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
Probably apple scab which attacks crab apples. Clean up the fallen dead leaves in the fall. In the spring before flowering you can spray with an anti fungus such as Captan.
That is not apple scab but cedar apple rust. It is a fungus. Not much can be done at this point. But you can stop any further spread by applying a fungicide now and then repeating in 10-14 days.
Next year you will need to spray the trees with a fungicide at least 3 times in the spring...once at full flower, then at petal fall and then about 14 days later.
This fungus requires two hosts, apple or crabapple and eastern red cedar (Juniperus virginiana L.), to complete its life cycle. Spores produced on apple do not infect apple, but only cedar and spores produced on cedar infect only apple. One way to stop the disease is also to not have cedars within 2 miles of your crabs. Otherwise fungicides will be needed annually.
Clorothalonil, propiconazole and Mancozeb are some fungicides you can use.
http://plantclinic.cornell.edu/factsheets/CedarAppleRust.pdf
