Codling Moth Location
The codling moth, or apple worm, came to this country from Europe about 1750 and quickly became our most destructive pest of apple fruit.
Codling moths also attack pears, apricots, cherries, peaches, plums, quinces, crabapples and, in California, English walnuts. Unfortunately, spraying with pesticides is often the only effective method of controlling the codling moth, which is why these fruits are the most highly-contaminated with pesticides. (http://www.foodnews.org/reportcard.php)
Codling Moth Appearance and Habits
The insect passes the winter as a full-grown larva, an inch-long pinkish-white caterpillar with a brown head, inside a silken cocoon under loose scales on apple bark or in other sheltered places. In spring the worms change to brown pupae and then grayish-brown moths, 3/4 in. across the wings. These emerge to lay their eggs, singly, on the upper surface of leaves, on twigs and on fruit spurs. They work at dusk, when the weather is dry and the temperature is above 55° F.
A cold, wet spring at the time of egg-laying means less trouble with wormy apples. Hatching in 6 to 20 days, small worms crawl to the young apples, entering by way of the calyx cup at the blossom end. They tunnel to the core, often eating the seeds, then burrow out through the side of the apple, leaving a mass of brown excrement behind, and crawl to the tree trunk to pupate. There are two generations over most of the United States, and in some places a partial third. Second-brood larvae enter the fruit at any point, without preference for the blossom end.
Crop reduction comes not only from wormy fruit but from early drop of immature apples and from “stings” – small holes surrounded by dead tissue which lower fruit value even though the worms are poisoned before doing further damage.
How to Manage Codling Moths
Plant cover crops that support moth-eating beetles.
Hand-remove and destroy larvae.
Band trees with parasitic nematodes.
Clean up the orchard by scraping loose bark from trees and removing rubbish and all dropped apples immediately.