Garden Pests and Diseases: yellow spots on weeping crab apple, 3 by meredithwnyc

meredithwnyc wrote:
we moved into a new home with fabulous plantings, most of which i am unfamiliar with. i was told this is a weeping crabapple, but i have supplied photos of tree for confirmation. there has been an enormous amount of rain in the past month. in may, the leaves looked like the photo with the blossom. now almost all leaves are covered with these spots. some leaves have turned yellow and fallen off. can someone diagnose my problem and suggest how i might fight it, please. TIA