Insect Pests: Earwigs

Earwig Damage on Basil

A mild winter and a warm spring resulted in a bumper crop of earwigs this year. Earwigs like cool, dark, damp places. Outdoors, earwigs are primarily nocturnal, so it may take a trip outside in the evening with a flashlight to confirm that the pest chewing on your plant leaves is indeed an earwig. During the day, earwigs may be hiding under leaf litter or in any cool crevice, including the siding of houses.

Unfortunately, earwigs are good mothers, which is why earwigs tend to appear in large groups:  most of the earwigs you see are siblings! The female typically gives birth to 40-55 eggs and continues to care for her offspring through the second molt. After laying her eggs below ground, the female covers the entrance to the nest with dirt, so finding the nest is unlikely. The nymphs, who physically resemble the adults, continue to return to the nest at night after feeding.

Most horticultural articles on earwigs refer to them as minor pests. Don’t believe it. Any insect that competes with you for the food you’re growing is a major pest, period. Secondly earwigs are difficult to safely eradicate on edible plants or plants with edible fruit or leaves. If earwigs were such a minor pest, those same articles wouldn’t need to reference Sevin, a nerve poison, as one of the more effective means of chemical control. The only truly safe insecticide for earwigs on plants is insecticidal soap. In order for the soap to be effective, it must be sprayed directly on the insect. (Insecticidal soap works by blocking the insect’s spiracles, small openings on the sides of the insect’s body that allow it to breathe.)

An oft-cited remedy for earwigs is to roll up a damp newspaper and place it near the affected crops. At night, after feeding, the earwigs will supposedly seek shelter in the newspaper. The following day, you dispose of the resting earwigs by placing the newspaper in a bucket of soapy water. Personally, I’m not a fan of any pest management plan that relies on attracting a pest to an area where I don’t want it. About 15 years ago, during a summer with major slug populations, I set out a dozen slug traps filled with beer. In the morning, all the Bud Light had disappeared, maybe one or two slugs drowned in the beer, and my plants continued to be ravaged.

Eradication of earwigs isn’t easy, but with a flashlight, insecticidal soap, and repeated nocturnal visits to the affected plants, you can begin to bring earwigs under control. For what it’s worth, I did notice that earwigs stayed away from my basil that was planted next to some dill. I’ve never seen dill mentioned as an earwig deterrent, but you may want to give it a try and see if it helps.

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One Response to Insect Pests: Earwigs

  1. I once had a terrible problem with earwigs , trying to grow vegetables in Australian. Found out they breathe through there skin and sprayed Amway L.O.C. on them . Hope this is of some help .

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