Objective  To identify the pathogen of camphor tree (Cinnamomum camphora) canker disease, the diseased branches of camphor tree were collected from the Fuling, Beibei and Yuzhong district of Chongqing.

Method  Pathogens were isolated from the diseased samples and purified by single-mycelium tips culture. The species of pathogens were primarily identified by the morphological characterizations of purified strains. To analyze the phylogenetic of the selected strains, the sequences of rDNA-ITS, β-tubulin and EF1-α genes were amplified and sequenced. The selected strains showing different morphological and molecular characteristics were tested for their pathogenicity on detached shoots of camphor.

Result  A total of 48 isolates were isolated from the diseased camphor tree canker samples in Chongqing, and 68 purified strains were obtained by single-mycelium tip technique. Based on the characterization of fungal colony and conidia, the 68 purified strains were grouped into three types. Fourteen strains from the three types were selected to construct phylogenetic tree. The phylogenetic analysis results showed that the three types belong to Botryosphaeria dothidea (type Ⅰ), B. parva (type Ⅱ) and B. rhodina (type Ⅲ). Pathogenicity tests on the camphor tree shoots showed that all the tested strains could induce canker lesions. Remarkably, the strains of B. parva exhibited the strongest virulence than that of the B. rhodina and B. dothidea strains. The B. dothidea strains showed the weakest virulence.

Conclusion B. parva, and B. rhodina are isolated from camphor canker disease for the first time. It is suggested that B. dothidea, B. parva, and B. rhodina are the common causal agents for camphor tree canker diseases in Chongqing.