First Report of Dothiorella iberica ('Botryosphaeria' iberica) associated with Grapevine Decline in Australia

Between November 2006 and April 2008, grapevines displaying foliar symptoms typical of Eutypa dieback or evidence of Botryosphaeria canker such as dead spurs, cankers, and bleached or discolored wood tissue, were surveyed from 93 vineyards throughout New South Wales and South Australia. The most prevalent fungi associated with grapevine decline in all regions were species currently or formerly connected with a teleomorph in Botryosphaeria Ces. & De Not. Seven species including Botryosphaeria dothidea, Neofusicoccum parvum, Diplodia seriata, D. mutila, Lasiodiplodia theobromae, Dothiorella viticola and D. iberica were isolated. To our knowledge, D. iberica has not been reported previously from grapevine in Australia. On potato dextrose agar (PDA) colonies were dark green to grey with sparse aerial mycelium, forming pycnidia after 14 days at 25°C. Conidia were heavily pigmented, brown to dark brown, consistently one-septate, oblong to ovoid with a rounded apex and rounded or truncate base. Conidia measured (17.8-) 21.3 to 21.6 (-25.2) × (7.7-) 9.6 to 9.8 (-11.8) µm, with a length/width ratio of 2.2 (n = 300). Identification was confirmed via sequence homology of rDNA internal transcribed spacer regions (ITS1-5.8S-ITS2) and partial sequences of the translation elongation factor 1-#2; gene (EF1-#2;). Representative isolates of D. iberica were deposited at the Australian Scientific Collections Unit (DAR78991-DAR78995). Sequences from the studied DNA regions of all isolates were deposited in GenBank (ITS, EU768874-EU768878; EF1-a, EU768880-EU768884). Confirmation of pathogenicity towards Vitis vinifera and determination of the role of this species in grapevine decline are currently under investigation.