Earwig

• Ragged, irregular holes in seedling leaves, flower petals, and soft vegetable tissue — often overnight
• Damage resembles slug injury but without slime trails
• Flower petals on dahlias, marigolds, and lettuce heads riddled with small holes by morning
• Seedlings clipped at or near the soil line in moist, sheltered beds
• Earwigs visible under boards, dense mulch, or pots when you lift them at night or in the morning
• Corn silk chewed and silk channels damaged, reducing pollination

European earwigs are nocturnal. Females lay 20–80 eggs in a shallow soil cavity in late winter and guard them — unusual parental behavior for insects. Nymphs hatch in spring and go through four molts before reaching adulthood by early summer. Adults and nymphs both feed on living plant tissue, decaying organic matter, and other small insects including aphids and mites. This mixed diet makes earwigs genuinely ambiguous: in a garden with a moderate aphid load, earwigs can provide measurable pest suppression; in a seedling bed or cutting garden, they can cause significant cosmetic and structural damage.

1. 01Reduce hiding spots near vulnerable plants: pull mulch back from seedling stems and avoid dense debris near transplants
2. 02Set rolled damp newspaper or a short length of garden hose near damaged plants in the evening — earwigs shelter inside by morning and can be shaken into soapy water
3. 03Trap under a board or cardboard square laid near damage sites; collect and dispose of earwigs each morning
4. 04Apply a thin layer of diatomaceous earth around seedling stems in dry conditions — it loses effectiveness when wet
5. 05In seedling areas where damage is severe, consider spinosad-based baits labeled for earwigs
6. 06In beds where aphid pressure is present, tolerate low earwig populations — they may be doing useful work

If you're seeing severe seedling losses and can't confirm earwigs as the cause (vs. cutworms or slugs), a local extension office can help distinguish the culprit from the damage pattern.

• Earwigs— UC ANR Integrated Pest Management
• Earwig Management in Gardens— Oregon State University Extension