Earwig invasion! Pest inundating gardens eats your fruit -- and those nasty aphids too


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If you’ve noticed more damage than usual to bean seedlings, lettuce or strawberries this spring, don’t automatically blame snails or aphids. Those ragged holes in leaves or tiny holes gored into fruit could be the work of earwigs.

Earwigs are everywhere this year, or so it seems. The bugs love moisture, and now that their favorite spots are starting to dry out after a wet spring, Southern Californians are seeing more of them around the house and in the garden. But are earwigs the cause of early damage to that fresh crop of edibles coming up?


It’s easy enough to find out: Bury containers at soil level near the affected plants, and fill the containers halfway with beer or vegetable oil. Or roll a few sheets of newspaper into tubes and place them around the yard, especially near lettuces. The next morning, shake the tubes over a pail. If what spills out is reminiscent of the aliens in ‘Starship Troopers’ -- scurrying, brown-black insect with a pair of wicked-looking pincers at the back end -- congratulations! You’ve got earwigs.Generally considered a pest, earwigs are omnivorous, eating other bugs (including those dreaded aphids and mites) as well as the greens you’ve so carefully cultivated (European style, salad after the main meal).

If you’ve got an apple tree, the earwig is a beneficial insect that helps control aphids. It also chomps through decaying foliage, helping to enrich soil.

But for others, its presence is decidedly less welcome. Earwigs go for lettuce, roses, strawberries, ripe peaches and plums, zinnias, dahlias -- most new seedlings, actually.

They are often found near foundations, pipe connections, compost piles, sinks, lawn furniture, under the bark of trees, in the thistle of artichokes — any space that’s tight, moist and dark during the day.

Programs to control the two main local species were abandoned in 1952 when colonies were found to be so ubiquitous throughout the L.A. Basin that eradication was considered impossible. The ring-legged earwig is smaller, prefers an insect diet and is less of a pest than its relative, the larger European earwig.

The easiest way to prevent a population explosion is to remove places where earwigs find shelter and to lay out traps. Their enemies are preying mantids and assassin bugs. They also can be deterred with citrus oil or botanical oils, but use either with caution. If earwigs are crawling up trees, use a sticky tape or some other insect barrier such as Tanglefoot.


-- Jeff Spurrier

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