Abstract：To identify the potential pathogen and test its biological characteristics of Pandanus pygmaeus, the pathogen strain t1 was isolated and purified from the infected leaves of P. pygmaeus by tissue isolation method. The species specification and biological characterization were determined by pathogenicity assay, morphological observation and molecular biology assay of the strain.The results showed that the pathogen causing P. pygmaeus leaf spot was Colletotrichum siamense. The optimal conditions for the growth of pathogenic strain t1 were 28 ℃, pH 7, and various carbon and nitrogen sources were available; the optimal conditions for sporulation of C. siamense production were 28 ℃, pH 10, continuous light, and the carbon and nitrogen sources were cellulose and peptone, respectively. Mycelial growth was favored under dark conditions for 24 h, while the maximum sporulation was achieved under continuous light for 24 h. The pathogenic mycelium was killed at 55 ℃ and 10 min. This is the first study on P. pygmaeus leaf spot disease caused by C. siamense in China, which will help to understand the biological characteristics of the disease and provide reference for its control.
2023, Vol. 36 
