Ilyonectria black foot rot associated with Proteaceae

Proteaceae is an important component of the South African cut flower industry. Propagation of these woody plants using vegetative cuttings is, however, hampered by fungal infections initiated in the nursery. Recently black foot rot disease symptoms were observed on vegetative cuttings of Protea and Leucospermum in a fynbos nursery near Stanford, Western Cape Province, South Africa. Isolations from symptomatic plant material revealed several isolates of Ilyonectria, which were identified as I. macrodidyma, I. torresensis and four novel taxa described here as I. capensis, I. leucospermi, I. protearum and I. vredehoekensis. Species were characterised based on DNA phylogenetic inference and morphological comparisons. Furthermore, pathogenicity tests were conducted, which confirmed all six Ilyonectria species capable of causing black foot rot of Proteaceae. Other than the novel plant pathogenic species described here, this study also represents the first report of black foot rot disease associated with the cultivation of Proteaceae cut flowers.