This border is usually surrounded by a more indeterminate reddish area. Minute elevations of the fungus fruiting bodies appear in the brown center, with longitudinal slits later appearing that expose black masses of spores. Common on most rose varieties. Purple to white spots on the canes and small dark gray, circular spots on the upper surface of the leaves. Smal cane lesions are slightly raised, circular, purple and quite superficial.
Lesions later become grayish-white.
The massing together of these tiny spots produces a whitish patch that later is surrounded by a purple margin. Lesions continue to enlarge until the cane is girdled and destroyed, leaving a brown dead area. First appears as pale yellow or reddish spots on bark of the cane. Spots enlarge and grow together, resulting in large infected areas on which small, black, fruiting bodies of the fungus may be found. More prevalent on hybrid tea roses.