Battling Earwigs in the Garden

The first time I saw earwigs in the garden, I couldn't believe anything so small could look so mean and nasty. I was about seven at the time. It probably didn't help that my older brother, on seeing my horror, quickly confided that earwigs were famous for burrowing into people's ears and eating their brains from the inside out. Where I grew up in Northern California, earwigs were everywhere, which resulted in my deciding to wear ear plugs made of cotton balls, well, most of the time. This went on until my mother intervened.

Earwigs prefer moist, dark places like under a protective layer of mulch -- which they enjoy eating. Think of it as the insect equivalent of suburban room service. They're also omnivorous, eating plants and dead insects with equal gusto. If it's in the vicinity and doesn't wiggle too much in protest, an earwig will try to make a meal of it. The news isn't all bad, though. Earwigs do plenty of damage in the garden, but they also chow down on destructive pests like spider mites and aphids. For insects, they're tenderhearted, too, taking care of their eggs and young (nymphs) until they can fend for themselves.

If you have an earwig problem, you'll likely find these pests every time you turn over a rock or disturb a layer of fallen leaves. They may also hang out inside leaf clusters or flowers (as in the photo above). They're most active at night, so if you're seeing plant damage that looks like the work of snails and slugs, an earwig infestation may be partly responsible.

What are Earwigs?

Growing to a length of about an inch, earwigs are brown and black in color and have two curved, tong like appendages where a stinger might be on another variety of insect. Technically, they're at the base of the earwig's abdomen. From a non-technical perspective, they have antlike heads and lethal looking pincers bringing up the rear. Even though the pincers (or pinchers) look lethal, they aren't typically used to attack unwary gardeners or their apprehensive children. They're defensive weapons used against other insects. They also perform certain functions during mating -- that I don't care to contemplate.

Two types of earwigs are commonly found in the U.S., the European earwig (Forficula auricularia), which is by far the most abundant, and a ring legged variety found primarily in the Southern states (Euborellia annulipes).

Do Earwigs Bite?

The old story that earwigs like to crawl into the ears of unwary sleepers is just a gruesome not-so-urban myth. It's true they can pinch humans, but they seldom do. The pinch itself is described as more shocking than painful. I maintained an earwig challenged (for the most part) garden for over a decade and was never pinched.

Earwigs are a minor nuisance in small numbers, where they prefer a diet of decaying plant matter and dead bugs. When their numbers get out of hand, though, their nibbling will become more destructive. They will readily consume flower petals, buds, plant leaves, seedlings, fruits and vegetables when dead and decaying matter isn't abundant. They will also expand their territory indoors as their numbers grow, inhabiting basements, sheds, garages and other areas that tend to be dark and somewhat moist.

How to Control Earwigs in the Garden

Earwig eggs and young

Because earwigs prefer moist, dark environments, a good first step in controlling them is to eliminate outdoor locations that attract them in the first place. This is particularly true in early winter and again in spring.

Earwigs reproduce in winter, laying eggs in the soil that will hatch a hungry new generation in springtime. In early spring, new earwigs emerge from the soil looking for shelter and a meal. Here are some steps you can take to control their numbers, especially during these two crucial times of the year:

• Remove mulch from flowerbeds. (This can be a difficult judgment call, especially if you're trying to retain moisture for your plants during hot summer conditions.)
• Remove fallen branches from trees and shrubs. (This will also discourage termites.)
• Rake leaves and dispose of them promptly.
• Monitor compost piles for earwig activity.
• Pay attention to anything placed in the garden (especially in early spring) that will create a moist environment at soil level. This includes lawn furniture and other temporary fixtures like plant pots and decorations.
• Prefer watering in the morning rather than in the evening. Earwigs like it moist, so reducing the moisture in your garden during the time they're most active (at night) is a good thing.
• Eliminate standing water around your home. This can be water inside an old tire, a kiddy pool and even ponding water from a downspout (a bad thing all around). Eliminating standing water will help control mosquito populations, too.
• Turn off exterior lights. Earwigs like the shadows, but they are attracted to light sources at night.
• Install yellow outdoor lights. Most insects dislike yellow light. If you insist on outdoor illumination in the evening, install yellow bulbs to discourage earwig activity. Yellow light will also help control night fliers like moths.

Set Out Earwig Traps

Setting out earwig traps may help control small infestations. Installing traps will give you an idea of how extensive a problem you have, too. A few trapped earwigs may be nothing to worry about. More and you might want to try a chemical option to eradicate them. Read on.

One DIY solution is to fill a small cardboard box (like a Hamburger Helper or even a Jello box) with damp newspaper and a little oatmeal as bait. Punch holes around the outside of the box and install it flush with the soil in your flowerbed. After a day or two, remove the box and dump it in a bucket of water to kill the earwigs inside. Repeat. Roughing up a couple of plants around the trap is a good idea, too. Earwigs are attracted to damaged and decaying vegetation.

You can also leave a little oil or juice in the bottom of a tuna fish can and partially bury the can in the garden. The earwigs climb in and drown. Another take on this technique is to place a half-inch of oil in the bottom of a cat food or other shallow can. All will work for small infestations where you can eradicate earwigs in modest batches. I have also read that beer and soy sauce are attractants that can be used in traps.

There are commercial earwig traps on the market, too. Some work on multiple insect varieties, so read the labels to determine the best product for your needs.The nice thing about an outdoor trap, as opposed to a broadcast insecticide, is that beneficial insects won't be affected, or at least won't be decimated in large numbers.

For indoor problems, anything that will kill cockroaches will kill earwigs indoors.

Insecticides that Kill Earwigs

A mild insecticidal soap can be effective against earwigs, but may not be adequate to control large populations. Reapplication throughout the season will be necessary, too.

If you decide to use a stronger insecticide, products containing spinosad or carbaryl are considered the most effective. Make sure the delivery method includes heavy saturation of the soil, where earwigs spend most of their time when they're not actively eating garden plants. To protect beneficial insects like bees as much as possible, prefer spraying at night when other insects are less active.

Utilize Natural Predators

If you like the organic approach, earwigs have natural predators in the environment. Encouraging their presence can help keep earwigs under better control. The tradeoff here is that inviting earwig predators into your garden means having to tolerate them. If you don't mind a little wildlife, though, it's an elegant option. Here are some critters who think earwigs are a delicacy:

Two fly varieties attack earwigs. They are the Bigonicheta Spinipennisand the Digonichaeta Setipennis. Both are attracted to certain plants and especially herbs, like:

• Anise (Pimpinella anisum)
• Dill (Anethum graveolens)
• Fennel (Foeniculum vulgare)
• Tansy (Tanacetum vulgare).

Plant these herbs, and the flies will follow in manageable numbers (*in many areas of the country). Caution: Fly populations may increase where these plants are plentiful.

A number of frog and lizard species also eat earwigs. Attracting them may be challenging, but if you're game, some additional research may reveal ways you can attract indigenous frog and lizard species to your garden.

Numerous wild bird species like to eat earwigs, too. Adding bird feeders could net you some interesting bird antics and reduce the earwig populations on your property. Here are some birds that may be tempted to partake of a bug or 10 once they decide they like the menu at your house:

• Robins
• Crows
• Blackbirds
• Chickadees
• Nuthatches

There are probably many more, too.

Install a chicken coop. The chicken is one domesticated bird that enjoys an occasional earwig appetizer. If you've ever wanted homegrown eggs, now is the time to add a free range hen or two to your property (provided city ordinances allow it). I've heard that ducks also enjoy eating earwigs, but couldn't corroborate that. If you have more information, please let me know.

Use Other Controls

Apply diatomaceous earth to areas where you know earwigs are active. Diatoms are the fossilized remains of ancient sea creatures. In the garden, they act as mini-razor blades that discourage insects like earwigs, slugs, snails, millipedes and ants. Wear a respirator during application. Using diatoms can be a natural and pretty effective measure against a variety of pests. It's relatively safe, too. The bad news is you'll have to repeat the application process periodically, like after a heavy rain.

Boric acid is another option. It's a naturally occurring substance poisonous to many insects like earwigs and ants.

*Check with your local Cooperative Extension Office for information about the fly species, birds, frogs and lizards in your area. There's a reference link in the sidebar below.



Resources

LaLiberte. Kathy. "How to Attract Bug-Eating Birds." Gardener's Supply Company. http://www.gardeners.com/Attracting-Bug-Eating-Birds/8103,default,pg.html

Orkin Pest Control. "Earwigs." http://www.orkin.com/other/earwigs/

Sedbrook, Judy. "Earwigs." Colorado State University Cooperative Extension, Denver County
http://www.colostate.edu/Depts/CoopExt/4DMG/Pests/earwigs1.htm

U.C. Davis. "Earwigs." http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn74102.html

University of Florida. "European Earwig." http://entnemdept.ufl.edu/creatures/veg/european_earwig.htm

University of Maine Extension. "Fact Sheet - Earwigs." http://umaine.edu/ipm/ipddl/publications/5017e/Photo1 - Earwig1.jpg James Lindsey at Ecology of Commanster [CC-BY-SA-2.5 (http://creativecommons.org/licenses/by-sa/2.5) or CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons http://upload.wikimedia.org/wikipedia/commons/5/54/Forficula.auricularia.nymph.-.lindsey.jpg http://commons.wikimedia.org/wiki/File%3AForficula.auricularia.nymph.-.lindsey.jpg 
 Photo 2 - Earwig2.jpg By Pudding4brains (Own work) [Public domain], via Wikimedia Commons http://upload.wikimedia.org/wikipedia/commons/f/f0/Earwig_nest_-_Lonnekermeer20070411_04.jpg http://commons.wikimedia.org/wiki/File%3AEarwig_nest_-_Lonnekermeer20070411_04.jpg

Photo 3 - Earwig3.jpg By Menchi at en.wikipedia [GFDL (www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0/)], from Wikimedia Commons http://upload.wikimedia.org/wikipedia/commons/2/26/Earwig_on_tin.jpg http://commons.wikimedia.org/wiki/File%3AEarwig_on_tin.jpg