The codling moth larva is a very destructive pest of apple, pear and peach fruit. This is the ‘worm in the apple’.
There are 3 generations per year that require management in commercial orchards in Kentucky.
Identification and Biology
The larva is pinkish with a brown head and can reach 3/4 inch. Pupation occurs in spring about the same time
as bloom with adults emerging in late April or early May. The adult is about 3/8 inch (10mm), gray, with distinctive
bronze areas on the bottom 1/3 of the wing.
Adult codling moths showing coloration at tip of wings, even when captured in a sticky trap. The larva on the right is pinkish in color.
Control of codling moth in commercial orchards relies on regular scouting of the trees and fruit, pheromone
trapping, and the use of weather monitoring and degree day models. Traps should be monitored twice a week early
in the season and on a weekly basis starting in mid May.
Pheromone trapping uses chemical lures to attract male moths. A trap consists of plastic top and bottom
held together by a wire hanger with the lure placed inside (1C or 1CP trap). Traps are hung in the southeast
part of the tree at eye level, usually 1 for each 10 acres (minimum of 2/orchard) in commercial orchards. Traps
should be hung pre-bloom with lures replaced monthly.
Degree Day Accumulation
Initial trap catch in the early spring is termed the biofix. The biofix for codling moth is the starting
date of the first sustained flight of moths. Generally, this is when the 5th moth has been captured. After
the biofix, degree days are calculated daily and compared with the target values in the following table.
Degree day targets for the various codling moth insecticides
DD target for application
Throughout the growing season in commercial orchards, trap catches that exceed
an average of five moths per trap per week trigger an insecticide application once
the number of degree days have been reached for the chosen insecticide.