Found throughout North America, these omnivores eat decaying organic matter such as mulch or compost. They are beneficial in that they eat aphids, mites, and nematodes. However, they also eat ornamental and vegetable plants, particularly dahlias, zinnias, butterfly bush, hollyhocks, lettuce, strawberries, potatoes, roses, and seedling beans and beets, as well as the silk of sweet corn. Usually the damage is minor, unless their populations are high. Earwigs hide in cool, moist places during the day and feed at night. They are unusual among insects in that the female fusses over her eggs and nymphs, and uses her pincers to protect them. Adults overwinter in the soil.
Earwig damage mimics damage from caterpillars and slugs; be sure you've identified the real culprits by looking for feeding earwigs on your plants after dark. Make traps from rolled-up newspapers or cardboard filled with straw and taped shut at one end. Place them near plants and dump the contents into a bucket of soapy water in the morning. Or fill cat food cans with 1/4 inch of oil (preferably fish oil) and sink them into the ground near plants. Empty them every day. Sprinkle a 2-inch-wide circle of diatomaceous earth around beds or the base of plants; reapply after rains. Place a light-colored cloth beneath an infested plant and shake or tap the branches. The earwigs should fall onto the cloth and can be disposed of. The earwig's only insect predator in North America is the tachinid fly. Attract this fly by planting alyssum, calendula, dill, and fennel.
Continue reading for more information.