How to Make an Earwig Trap for Your Vegetable Garden

You know those crawly critters with the pinchers on their tail end. If their looks aren’t enough to creep you out then the old wives’ tale about them crawling into your ear at night and burrowing into your brain should do it. Of course none of that is true! Darn those old wives! Earwigs are a common garden inhabitant and it seems like everything in the garden that I disturb or move, even just a little bit, usually has a few hiding under it.

Photo: This is a male earwing. They have the curved pinchers while the female’s are straighter.

Another Garden Mystery Solved

It took me a while to put 2 and 2 together and come up with earwigs as the problem when my rutabagas were under attack.

Every day more and more of the leaves were being eaten until they looked like tattered rags. Normally I would blame a caterpillar but since we grow most of the brassicas under a shade cloth tunnel to keep moths from laying eggs on them I had to rule that out.

This shade cloth tunnel has successfully thwarted many a cabbage moth from laying eggs on our brassicas.

Plus there weren’t any caterpillars to be found or their tell-tale droppings. Slugs were my second guess but it has been a dry year and I haven’t seen many slugs. Also there was no trace of the slime trail they leave behind. The damage is limited to just the rutabagas, even though they are planted next to broccoli and cabbage plants, those have not been touched at all. A puzzle. Then when harvesting bok choy from another part of the garden I noticed that those plants had similar damage.
The leaves on the last of the bok choy were ravaged by the earwigs and they left behind lots of droppings on the stems. It must have been quite a party!

When I shook them upside down after cutting them, several earwigs fell out. Aha! We have seen them in the past mostly on the dahlias and zinnia flowers but I was under the impression that they were actually beneficial in the garden. They are known to eat aphids and insect larvae but feed mostly on decaying plant matter.

Then I learned that the nymphs are the ones that do the most damage, eating holes in leaves of young plants while the adults are the ones eating the flowers. The teenage nymphs look very like the adults but their shells are softer and not as dark.

Both the adults and the nymphs feed at night, doing their dining under the cover of darkness and sleeping it off in a moist shady spot during the day. I decided to try and eradicate them from the rutabagas by trapping them. After searching thru several books and websites, I found 5 traps to try:

Testing Five Earwig Traps

Notice the holes around the rim of the container. Maybe I should have punched more of them?

• Trap #1 had me punch holes near the rim of a small plastic container, add some oil and a bit of soy sauce. Then I replaced the lid and buried the container with the holes level with the top of the soil. All it caught were ants—loads of tiny ants. Drawn by the promise of Chinese food I guess.

This trap was simple enough to make and did bag one earwig.

• Trap #2 was a toilet paper tube stuffed with straw placed among the plants under attack. A bit more successful. It caught 1 earwig.  

One culprit caught. How many hundreds more to go?

• Trap #3 was a can with leftover beer in it. (Honestly, who ever has leftover beer?) I thought at least it would catch a slug or two but it caught nothing, as slug do love beer. They probably didn’t like the cheap brand I bought.

No luck with this trap. Maybe they prefer the sports page.

• Trap #4 was crumpled damp newspaper stuffed into a flowerpot. I hung the flowerpot upside-down next to the rutabagas and again caught nothing. Maybe they had already read the comics from that day’s paper. 

Any fishy-smelling oil will do - tuna, sardines, or my favorite - smoked oysters.

• Trap # 5 was the “oil trap” which simply a small container baited with fishy-smelling oil in it. That was the most successful trap. It caught about a dozen earwigs in one night! 

You could also bait with canola oil. Some folks add bacon grease or hamburger fat as, apparently earwigs love greasy, oily stuff. But I didn’t have anything like that in the house. Plus, this could attract larger critters including raccoons and skunks so if your garden is not fenced to keep them out you might not want to risk it.

Another idea to test is to cover the container with a lid, with an entry hole cut in the lid, and then empty and refill every week or so. That way you only catch earwigs (no other insect is interested in the oil trap).

I assume that the heavy amount of mulch we use in the garden is contributing to the rise in the earwig population. Next spring I might wait and use a straw mulch later in the season after the nymphs have matured. The earwigs have stopped feeding and my rutabagas seem to be recovering. Next year I will try to be more observant and take action sooner if the plants are under attack again because I do love my rutabagas!

See the Almanac’s article for more information on how to identify, prevent, and get rid of earwigs.