The Beast and the Beauty: What Do we know about Black Spot in Roses?

Abstract Black spot in roses caused by the hemibiotrophic ascomycete Diplocarpon rosae (Wolf) (anamorph Marssonina rosae) is the most devastating disease of field grown roses and, therefore, affects both consumers of ornamental roses and commercial production. Chemical control of the disease is restricted by regulations, and consumers increasingly demand resistant varieties. As breeding black spot resistant rose varieties is complicated by its polyploid nature and the regular emergence of new pathogenic races of the pathogen, a deeper understanding of the biological characteristics of the interaction between the fungal parasite and its host is urgently needed. This review summarizes some investigations of the parasite and its interactions from early descriptions of the pathogen to recent molecular analyses of the fungus.