Codling Moth Monitoring

By Pam WolfeOn June 18 of this year our Santa Fe County extension agent, Tom Dominguez, set lures for Japanese beetles and for codling moths (Cydia pomonella) in several city parks, at the airport, and at one residence. The lures are checked weekly; to date no Japanese beetles have been observed, but codling moth infestations are evident at all locations.Introduced to North America by European settlers, the codling moth does not threaten the lives of the trees it infests—apple, pear, plum, quince, hawthorn, and walnut—but it does render the fruit unusable. Depending on climate, the codling moth will complete two to four generations per year. Insecticides can be effective, but timing is critical. Once larvae enter the fruit, pesticides are ineffective.Here’s a brief summary from the Colorado State University fact sheet [1]:

The caterpillar of the codling moth is the common “worm” in a wormy apple or pear.
Most injury is usually produced by the second generation, which begins in early summer.
Non-chemical controls that can reduce fruit damage include fruit thinning, prompt removal of infested fruit, bagging of fruit, and the use of certain traps.
Insecticides are useful when applied to coincide with periods when eggs are being laid and before the newly hatched caterpillars bore into fruit.
Pheromone traps can be useful in timing sprays.

What you can do now: 1) pick and destroy damaged fruit (look for frass—excrement of insect larvae—at entry and exit holes); 2) pick up and destroy dropped fruit; 3) band trunks [2].Effective timing of insecticide requires monitoring in early spring. The county extension office is planning a workshop for February 2019 to help homeowners better understand tree care and the pests that threaten trees in Santa Fe. If you are interested in this workshop, or if you want more information about codling moths, please leave contact information on the Master Gardener office phone (505-471-6251) or send an email to sfmgahotline@gmail.com.Notes: