Identification and Biology of Leaf Spot Pathogen on Chimonanthus salicifolius

  Objective  Pathogen that caused the leaf spot disease on Chimonanthus salicifolius was isolated and classified, and its biological characteristics determined.

  Method  Specimens of C. salicifolius plants infected by leaf spot disease at Shouning county in Fujian were collected for in vitro tissue culture in the laboratory. Morphological and molecular examinations were performed on the isolates. Biological properties and culture conditions including temperature, pH, light, carbon source, nitrogen source, and lethal temperature were scrutinized for the pathogenic identification and characterization.

  Result  Based on the morphology as well as the rDNA ITS and TUB sequences, the pathogen responsible for the disease was identified to be Ascomycetes Pleosporales Epicoccum sorghinum. It could grow at 5-30 ℃ with an optimum temperature at 25 ℃ and pH ranging from 5 to 9 in media of 11 various carbon sources including sucrose and 8 different nitrogen source including peptone under no specific light/dark conditions. The lethal temperature of the fungal mycelia was 52 ℃.

  Conclusion  E. sorghinum was identified to be the major pathogen that caused the leaf spot disease on C. salicifolius in Shouning county. It had strong ability to grow on, resist to, and survive under adverse conditions.