thecountry the females enter the soilagain to deposit a second set of eggs,but Wisconsin earwigs most likelyproduce just one generation peryear. Unusually wet springs andsummers often intensify earwiginfestations.

Earwigs eat an omnivorous dietof other insects and plants. This dietcan be beneficial: earwigs feed onaphids, mites, fleas, and insect eggs.Unfortunately, in gardens theymunch on dahlias, marigolds,lettuce, potatoes, and hostas. Theywill also feed on mosses, lichens,and algae. Earwigs are active atnight and hide during the day inalmost any dark, confined space,particularly if it is moist.

Female earwigs exhibit aninstinct that is very rare amonginsects: they care for eggs andyoung. The females turn, lick, andreposition their eggs. They also bringfood to the newly hatched youngand protect them in the nest. It takesabout 2 months for nymphs tomature.

Earwigs nocturnal activity,quick movements, size, and coloroften cause them to be mistaken forcockroaches. Although, like somecockroaches, earwigs have wings,they fly very badly. Earwigs spreadlargely by infested plant material, cutflowers, and other human activities.

Earwig problemsThe earwigs habit of hiding

leads them into trouble with people.They often come indoors to hide, orthey conceal themselves underoutdoor furniture, hoses, garbagecans, or poor-fitting well caps. Theydo not breed indoors but simplyhide, then become active at night.

Well problemsLoose-fitting well caps provide

an ideal hiding place for earwigs:dark and damp during the day.Once inside a well cap, an earwigmay fall into the water, die, anddecay, thereby increasing bacterialcontamination of the well. Earwigsare not considered a public healththreat and are not associated withany disease; nevertheless, you shouldreplace poor-fitting well caps withvermin-proof caps to prevent anyinsects from contaminating the water.

Plant damageEarwigs eat small holes in plant

leaves during the night. Earwigdamage often appears small com-pared to the large pest populationspresent, and it can be confused withinjuries caused by slugs, cutworms,or even rabbits. Larger plants willtolerate the feeding, but seedlingsand flowering plants can beseverely damaged or killed by densepopulations.

Controlling earwigsP.J. Pellitteri

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female earwig male earwig

You should suspect earwigproblems if you find damage duringthe day but cant find any insects onthe plants. Confirm the presence ofearwigs by checking the plants atnight, or by looking for them congre-gated under boards, firewood, ortree bark next to your plants.

Control Earwigs congregate in areas that

are shaded or filled with lush plantmaterial, boards, debris, or organicmulch. Exposed, sunny yards havefewer problems. Two species of par-asitic fly, including Digonichaetasetipennis, have been introduced tohelp control earwigs naturally. Ingood years these parasites attack andkill over 13 of the earwig population.

You can trap earwigs in rolledup newspapers or in old tuna fishcans baited with fish oil or vegetableoil. Place traps near the problemareas and check them each morning.Shake live insects into a pail of soapywater to kill them.

Converting the backyard to adry, sunny environment with fewhiding places will also help controlearwigs. Remove any shelter sites,prune low-growing bushes, avoidgrowing the earwigs favored foodplants, and destroy moss and algae.Avoid overwatering and dont usethick organic mulches.

ChemicalA variety of insecticides avail-

able to homeowners are labeled forearwig control. You can use the fol-lowing materials as baits, liquids,sprays, granules, or dusts: carbaryl(Sevin), acephate (Orthene), bifen-thrin, permethrin, cyfluthrin, esfen-valerate, and propoxur (Baygon).Products containing diazinon orchlorpyrifos (Dursban) are beingphased out for homeowner use, butexisting stocks can be used up. Readthe label to determine the propersites and usage restrictions.Insecticidal soaps kill earwigs oncontact but do not have a residualeffect on treated areas.

Applying insecticides todaytime hiding places will givemore successful control. Mulchedareas of flowerbeds are often the bestsites to treat. Large volumes areoften needed for adequate coverageso consider using a hose-end typesprayer or apply granules to the soilarea and water them in. Insecticideapplications made late in the day aremost effective.

A common recommendation isto apply insecticides as a barriertreatment. Sprays or dust areapplied to the exterior foundationwalls and a 23 foot swath along theadjacent ground. Flower beds andmulches can also be treated. Manylawn insecticides could be used ongrass, but that would be an extremeresponse to this problem.

IndoorIf earwigs are getting into your

home, caulk cracks and crevices andweather-strip doors to prevent theirentry. Check windows, the junctionof the siding with the foundation,and all outdoor water faucets foropenings that earwigs can squeezethrough. Remove firewood,unneeded plant material, andorganic mulches from the founda-tion area. Create a clean, dry borderalong the foundation and considerreplacing wood chips or bark mulchwith stones or other material thatwill be less attractive to earwigs.Clear debris and leaves from thetroughs of eaves.

Individual earwigs foundindoors may be vacuumed or killedby hand. Many indoor spray clean-ers will kill individuals on contact,as will most ant and roach sprays.But sealing or caulking openings is amore effective and permanentapproach. Earwigs will not breedindoors, so continual problemssuggest constant migration fromoutside.

C O N T R O L L I N G E A R W I G S

Copyright 1999 University of Wisconsin System Board of Regents and University ofWisconsin-Extension, Cooperative Extension.

Author: P.J. Pellitteri is distinguished outreach specialist of entomology, College of Agricultural and Life Sciences, Universityof Wisconsin-Madison and University of Wisconsin-Extension, Cooperative Extension. Produced by Cooperative ExtensionPublications, University of Wisconsin-Extension.

Acknowledgement: Rutgers Cooperative Extension provided the earwig illustrations.

University of Wisconsin-Extension, Cooperative Extension, in cooperation with the U.S. Department of Agriculture andWisconsin counties, publishes this information to further the purpose of the May 8 and June 30, 1914 Acts of Congress; andprovides equal opportunities and affirmative action in employment and programming. If you need this material in an alterna-tive format, contact Cooperative Extension Publications at 608-262-8076 or the UWEX Affirmative Action Office.

This publication is available from your Wisconsin county Extension office or from Cooperative Extension Publications, 45 N. Charter St., Madison, Wisconsin 53715. Phone 608-262-3346; outside Madison, call toll free 877-WIS-PUBS.

A3640 Controlling Earwigs SR-12-01-2M-25

References to products in this publicationare for your convenience and are not anendorsement of one product over othersimilar products. You are responsible forusing chemicals according to the manu-facturers current label directions. Followdirections exactly to protect the environ-ment and people from chemical exposure.