Don't Get Wigged Out by Earwigs
LOGAN, UT -- Answer by: Taun Beddes, Utah State University Extension horticulturist
European earwigs are commonly encountered insects in Utah and are recognized by the large pincers at the end of the body. The ideas that earwigs crawl into ears and that the pincers are dangerous are both false.
Earwigs are active at night and often go unnoticed; however, holes chewed in leaves can indicate their presence. If you suspect that earwigs may be eating your plants, examine the plants at night with a flashlight. Earwigs can be beneficial, acting as decomposers and predators of insect pests such as aphids and scales. However, they also feed on many vegetables, leafy greens, flowers and a wide variety of fruit. Since they spend the winter as adults, they can also become an indoor nuisance pest. Consider these tips for ridding your home and yard of earwigs.
• Homemade traps are inexpensive and can reduce earwig numbers in localized areas. One type is made from corrugated cardboard. Cut a 6-inch wide strip of cardboard and roll until it reaches about 4 or 5 inches in diameter. Tie the roll with string to keep it intact, then tie the bundle to the lower trunk of a tree. Collect the cardboard traps every two or three days, seal the earwigs inside a bag and throw them away. Rubbing the cardboard with fish oil or bacon grease can make the trap more effective.
• Another type of trap is an old sour cream, cottage cheese or margarine container with smelly oil, such as fish oil or bacon grease, poured into the bottom of the container. Bury the container in the ground almost to soil level, and cut a small hole in the in the lid for the earwigs to enter. The containers can be collected every few days and reused after the earwigs are dumped into a bag and sealed.
• Commercial, non-chemical control products are widely available, such as diatomaceous earth. This product is not harmful to pets or humans, but works by cutting or absorbing the thin waxy layer that covers insects. Sprinkle it around the base of plants that earwigs and other soft-bodied insect pests, such as aphids, scales and caterpillars, are damaging. Be aware that once diatomaceous earth contacts water, it becomes ineffective. It must be reapplied after rain or watering. To keep earwigs out of fruit trees, try wrapping sticky traps, such as Tangle Guard, around the tree trunk.
• Occasionally, it may become necessary to spray an insecticide to effectively control earwigs. Organic and reduced-risk products are available. Among these are pyrethrins and spinosad. Pyrethrins are derived from a species of chrysanthemum and control many insects. Spinosad is derived from a bacterium harmful to many insects but not mammals. Both are often labeled for use on many vegetables and fruits. Other chemical sprays are effective, but may harm natural enemies of earwigs and other beneficial insects. Of these available to homeowners, carbaryl (Sevin), malathion and permethrin are very common. Using non-chemical methods before resorting to sprays is recommend in most non-commercial situations. For more information, download the USU fact sheet about earwigs at: USU Digital Commons.
Ryan Davis, USU Plant Pest Diagnostic Lab insect diagnostician, made contributions to this column.
By: Taun Beddes - Jun. 7, 2012