Hi Gordon, thanks for the question.

The damage appears to be plum curculio, however, apple maggot, and codling moth can also disfigure fruit. Application of the "Fruit Tree Spray" depends on timing, but it seems you have a handle on that. The frequency of the spraying is also important as is the correct strength of the spray.  It is important to follow the label instructions. Weather conditions or increased insect pressure may require reducing the time between sprayings as permitted by the label.  Some "Fruit Tree Spray" formulations may not be as effective as we would want.  It is also important to remove dropped fruit which could be the source for the next damaging generation.  Monitoring these pests can help you see what you are fighting and also help with timing.  Double check your spray label to make sure you have the rite dilution and the frequency.  Consider a different spray.  Check out the following links:

Identification, Management and Control of Major Apple Pests – Wisconsin Horticulture

Home Fruit Spray Schedule [fact sheet] | Extension (unh.edu)

I hope this is helpful.

Hi, would kaolin clay be effective in controlling plum curling disease on my apples? Thanks Gordon

Hi Gordon,

Kaolin clay can work against plum curculio, apple maggot, and codling moth but requires a building up the white coverage and maintaining it.  Picking up dropped fruit is still critical. Check out links for details.

https://www.canr.msu.edu/news/plum_curculio_management

Home Apple Orchard Pest Management Overview - Cooperative Extension: Insect Pests, Ticks and Plant Diseases - University of Maine Cooperative Extension (umaine.edu)