Department of Entomology

Southeastern Apple Production ENTOMOLOGY

Codling Moth

Cydia pomonella

Description

The codling moth (CM) adult is about 1/2 inch long and has gray striped wings with brown patches at the base. Males and females appear similar. The fully developed larva is about 3/4 inch long, pinkish-beige, with visible legs and a brown head. (CM larvae do not have the 'anal comb' structure found on Oriental fruit moth larvae when examined under a microscope.) The pupa is approximately 3/8-inch long and brown, and eggs are approximately 1/25 inch in diameter, white, flat, and usually laid singly rather than in a mass.

Adult

Larva

Pupa

Eggs

Life History

CM overwinter as larvae in thick cocoons, changing to the brown pupal stage in early spring. They begin to emerge and mate in April or early May, depending on location. Eggs are laid on both leaves and fruit, and generally begin to hatch near the time of the first cover spray. Soon afterwards larvae tunnel into and feed inside the apples. After the feeding period, larvae leave the fruit and pupate on tree trunks and fallen branches. There are typically three generations per season in the Southeast.

Damage

The CM larvae usually tunnel directly into fruit, making a direct path to the core and sometimes feeding on the seeds. This is in contrast to Oriental fruit moth, which generally tunnels more randomly and does not usually infest the core. CM may also create 'stings' in fruit if the larvae is killed (i.e., by insecticides) before penetrating deeply into the fruit.

Interior damage

Exterior "sting" damage

Monitoring and Control

Base a decision to spray insecticides against CM on pheromone trap catches and the degree-day model below. Traps should be placed in orchards near the tight cluster stage of bud development, and checked one to two times per week. Traps should be hung at a density of one trap per 10 acres of orchard (traps hung in the upper third of the canopy often catch more moths than those in the lower canopy). The 'biofix' date is established when pheromone traps sustain a catch of two or more moths. (It is only necessary to check traps once per week after biofix is determined.) Begin to accumulate degree days at biofix. The degree-day table below uses daily maximum and minimum temperatures to determine daily degree-days for CM (base 50º F). The degree-day model predicts percent of adult emergence and egg hatch for each of the three to four generations of CM that annually occur in the Southeast.

CM in trap with pheromone lure

CM trap in orchard

First-Generation: Recommendations are provided for low and moderate to high population densities. Low-density orchards are those with less than 0.5 percent of the fruit damaged the previous year and pheromone trap catches that do not exceed 10 moths per trap per week anytime before the accumulation of 200 DD after biofix. In low-density orchards, make a single insecticide application at 350 DD after biofix. In moderate- to high-density orchards, apply two insecticide applications 14 days apart, the first at 150 to 250 DD after biofix: 150 if using a product which depends primarily on ovicidal activity for control (i.e., Confirm or Intrepid), and 250 if using an insecticide that has contact activity against larvae (i.e., organophosphate or pyrethroid).

Second-Generation: Recommendations are provided for extremely low, low, and moderate to high population densities. Extremely low-density orchards may not require an insecticide application (i.e., pheromone trap catches never exceed three moths per trap per week between 900 to 1,900 DD after biofix). Low-density orchards require one insecticide application at approximately 1,250 DD. These orchards may have no sign of damage by first generation larvae and trap catches between 3 to 7 moths per trap per week between 900 to 1,450 DD after biofix. Moderate- to high-density orchards will have fruit damage and higher pheromone trap catches requiring two insecticide applications 14 days apart starting about 1,250 DD after biofix.

Third-Generation: Apply an insecticide at 2,250 DD after biofix if pheromone trap catches exceed 5 moths per trap per week after 1,900 DD after biofix or if fruit damage caused by second-generation larvae is observed.

EXCEPTIONS TO THE MODEL: Where CM populations are extremely high and where pheromone trap catches remain high between generations, additional insecticide applications may be necessary. This often occurs in orchards adjacent to an abandoned orchard or where old bins are placed near an orchard. Insecticides recommended for CM have sufficient residual activity so that applications made at 14-day intervals usually provide adequate protection.

Insect and Mite Management Overview
Insect and Mite Index

Southeastern Apple Production
Mountain Horticultural Crops Research & Extension Center
455 Research Drive
Mills River, NC 28759
Phone: 828.684.3562 ~ Fax: 828.684.8715
Email: jim_walgenbach@ncsu.edu

Web Crafters: Anne S. Napier and Steve Schoof
Email: steve_schoof@ncsu.edu

Updated March 9, 2007