Yello color spots on my apple tree leaves
This is a rust disease. They are prevalent in our area, especially in wet years.
It is not curable, and prevention would have consisted of a regular spray schedule of fungicidal applications earlier in the year.
There is more about Apple Rust Diseases and other problems on this page:
Tree fruits are not easy to grow here without careful management and carefully timed and sometimes repeated chemical inputs. The link above has highlighted links to those management schedules.
Here too is our Apple page: http://extension.umd.edu/hgic/plants/apples
Thank you for the detailed response. I appreciate it.
You are welcome.