Larry Sagers Horticultural Specialist Utah State University Extension Service Thanksgiving Point Office © All Rights Reserved
For more information on night-feeding insect pests, read my article in yesterday’s Deseret Morning News.
Finding the right subject for a weekly gardening show is sometimes challenging. Sometimes deciding on the subject is a response to numerous questions about “What is wrong with my plants.” So with a slight apology to Mr. Shakespeare, the subject of this weeks column is “A Midsummer’s Night’s Insect Feeding Frenzy.”
The cast includes some of the worst garden pests in the state. They did not win their part because they were beautiful. In fact, some of these rouges are downright ugly.
One creature is the European earwig. They are a problem with many plants but will soon move into the apricots as they start to ripen. Later they are a problem in peaches particularly if they are damaged. Split pits in peaches are common when the weather turns hot early in the season. There is nothing to do about the split pits but you can try to keep the earwigs out of the fruit.
Earwigs are about 0.5 inch long, shiny brown, and have a pair of forcepslike structures at the back end of the abdomen. They are nocturnal and their presence or damage may go unnoticed until harvest. There are two generations per year.
Earwigs feed on fruit and foliage. Foliage feeding is of little concern in mature trees. However, shoot-tip feeding on young trees may stunt normal growth.. On young seedlings, earwigs can destroy the plants.
Cultural Control Remove weeds from around the base of trees. Keep orchard clear of prunings or other debris where earwigs could nest. Remove tree limbs that come in contact with soil to prevent alternate access to trees. M onitoring and Management Decisions Place boards or rolled-up newspapers in the orchard in early spring and monitor weekly for earwigs that hide under the boards or in newspapers. Treat at the beginning of spring activity when earwigs are found. The European earwig was introduced to the United States in the early part of this century and is now found in most parts of the country. In some places, it is found in extreme numbers, most likely due to lack of or a minimal number of natural enemies.
Earwigs overwinter as pairs of adults in subterranean cells. Females begin laying eggs in the early spring in earthen wells, under rocks, boards, etc. Males are found in the proximity of the nests, but are not allowed into the nest (males have bowed pincers, while females have straight pincers).
The female guards the eggs until they hatch (late April to early May). The female stays with the nymphs, leaving the nest at night with the nymphs to forage. The female eventually leaves the nest when the nymphs fail to return to the nest. In late June the female will then lay a second batch of eggs. During daylight hours earwigs hide out in secluded areas under debris, flowers, clusters of fruit, etc. At night they emerge to feed.
Earwigs are opportunists when it comes to eating. In some cases they serve as superb natural enemies, feeding on a range of insects. In codling moth infested apples, earwigs will follow tunnels created by codling moth larvae, locate and consume the larvae. But they will also feed on plants, brings them into conflict with gardeners.
Earwigs crawl up and down the tree and usually spend the night in the soil debris. If you keep them from crawling up the tree, they cannot bother the fruit.
Spray the trunks with Tanglefoot. This sticky material is the material they use to coat flypaper. It will trap the earwigs as they try to crawl back up to the top of the tree. Spraying them is usually not effective and you must observe all preharvest intervals.