Cercospora leaf spot is a disease often confused with black spot due to the similarities in disease symptoms. Symptoms are circular spots usually 2-10 mm in diameter. The initial symptoms usually have a small purplish area.
Lesions on the underside of the leaves
As the disease progresses, the older lesions have small necrotic areas. Subsequently, the centers of the spots turn tan. The disease causes severe defoliation in heavily infected plants