Apple Scab infection?
My apple trees have been infected with some kind of defoliating leaf fungus - based on what I've read about the symptoms. Can you confirm (see photos)? And if so, what can I do about it? These are old family trees - probably going on 40 years. No problems before this.
This does look like apple scab. https://extension.umd.edu/growit/diseases-apples-and-pears The best way to treat this fungal disease would be to follow a regular spray schedule, starting in the spring. We recommend following the Virginia Tech Home Fruit Preventative Spray Schedule, which can be found on the following web page. https://extension.umd.edu/growit/home-fruit-preventative-spray-schedule-and-management-common-proble...
This guide is updated every two years with the recommended products and schedule for preventing common diseases in apples.
There is also good information on the following page from Penn State University. https://extension.psu.edu/apple-scab-in-the-home-fruit-garden