“Oh no, what ate my pepper plants? I don’t see anything,” a caller said. Earwigs seem to have taken over the world, eating everything in sight. Earwigs look alarming with pincers at their hind end, and they bother even seasoned gardeners who normally have an attitude of “live-and-let-live.”
The most common earwig problems gardeners notice are damage to developing seedlings and flowers, earwigs coming out of ripening fruit, or earwigs scurrying away from compost or piles of garden litter. In northern Nevada, the most prevalent is the European earwig, which is primarily a garden dweller. Earwigs are nocturnal, preferring damp cool places in crevices, under bark and in garden debris. They will eat almost anything, including other insects. They eat dead and dying plants, soft fruits like strawberries and stone fruits, petals, pollen and seedlings. Their eating of the silks on corn plants can cause poor kernel development. Typical earwig damage on most plants is small holes in the margins of leaves. Whole seedlings may disappear. They chew shallow gouges or holes in fruit.
To manage these critters that are normally beneficial predators of mites and insects, first go outside at night with a flashlight and identify what is eating your plants. If earwigs are the culprits, use compost or chipped bark to provide a complex soil surface with many organisms on which the earwigs can feed. If your yard is well mulched, and earwigs are chewing on garden seedlings, raise seedlings indoors and transplant them outside when they are large enough to withstand damage or cover them with row covers.
Earwigs are easy to trap. Place low cans with ½ inch of vegetable oil in among your plants. Dampened rolled up newspapers or pieces of hose also make good traps because earwigs like dark moist places. A clay or plastic pot filled with damp sphagnum moss and placed upside down with a small opening provides an inviting earwig abode. Place the traps near the plants just before dark. Check the trap the following morning and shake the trapped insects into a bucket of soapy water to drown them. Reset traps daily in order to reduce the earwig population.
Diatomaceous earth works well as a barrier around plants. Remove boards and rubbish from areas with large populations of earwigs to eliminate hiding places. Some chemical products are labeled for earwig control, such as pyrethrin products, although insecticides are rarely needed. Insecticidal soaps are labeled for earwig control as a contact insecticide.