Appearance

Adult moths are about nine to 12 mm long, and their wings are gray in color with indistinct dark / light wavy lines that are bronzed-colored at the tips.

Click here for enlarged images of the appearance of an adult codling moth.

Mature larvae are about 13 mm long, pinkish-white in color, and have a brown head.

Click here for enlarged images of the appearance of a codling moth larvae.

Adults begin to emerge around the bloom or petal-fall stage of apple. Throughout the season, the codling moth is most active immediately before and after sunset. However, seasonal data from sticky traps baited with sex pheromone lures indicate that males are still somewhat responsive through midnight and show some level of activity during the early morning (sunrise) hours. During the day and at other inactive times, adults rest on the branches and trunks.

Mating usually begins at evening twilight and occurs in the upper portions of the trees. The female will usually start laying eggs within 48 hours of mating. Eggs are laid primarily on leaf surfaces near the fruit. After egg hatch, the larvae begin to feed on the fruit. After feeding, they leave the apple and seek out a protective site to pupate. During the warm summer months, the developmental time from egg to adult is about six weeks. The codling moth over-winters as a mature larva in a dense silken cocoon found under loose bark or in debris beneath a tree. They have also been found over-wintering in picking crates left in the orchard, bins holding culled fruit, and other protected sites around packing sheds.

The number of generations per year ranges from one to four, depending mainly on climatic conditions. In the northern states of the Midwest, there are two to three generations per year; in Missouri there are three generations. In Oregon and Washington, there are two full generations and a partial third generation each year.

Symptoms and Damage

After egg hatch, the larva bores into the fruit and begins chewing it’s way to the core, pushing its waste material (frass) out the entrance and/or exit holes. This type of damage is often referred to as deep entries. Sometimes a larva will bore into the fruit a short distance and then either die or move to another location to feed, leaving shallow entries called stings. Small amounts of frass may or may not be present at sting sites.