Cane dieback of Dawn Seedless table grapevines (Vitis vinifera) in Western Australia caused by Botryosphaeria rhodina

Cane dieback of Dawn Seedless table grapevines in the Carnarvon horticultural district of Western Australia was identified as being caused by the fungal pathogen Botryosphaeria rhodina. Symptoms of cane dieback included progressive death of shoots, canes and trunks. Shoot and cane infections were usually associated with external lesions that were bleached in appearance. Lesions often contained minute black pycnidia ( 0.1 - 0.2mm in diameter) which were initially immersed and later became erumpent. Some shoot and cane lesions were less defined. Mature conidia were ovate ( 20 - 25 mu m by 15 - 20 mu m), dark brown and uni- septate with longitudinal striations. Immature conidia were of similar shape and size but were hyaline, and single- celled with no striations. This is the first report of B. rhodina causing significant decline of table grapes in Western Australia.