Earwigs: Nature’s Scavenger
Photo: https://hort.extension.wisc.edu/articles/earwigs/
It is a rare gardener who has not seen an earwig in the landscape. These formidable-looking insects are beneficial in most cases, are not a danger to humans, and provide a valuable service to the landscape. Despite rumors to the contrary, they do not crawl into the ears of sleeping individuals to cause fevers and insanity.
Earwigs were first recorded on the east coast in 1912 and on the west coast in 1907, but didn’t make it to Wisconsin until about 25 years ago. Over 20 species exist, but only one in Wisconsin: the European Earwig (Forficula auricularia).
Earwigs are about 5/8 inch long with very short wings that they seldom use, instead choosing to travel about on legs or by hitchhiking on things that man transports like flowers, newspapers, tools, boxes, etc. Earwigs are an elongated, flat, brownish red insect with intimidating looking pinchers or forceps on one end. These pinchers are used to protect themselves and to hold onto prey. Rarely do they ever pinch humans and if they do, they cannot pinch with any great force. Instead, if provoked, they release a foul odor from their abdomen to deter further interaction.
Earwigs reproduce by incomplete metamorphosis, meaning that the young look very similar to adults. Young will be smaller, lack wings, be a lighter color, and have straight rather than curved pinchers. They emerge in the spring from a nest of 50-90 eggs that the female laid in the ground in the fall. This nest can be as deep as six feet underground to escape the cold weather as the adult insects hibernate during the winter. The young mature into adults by late August into October at which time they begin to enter their nest to repeat the reproduction cycle.
Earwigs are scavengers and will eat both plants and small insects. They are great at cleaning up small pest insects and decaying matter in the garden. However, their indiscriminate appetite also includes marigolds, dahlias, zinnias, hostas, lettuce, celery, potatoes, vegetable seedlings, and the silk on sweet corn. This does not endear them to most gardeners. The damage they inflict can look like slugs feeding, but slugs leave a slime train and earwigs do not. Most mature plants can tolerate some damage, but when earwig populations get too large, it becomes a problem.
The first step would be to attempt some cultural control. Earwigs prefer a dark, moist environment. Mulch, particularly on a southern side of a home, is an ideal place for earwigs to reside. Any leaf pile, plant debris, piles of bricks, boards, or other ideal hiding places should be removed. Make sure any leaking downspouts or air conditioners are repaired so that there is not a constant source of moisture. When watering the gardens, water less frequently, but deeply to reduce the surface moisture.
If earwigs persist, trapping and removing them is a relatively easy process. Earwigs are nocturnal feeders. Therefore, set out rolled up newspapers, cardboard tubes, rolled up corrugated cardboard, or a small box with ¼ inch holes punched along the sides near the bottom. In the mornings, simply pick up the trap and shake it into a pail of soapy water to drown the earwigs. Persistence is the key to reducing the populations of these beneficial, but sometimes pesky insects.
Happy Gardening.
Carol Shirk
Certified Master Gardener