Characterisation of the fungi associated with esca diseased grapevines in South Africa
During the period from 2001 to 2008, grapevines showing foliar and/or internal symptoms of esca were collected from various grape-growing regions in South Africa. Isolations were made from typical internal wood symptoms associated with esca, and fungal isolates were characterized by cultural growth patterns, morphology and phylogenetic inference. The gene regions sequenced included the internal transcribed spacers and the 5.8S rRNA gene (ITS) for the basidiomycetes and Phomopsis isolates, the partial b-tubulin and actin genes for Phaeoacremonium isolates and the partial translation elongation 1-α gene and the ITS for the Botryosphaeriaceae isolates. The fungi identified included Phaeomoniella chlamydospora and six species of Phaeoacremonium including Pm. aleophilum, Pm. alvesii, Pm. parasiticum, Pm. iranianum, Pm. mortoniae and Pm. sicilianum, of which the latter three are reported for the first time in South Africa. The following taxa were also identified: Eutypa lata, Phomopsis viticola, Phomopsis theicola, Diaporthe ambigua, Diplodia seriata, Neofusicoccum australe and N. parvum. The basidiomycete isolates were distributed over ten well supported monophyletic clades among genera of the Hymenochaetales. Two of these clades could be identified as species of Fomitiporia and Phellinus.