Canker on bark of Populus spp. caused by Cytospora tritici, a new disease in China.
During a survey of landscape trees in 2007, Populus spp. with cankers were found in Fushun, Baoxing, and Luding counties and Chengdu city in Sichuan Province. In these trees, bark canker pathogens discolored the sapwood. During damp weather, conidia were pushed out and formed orange spore horns. The obtained isolates were cultured on PDA. ITS1-5.8S-ITS2 sequences were amplified via PCR from genomic DNA obtained from mycelia using universal primers ITS1 and ITS4. The amplification products showed 100% sequence homology with Cytospora tritici isolate DQ243812 from the GenBank database. The ITS sequences were submitted to GenBank (Accession Nos. JQ277333 to JQ277336). Pathogenicity was confirmed by inoculating 20 disinfected (70% ethanol) Populus tomentosa cuttings. In 18 of the 20 cuttings, the cambium developed a brown colour and appeared water soaked 15 days later, whereas controls did not develop any symptoms. C. tritici was reisolated from symptomatic tissues. This is thought to be the first report of C. tritici in China causing canker on Populus spp.