This disease occurs mostly on older leaves, stems and pods also. Leaf blades initially have yellowish-white spots, slightly elevated, and then gradually expand to yellowish-brown blister spots (summer spore piles), which rupture the epidermis and disperse reddish (yellowish)-brown powdery material (summer spores). Summer spore piles mostly occur on the back of the leaves, and also on the leaf surface in severe cases. Later in the summer spore pile or on other parts of the diseased leaves to produce black winter spore pile. Sometimes small yellow spots (goniospores) are produced on the leaf surface and on the stems and pods, and later orange-red spots (rusts) are produced around these spots (on the stems and pods) or on the leaf surface, and then they continue to form summer and winter sporocarp piles further. Sex sporangia and rust sporangia rarely occur.