Control Earwig Damage in Your Vegetable Garden
Earwigs hold a unique position with being both a helper and a pest in your garden. When earwig populations are kept in check, these bugs can be beneficial by eating other harmful pests such as aphids and slugs. However, earwigs are fast breeders and with the right conditions can quickly multiply to a point where they start looking for other forms of food, such as your favorite tender plants and new starts. When populations are out of control, earwigs can easily wipe out a bed of seedlings in a few nights. In order to protect your garden, there are a few steps you should take in early spring and throughout the growing season to keep earwigs under control.
The photo above is a real picture of my home garden. After weeks of putting out homemade slug traps and checking all sides of my plant leaves for other pests on a daily basis, I was stumped. It was hard to believe anything unseen could do this much damage to my bean plants seemingly overnight. New starts were disappearing days after emerging from the ground, and even the starts on my patio table were showing signs of serious damage. One night I got my flashlight out and wandered into the garden to find hundreds of earwigs on every row of vegetable starts and in every raised bed. I had found the culprit.
Earwig damage can look similar to slug damage. Earwigs tend to prefer the more tender parts of plants and will target young plants first, often leaving the tougher veins of the leaf alone. Because earwigs feed at night like slugs, you'll need to go out with a flashlight at night to be sure that's what you're dealing with. Luckily, they don't hide well at night and are easy to spot.
Oil traps are by far the fastest and most effective way to kill earwigs. As you can see in the picture from my garden below, oil traps can attract and kill hundreds of earwigs in a single night. This is one of four traps that were placed out with each containing hundreds of earwigs by the morning for the first week of use.
The process is simple and inexpensive. Take a used tuna can (I didn't even wash mine out that well, which may or may not have helped) and pour just enough olive oil in to coat the bottom of the can. At first, place oil traps on the outside edges of your garden so that you don't attract additional earwigs to your plants. Once you're only catching 10 or 20 earwigs each night, start moving your cans to where you continue to see plant damage. Some people bury the trap up to the sides to make it flat with the ground, but I found placing it anywhere on the surface of the soil works just fine.
Be sure to clean out the trap each day, I used a plastic fork, and reset for the next night. Change the oil periodically until you no longer catch earwigs. This is especially effective in the spring right after earwig eggs have hatched and before your first seedlings start to poke through the soil.
Paper Towel Traps
With earwigs living a nocturnal lifestyle, they are drawn to dark cool places during the day. To take advantage of this behavior, place out paper towel rolls or rolled up newspaper in areas around your garden. Cut up pieces of old garden hose also work well. Leave them out overnight and as the sun rises in the morning, earwigs will seek shelter in your traps. Simply shake them out into a bucket or into your oil trap for quick dispersal. Earwigs especially like shady, damp areas of soil but can be caught in almost any area of your garden.
Use DE Sparingly
Food-grade diatomaceous earth, or DE, is a non-toxic way to combat many pests in your garden, including earwigs. Apply a liberal amount of DE directly around the base of impacted plants so that earwigs will have to crawl through it to get to the plant stem. I also use DE around pots and other hiding areas where earwigs seek refuge. DE works by getting under the shell, or carapace, of the bug creating microscopic cuts in the skin. These cuts eventually cause the earwig to dehydrate to death. Because DE is a non-discriminatory killer, avoid using near blooms or on areas where bees or beneficial insects like ladybugs are active.
Sometimes the best method of removal is simply squashing them on the leaves of your plants with your fingers or knocking them into a can of oil if you can't stomach touching them. Use gloves while performing this task. Once it's been dark for an hour, use a flashlight to locate the earwigs. While you can find a lot of them easily on the top sides of leaves, make sure and check the stems and undersides as well. Usually, the earwigs won't run until they sense movement in the leaf, so make sure you get them on the first try or they will let go of the leaf and drop to the soil quickly and disappear.