They appear formidable with their armor-like exoskeleton and sharp-looking pincers. Nevertheless, earwigs are little more than a nuisance for most homes and gardens.
"The name earwig literally means 'ear creature,'" says Steven Jacobs, extension entomologist in Penn State's College of Agricultural Sciences.
"The name originated from the widespread superstition that these insects will enter your ear and bore into your brain while you're sleeping," he says. "In fact, the last place an earwig would want to hide is in a person's ear."
There are 22 species of earwigs in the United States, about five of which are known to invade homes. The most common species in Pennsylvania is the European earwig.
Adult European earwigs are about five-eighths of an inch in length and dark reddish-brown. Their most distinguishing physical feature is the claw-like forceps on the end of their abdomen, which are used for protection or capturing prey. "The forceps are straight-sided on most females, but more curved or pincer-like on males," Jacobs says.
Earwigs are active at night and hide during the day in dark, moist places such as cracks and crevices, and under boards and decaying tree bark. They lay eggs underground, and adults can survive the winter. These insects rarely fly and often are transported by humans in bundles of newspaper, luggage, cut flowers, cars and other objects.
Earwigs are mainly scavengers and feed on a variety of foodstuffs. They eat almost any plant material, as well as lichens, pollen, other insects, and most household pantry items, such as flour, bread and cookies.
Although earwig damage to garden and agricultural plants usually is minimal, these insects sometimes seek shelter in and around homes, becoming a serious nuisance. High populations of earwigs often coincide with periods of warm and humid weather.
"When earwigs invade homes, they can get into everything, including laundry, furniture, loaves of bread and even clothing and bedding," says Jacobs. "They hide in cracks and crevices and are difficult to keep out, even with screens and other barriers."
Jacobs says the first step for controlling earwigs is to eliminate breeding and nesting places. "Remove decaying vegetative matter around your home, such as piles of leaves or grass clippings," he advises. "Repair poorly placed downspouts and broken irrigation systems that may create moist, dark areas attractive to nesting females."
European earwig populations also may be reduced by using grooved-board traps around shrubs, hedges and trees. Traps should be checked at least twice weekly, and any earwigs found should be shaken into a can containing a small amount of oil.
As a last resort, baits or insecticides can be used to kill earwigs and maintain a barrier around the outside of your home. But Jacobs urges caution when using chemicals. "Before using pesticides, read and follow all directions and safety precautions on the label," he says.
Single copies of the earwig control fact sheet are available free of charge by contacting your county Penn State Cooperative Extension office or by calling the Department of Entomology at (814) 865-1896.
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