What can I do to control codling moth on my apple trees? I’ve tried the nylon footies, but found that the damage was actually greater. It seems as if the rough texture of the stockings actually makes it easier for the pests to get a purchase on the surface of the fruit. Also, the stockings give the fruit a slightly off (petroleum-like) flavor. I don’t want to use toxic chemicals.
The web site for City Fruit has useful information about codling moth, including life cycle, traps, and preventive cultural practices (good garden hygiene includes not leaving fallen fruit on the ground, and thinning your apples when they are small–marble or walnut-sized–to one per fruit cluster).
There are several control options described by University of California’s Integrated Pest Management page on codling moth.
Excerpt:
“Organically acceptable tools for the control of codling moth include cultural control in conjunction with mating disruption and sprays of approved oils, codling moth granulovirus (Cyd-X), the Entrust formulations of spinosad, and kaolin clay (Surround).”
A local home gardener told me that she has had good luck using Surround kaolin clay. You do have to apply it several times (from late June on, every week or two), and it will make your trees look a bit ghostly, but it is worth a try. This Washington State University HortSense page focuses on apple maggot control, but lists kaolin clay as a preventive method.
A thorough description of Surround kaolin clay spray may be found on the site of the National Sustainable Agricultural Information Service.