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. Overwintering adults lay clusters of round, white eggs in the soil in late winter; larvae, which resemble adults, hatch in spring. Adults overwinter under garden debris, stones, and boards as well as in 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. Clean up garden debris and organic mulches, especially around foundations, since moist areas serve as daytime hiding spots for earwigs. Spread dry gravel as mulch next to foundations. Earwigs are attracted to lights, so eliminate or reduce lighting around foundations. To trap earwigs, set out crumpled, damp newspaper, lengths of old hose, or boxes with small holes cut in the sides and baited with oatmeal; collect and dump trapped pests in soapy water. Spread diatomaceous earth in limited areas where earwigs commonly travel, and repeat applications after rains; encourage tachinid flies, which are natural predators; apply the nematode Steinernema carpocapsae.
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 ¼ 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.