Botryosphaeria dothidea causing canker of grapevine newly reported in China

In the ummer of 2009 in Zhejiang, Jiangsu, Guangxi, Shanxi, Beijing, Tianjin and Hebei Province, we found a decline of grapevines (Vitis vinifera) with symptoms of dieback on one or more shoots, accompanied by elongated oval-shaped cankers in the wood, shrivelling and rot of fruit clusters (Fig. 1).We collected 121 diseased samples from affected areas and from these samples more than 1000 infected tissue pieces were used for pathogen isolation. Tissue from the lesion margins was surface-sterilized by placing in 75% ethanol for one min, then rinsing with sterilized water (three times) before placing on potato dextrose agar plates incubated at 28°C for five days (Niekerk et al., 2004). Hyphae from the colony margins were transferred to fresh agar plates to obtain pure isolates.

Botryosphaeria dothidea was isolated from 44 of the diseased samples. Colonies of . dothidea were white, becoming grey or dark brown with age. Pycnidia started to develop after 10 days. Conidia measured 17-32 x 4-9 µm. Some isolates were used for ITS sequence analysis to confirm the morphological identification. The primers ITS1 and ITS4 were used to amplify part of the nuclear rDNA operon by PCR (White et al., 1990). Ten ITS sequences were obtained (GenBank Accession Nos. GU226844 to GU226850, GU226852, GU226854 and GU226855). All sequences showed 99-100% homology with . dothidea(Urbez-Torres et al., 2006). This is the first report of grapevine canker associated with . dothidea in China .