Three newPhaeoacremoniumspecies on grapevines in New Zealand

Abstract

Three new species of Phaeoacremonium (Pm.) found in discoloured wood of grapevine are described and named Pm. armeniacum, Pm. globosum and Pm. occidentale. Phaeomoniella chlamydospora was isolated from the same vines, but no other Phaeoacremonium spp. were present. Phaeoacremonium spp. have been associated with Petri and esca diseases in grapevine. In pathogenicity trials, the new Phaeoacremonium spp. consistently caused brown discolouration in the inoculated wood. All species caused mortality of cv. 101–14 rootstock cuttings, 22–60% of cuttings surviving 10 weeks after inoculation. Rootstock cv. 5C was less susceptible, with 80–100% of cuttings surviving. The three new species of Phaeoacremonium are genetically distinct from all those previously described and also show subtle morphological differences in the structure and size of the phialides and conidia. Phylogenetic analysis of b-tubulin and actin genes showed that the new species Pm. globosum and Pm. armeniacum are closely related to Pm. argentinense from Argentina, while Pm. occidentale is more closely related to Pm. mortoniae from vineyards in the northern hemisphere. The new species were isolated from rootstock imported into New Zealand ∼25 years ago from California. They are not closely related to species known from grape in California, and no conclusion can be made about whether they were imported in the recent past on infected plants, or if they are indigenous to New Zealand. Many Phaeoacremonium species have a broad host range, and more intensive surveys of the native New Zealand flora and vineyards are needed before their origin can be determined. Additional keywords: Togninia, Vitis vinifera.