Fungicides ae usually needed for adequate control. Maneb, mancozeb, chlorothalonil, metiram, strobilurins, and copper fungicides are the most widely used products. Where the disease is severe and environmental conditions are favorable for he pathogen, several applications are usually required to produce acceptable control. In humid climates, applications begin when the spring flush is one-fourth expanded Where humid conditions exist, follow-up sprays could be required. Good Luck with your tree. We would appreciate hearing out how your tree is doing. (Taken from the Compendium of Citrus Diseases.)