Pathogenicity of Botryosphaeriaceous fungi isolated from grapevines in southeastern Australia

Botryosphaeriaceae species are among the most common fungi isolated from grapevine (Vitis vinifera) cankers. Eight species isolated from grapevines in southeastern Australia were used in a pathogenicity study on mature wood of 15-year-old Chardonnay. All eight species were pathogenic to grapevines under field conditions causing vascular discoloration and/or staining of the wood (lesions). Differences were evident among species (P<0.001). Neofusicoccum parvum and Lasiodiplodia theobromae were the most pathogenic based on lesion length, followed by Neofusicoccum australe, Botryosphaeria dothidea and Diplodia mutila and thereafter by Dothiorella viticola, Dothiorella iberica and Diplodia seriata. Optimum growth temperatures were also established for each species. Lasiodiplodia theobromae and B. dothidea grew optimally between 29 and 30C, Diplodia and Neofusiccocum spp. between 25 and 27C, and Dothiorella spp. at temperatures between 22 and 24C. The pathogenicity of Botryosphaeriaceous fungi on grapevines is discussed in context with data on the prevalence and distribution of these species in vineyards of southeastern Australia.