Problem: Codling Moth (Apple)
Cydia pomonella This worm, the larva of a 1/2-inch-wide gray-brown moth, is one of the most serious apple pests in the United States. The moths appear in the spring when the apple trees are blooming, usually flying at twilight. They lay their eggs on the leaves, twigs, and developing fruit. When the eggs hatch, the larvae tunnel into the fruit. They feed for several weeks, then emerge from the fruit, often leaving a mass of dark excrement on the skin and inside the fruit. After pupating in sheltered locations on or around the tree, another generation of moths emerges in midsummer. Apples may be damaged by worms continuously throughout the summer. In the fall, mature larvae spin cocoons in protected places such as under loose bark or in tree crevices. They spend the winter in these cocoons, emerging as moths in the spring. They may also overwinter on other plants under the trees.
Once worms have penetrated the apples, it is impossible to kill them. To protect uninfested apples, apply an insecticide labeled for this pest, following label directions. Remove and destroy all fallen apples and clean up debris. Pheromone traps can also be used to control codling moths. Hang at least two per tree.