Botryosphaeriaceae associated with bunch rot of grapes in South Eastern Australia

Species of fungi belonging to the Botryosphaeriaceaeare responsible for the grapevine trunk disease Botryosphaeriacanker. While the epidemiology and distribution of Botryosphaeria canker in the wood of grapevines and other hosts has been widely researched, little is known about the epidemiology of these pathogens on grape berries.Frequent isolations of Botryosphaeriaceae have recently been reported from grape bunches, raising the question as to whether these fungi can be considered as primary bunch rot pathogens. A survey was conducted over two consecutive seasons (2007'2009) in two vineyards of the lower Hunter Valley with a known history of Botryosphaeria canker. Samples were taken from various parts of the grapevine at different phenological stages, as well as from the trunk of each grapevine.Fungi conforming to seven species of the Botryosphaeriaceae:Diplodia seriata, Neofusicoccum parvum, N. luteum,Dothiorella viticola, Lasiodiplodia theobromae,D. mutila and Botryosphaeria dothidea were isolated.The largest number of isolates originated from dormant buds and wood followed by berries at harvest. A small number of isolates was found on flowers and pea-sized berries. Isolates originating from different tissues werefound to be pathogenic on berries at harvest and one year-old canes of Shiraz and Chardonnay. In addition,dormant buds of glasshouse and field grown Chardonnay were inoculated with various Botryosphaeriaceae to investigate into the affect of Botryosphaeria infection on bud burst and shoot development.