Pathogeny Identification and Biological Characteristics of the Leaf Spot Lesions of Osmamthus fragrans

In this study Phyllosticta spot pathogen was isolated from the leaf spot lesions of Osmamthus fragrans and identified as Phyllosticta ghaesembillae Koorders.Meantime the Pathogenicity and the biological characteristics were studied.The result showed: this pathogen can grow at pH value 3—11 and the most optimal pH value was 9.The most optimal temperature for the growth of hyphae and the generation of Pycnidium was 25?℃,but the most optimal temperature for germination of Conidia was 20?℃.No significant influence of illumination on the growth of hyphae was observed.Darkness helped the germination of spore.Many kinds of monosaccharide,disaccharides and polysaccharide can be used by the pathogen which did not influence the growth of hyphae but on the growth percentage of hyphae.The pathogen can utilize the organic nitrogen an inorganic nitrogen in which KNO3 was the suitable nitrogen source.(NH4)2SO4 and NH4Cl repressed the growth of pathogen.The lethal temperature of hyphae was 60?℃ per 10 min.