There are common and serious rose diseases that do much damage to roses such as Rose rust
(Phragmidium subcorticium), Powdery mildew (Sphaerotheca pannosa), Black spot, Rose phylloxytosis,
cercosporosis and Stem Canker. Black spot (Marssonina rosae) _ is the most serious diseases of roses. It
is caused by the fungus, Diplocarpon rosae. It is most severe during the late summer. Symptoms occur on
rose leaves as circular, brown spots appear on leaves which turn black over the period of time. In case of
severe infection, leaves turn yellow and often drop from the plant. Severely infected plants may have lost all
of their leaves and some measures should be taken to reduce and minimize future infections.