Codling moth is the most important insect pest of apple and pears in North America. Damage is done by the larvae, which are cream-colored caterpillars that tunnel fruit and produce ‘wormy’ apples (Figure 1).

The development of codling moth, like all insects, can be predicted based on accumulated heat over time, called degree days (DD). Use of the codling moth phenology model based on DD will help to …

Guidelines for control of the codling moth are in the annually revised New England Apple Pest Management Guide and other publications of UNH Cooperative Extension.

It explains the use of degree day models. The Utah publication does list specific products that can be used as sprays to control codling moth. For backyard trees, check the “Residential” column. …

Codling moth development is greatly influenced by temperature; these insects will develop more quickly in a warm year and more slowly when temperatures are cooler.

Written by Ellie Andrews, UCCE Specialty Crops Advisor, March 2025. All photos are from the UC IPM website except for the photo of the codling moth on a trap, which was taken by Ellie Andrews.

Codling moths spend the winter in the worm stage in cocoons that they spin under bark scales on tree trunks, under other shelter about the base of trees, on the ground, or in picking boxes that are stored …