A diverse range of Phytophthora species from botanical gardens in South Africa, including the novel Clade 5 species, Phytophthora mammiformis sp. nov

The genus contains many destructive and globally important plant pathogens. In the last decade, targeted sampling efforts have resulted in a dramatic increase in the number of known species, as well as a better understanding of their global distribution. Routine activities undertaken in botanical gardens, combined with great numbers of local and international visitors, place botanical gardens at risk to the accidental introduction and establishment of pathogens such as spp. In this study, the occurrence of was investigated in two botanical gardens in the KwaZulu-Natal Province of South Africa. Symptomatic collar and stem tissues were collected, and root and rhizosphere soil samples were taken from trees exhibiting symptoms of decline. Standard baiting techniques and direct plating of symptomatic tissues revealed the presence of seven species of residing in four phylogenetic clades. Five of these species, and the informally designated taxon sp. stellaris were known to be present in South Africa and was recorded for the first time. Of these, represented a novel host-pathogen association causing bleeding cankers on indigenous . A multilocus phylogenetic analysis based on ITS, and sequences showed the presence of an undescribed species belonging to the ITS Clade 5. This species is described here as . This study highlights the importance of monitoring botanical gardens for the detection and discovery of pathogens and emphasises their value as sites for the discovery of novel host-pathogen associations. Paap T, Balocchi F, Burgess TI, Bose T, Wingfield MJ (2024). A diverse range of species from botanical gardens in South Africa, including the novel Clade 5 species, . : 111-122. doi: 10.3114/fuse.2024.13.05.