Earwigs will eat holes in the flowers and leaves of ornamental plants, but if you find an earwig curled up inside a hole in a damaged strawberry or flower blossom, don't assume the earwig is responsible. It may have just curled up in the convenient hole because it wanted a sheltered, moist place to hide from the heat and light of the day. The only way to be sure earwigs are causing problems is to go out at night with a flashlight and examine the plants. You may discover that the damage was caused by weevils, caterpillars, or snails and slugs because the symptom of the earwig is about the same as for those other critters. They chew out numerous, small, irregular holes leaving the leaves with a ragged appearance. However, they don’t leave behind a telltale slime trail as do slugs.
Earwigs only do significant damage to plants when present in large numbers. Some favored plants include clover, dahlias, zinnias, marigolds, butterfly bush, hostas, hollyhock, lettuce, strawberry, celery, potatoes, roses, seedling beans and beets, and tender grass shoots and roots. The population will fluctuate greatly from year to year depending mostly on the weather. Warm wet springs often lead to a healthy earwig population.
Earwigs can enter homes or buildings through the tiniest of cracks. Adults tend to aggregate at sites. Homeowners may suddenly discover a population in their basement, garage, or other structure.
Earwigs prefer high-moisture conditions. They will migrate indoors during periods of prolonged heat or drought to seek cool, moist hiding places. During the winter, they burrow into the ground or seek shelter deep in leaf litter or beneath structures on the ground. They forage at night, and sometimes large congregations of earwigs can be seen under a strong light.