Survey of Botryosphaeriaceae associated with grapevine decline in the Hunter Valley and Mudgee grape growing regions of New South Wales

Species belonging to the fungal family Botryosphaeriaceae are important pathogens of grapevines in Australia. A survey of declining grapevines in the Hunter Valley and Mudgee grape growing regions of New South Wales revealed 36% were infected with species belonging to the Botryosphaeriaceae. The incidence of Diplodia seriata was greatest, followed by Neofusicoccum parvum, Botryosphaeria dothidea and Lasiodiplodia theobromae. These identifications were made using a combination of molecular and morphological characters. Although D. seriata was the most common species found, its role as a primary pathogen of grapevines in Australia is yet to be ascertained. The accuracy of estimating the incidence of species was increased by surveying up to 25 grapevines per vineyard and by sampling both the trunks and cordons. Other pathogens capable of causing trunk diseases were also isolated in this survey, demonstrating that diagnosis based on symptoms alone is not sufficient and isolations on artificial media and sometimes DNA sequencing are required for a definitive diagnosis of the causal organism of decline.