Codling moth, Cydia pomonella, is one of the most serious insect pests of apple in the United States.
Biology and Life History
Adult moths are approximately 10 mm (⅜”) in length, with a wing span of 18 mm (¾”). Wings are mottled gray with a distinctive copper-colored band at the tip of each forewing (Figure 1).
Female moths lay flat, oval eggs singly on developing fruit or adjacent leaves. Newly hatched larvae enter fruit, usually through the calyx or sides, and tunnel into the core where they feed on the seeds and surrounding flesh (Figure 2). Larvae are white to pinkish in color with a brown head, and are about 18 mm (¾”) long when fully grown. Larvae will spend three to five weeks feeding within fruit before exiting to pupate. Brown frass (or excrement) extruding from entry or exit holes is a common sign of infestation (Figure 3).
Figure 1. Adult codling moth, Cydia pomonella. Photo courtesy of Clemson University - USDA Cooperative Extension Slide Series, Bugwood.org
Figure 2. Larva and associated damage on apple. Photo courtesy of Whitney Cranshaw, Colorado State University, Bugwood.org
Figure 3. Damage to an apple caused by codling moth (Cydia pomonella) larvae. Photo courtesy of Eugene E. Nelson, Bugwood.org
There are multiple generations of codling moth each year; typically two to three depending on summer temperatures. They overwinter as fully grown larvae within silken cocoons, usually located under loose bark or other protected locations near the base of trees.
Pheromone traps can be used to detect the presence of codling moth in orchards and monitor adult flight activity. In commercial orchards, the capture of moths in traps is used to help time insecticide sprays using a degree day based model.
Sanitation: Home orchardists should promptly remove infested fruit from trees as well as pick up any fallen fruit from the ground. These fruit should be destroyed to prevent any potential larvae within from completing development and continuing the next generation.
Bagging Fruit: Enclosing developing fruit within bags on the tree can provide protection from codling moth. Bagging should occur shortly after petal fall when fruit are approximately 18 mm (¾”) in diameter. Although paper bags or plastic sandwich bags have been used effectively for this purpose, double-layer Japanese apple bags have been specifically designed for bagging fruit.
Insecticides: Several insecticide options are available for codling moth control in apple. Please consult your local production manual for recommendations suitable to your area and needs.