By Laura Jesse
Plant and Insect Diagnostic Clinic
Iowa State University Extension
Earwigs are easy to recognize by the prominent pincers or forceps on the end of the abdomen. Adults are about 5/8 inch long and dark brown with a reddish head and pale yellow-brown legs.
If samples and questions to the ISU Plant and Insect Diagnostic Clinic are a measure of how well an insect is doing, I would guess that earwigs are doing very well. They seem to have gone from an insect seldom seen to one that many people encounter regularly in their yards and sometimes houses.
For some reason people are not too fond of earwigs, possibly because earwigs are the insect reputed in superstition to purposefully crawl into the ears of sleeping persons for the purpose of burrowing into the brain to lay eggs. Of course, there is no truth to these tales, though earwigs, like moths, beetles, cockroaches, ants and flies may wander into our ear canals by accident.
You should know though that earwigs are unique in that they provide some parental care of their young. Earwig nests are a short tunnel in the soil, usually next to a rock or other object. The female earwig lays her eggs and then spends all her time with them to prevent mold from killing them. She eats the mold off of her eggs to keep them clean. Somehow this makes me feel like all those months changing dirty diapers were not that bad.
Earwigs live outdoors and hide during the day in damp areas such as under mulch, dead leaves, logs, and piles of firewood, boards, stones and other debris or in rotted wood. I also see them a lot hiding in flowers and in plants that provide some protection, little the top of milkweed plants were the leaves are folded together. Earwigs are active at night and wander in search of food and moisture. Earwigs feed on a wide variety of materials including decaying organic matter, other insects, and plants such as vegetables, flowers and ornamental plants.
Like boxelder bugs, crickets and lady beetles, the earwig is a household pest as an accidental invader. They enter houses either by accident or when seeking shelter, especially in the fall or during periods of prolonged dry weather. Earwigs inside the house do not cause any harm or destruction. They are an annoyance or nuisance because of their presence. If disturbed, earwigs may produce a noticeable foul odor.
Earwigs found inside the house can be swept or picked up and discarded. Indoor treatment with household residual insecticides such as for cockroaches could be used in cracks and crevices that serve as points of entry, and along baseboards, window sills and door thresholds. Such treatments may provide limited benefit as more earwigs may wander in from outdoors. In addition eliminate damp, moist conditions near the house as much as possible. Repair dripping faucets and air-conditioning units and channel water from rain gutters and spouts away from the house foundation. Remove landscape mulch and debris (wood chips, gravel, old boards and bricks, etc.) from against the house and in areas of high numbers.
Outdoors earwigs can cause damage to plants and it is particularly annoying when they feed on the flowers. Management of earwigs is not easy and there is probably no way to completely eliminate them from your yard.
Consider trapping and physically destroying earwigs. Place burlap bags, boards, newspapers or other materials on the ground, then daily collect individuals that congregate under the cover and discard.
As a last resort insecticides can be sprayed on plants to reduce damage. Select a home garden labeled for this purpose and apply according to label directions. Avoid applying insecticides to flowers because you will harm beneficial pollinating insects. Applications in late afternoon are preferred since earwigs feed at night.
Just remember each earwig has a mom out there somewhere who ate mold off them when they were little eggs.
Laura Jesse, Plant and Insect Diagnostic Clinic, (515) 294-5374, firstname.lastname@example.org
Two high resolution photos are available for use with this column.
MaleEarwig.jpg [200 kb] is a closeup of an adult male earwig.
earwigondaylily.jpg [472 kb] is a closeup of a daylily flower that has been damaged by an earwig.