cherry leaf spot blumeriella jaapii small circular fungal disease lesions on the leaf of a sweet cherry leaf

agriculture biology blight blumeriella botany cherry circular closeup control damage disease diseased environment farm farming flower fungal fungi fungicide fungus garden gardening green grow growing infection jaapii leaf leaves lesions macro mold natural nature outdoor own parasite pathogen pathology pest phytopathology phytophthora plant problem science small spores spot spring summer sweet symptoms tree unhealthy your