Larvae cause two types of fruit damage: deep entry, where larvae burrow down into the core of fruit, pushing frass out as they go; and shallow entry where feeding occurs, but no tunneling is present. Both forms of damage render fruit unmarketable. Second generation larvae cause the most damage.
- Codling moth overwinters as a full-grown larva. Pupation occurs during bloom. First adults emerge at 150 DD, base 50 ℉., when counting from January 1. Warmer spring temperatures can accelerate the growth of codling moth, leading to earlier developmental milestones (like egg-laying and hatching).
- Newly hatched larvae are pale yellow with a black head, twice the width of its body. Mature larvae are pinkish-white with a brown head.
- Adult codling moth is gray-brown with alternating lighter gray and white bands across wings. Wings are marked at the back end by a coppery area that helps distinguish codling moth from other similar moths.
- Females can lay up to 100 eggs. Early season eggs are generally laid on leaves whereas later generations are usually laid on fruit. There are usually 2 generations in New England.
- Pheromone traps should be hung by bloom, on the north side of the tree at eye level. Hang traps in orchard areas where moths are most likely to enter from alternate host sites. Check traps twice a week and begin accumulating degree-days (base 50) after sustained catches in pheromone traps (biofix).
- First insecticide applications should be made ~ 250 DD (base 50) after biofix. First insecticide applications for the second generation should be made at about 1,400 DD to 1,600 DD, using the same biofix as previous spray timing.
- Remove abandoned apple and pear trees, where practicable. Trunk banding can be a useful method of reducing codling moth pressure. Cardboard wrapped around trunks before larvae move to cocooning sites will cause them to pupate on the cardboard, which is subsequently removed and destroyed prior to adult emergence. Hot water treatment of storage bins can destroy a number of overwintering larvae.
- Mating disruption, set up before bloom, can be an effective way to reduce codling moth populations. Mating disruption is also needed in July for the second generation. Plan on supplementing mating disruption with insecticides. Using mating disruption in conjunction with insecticides is especially important for orchards with recent history of CM fruit injury or in the first year of a disruption program.
- Many insecticides are effective against codling moth when applied against newly hatching larvae. Resistance to pyrethroids and organophosphates, however, has been found in many areas of the Northeast.