Earwigs are omnivores. They eat a variety of things, including other insects, parts of plants, decaying matter, and some fruits and vegetables such as peaches, apricots, or the silk at the top of corn. If you have an earwig infestation in your fruit trees or corn patch, there’s a pretty simple way to get rid of them at very little cost to you.
Earwigs like areas that are cool, moist, and dark. They often hide under logs or leaf litter on a forest floor where those conditions commonly exist. If you can create a nice moist, dark environment the earwigs will gather there and once the earwigs are all together in one spot they are easy to eradicate. (Pictured below is a male earwig – males have curved pincers, female’s are generally straighter.)
Put pieces of newspaper, cardboard, or even old strips of carpet around the base of your fruit tree. If you use old carpet lay it fuzzy side down. Sprinkle your ‘trap’ material with water, and wait. After several hours, or up to a couple of days, the earwigs will come down the tree and crawl under your wet cardboard or carpet and hide out there during the day. They’ll love the new little home you’ve made for them. Lift up the carpet or cardboard and kill the assembled earwigs by stepping on them or some other way – you choose your method. You might be tempted to just let them be; after all, they’re on the ground and not in your fruit anymore. This is a mistake because after a while they will get hungry again and go back up your tree and feed on your fruit, generally at night time, when earwigs are more active.
A couple of other things to note: old carpet is probably the best trap material because it holds moisture the best and it won’t fall apart when you try to lift it up to get the earwigs. Cardboard, and especially newspaper, are more flimsy particularly when wet. Also, you don’t have to hug the base of you tree with the trap material like a collar around the trunk; simply place the material loosely around the tree. Don’t drench the trap material – just keep it moist; the earwigs must be able to breath under there. If you live in hot and dry climates, you may have to sprinkle the trap material every few hours so it remains moist.
Earwigs have proven to be a pretty good biocontrol for herbivorous insects (such as aphids) that do damage to plants. But since they are omnivorous themselves, they sometimes damage plants themselves, so I would not recommend trying to use them as a biocontrol.