The pathogen that causes rose black spot is the fungus Diplocarpon rosae. This fungus infects rose leaves, creating purple or black spots which often lead to early leaf drop and reduced plant vigor. Diplocarpon rosae is the most widespread and damaging fungus responsible for black spot disease on roses worldwide.
There are also other species occasionally reported as pathogens causing similar black spot symptoms on roses, such as Alternaria alternata and Gnomoniopsis rosae, but Diplocarpon rosae is the primary and classic causative agent of the rose black spot disease.
In summary, Diplocarpon rosae is the main fungal pathogen causing rose black spot disease.
