The Anthracnose disease attacks the leaves causing premature leaf drop. The fungi overwinters in the twigs and then infects the leaves in the spring.
This disease should be treated in the fall with a fungicide and then fertilized in the spring to help the tree recover with greater food production
Crabapple Rust and Scab is a spring disease. 4 applications of a fungicide to protect the new leaves. Without a protectant treatment, the leaves get infected and fall off during the months of July and August. Without leaves , the plant can not product food for next year.
Tip Blight is a spring disease that attacks and kills the newly emerging growth ( candles ) of Austrian and Ponderosa pines