Abstract: 【Objective】To identify taxonomic status and biological characteristics of a rubber tree leaf spot disease pathogen,and to screen fungicides,so as to provide theoretical basis for the control and prevention.【Method】Rubber leaves infected with leaf spot collected from seedling nursery in Nuna Village,Qushui County,Puer City,Yunnan Province were taken as materials. Pathogens was isolated and purified by tissue isolation and single-spore isolation method,and their pathogenicity were determined by Koch's postulates test. Based on morphological characteristics and ITS,GADPH,TEF1-α multigene sequence analyses,the pathogen was classified and identified. Biological characteristics were determined with single factor variable experiment. Toxicities of 8 kinds of fungicides were tested through mycelial growth rate method.【Result】Two fungal isolates were obtained from the diseased rubber leaves through tissue isolating method,in which the spore morphology of JCMP17a was similar to that of the spores from diseased leaves. Isolate JCMP17a from the infected tissues was determined to be the pathogen of the disease through Koch's postulates. Morphological characteristics of the fungi were consistent with those of Bipolaris bicolor. According to multigene cluster analysis showed that the pathogen was clustered in the same evolutionary branch of phylogenetic tree with B. bicolor. For strain JCMP17a optimum mycelial growth temperature was 28 ℃ with p H of 7,and the lethal temperature for was 55 ℃ for 15 min. Diverse carbon resources could be used. The best carbon source was soluble starch,and the best nitrogen source was beef extract. Full darkness(0 L∶24 D),light and darkness alternation(12 L∶12 D)were good for mycelial growth. The best fungicides against the mycelial growth of the pathogen were 250 g/L of difenoconazole,30% of prochloraz and 250 g/L of tebuconazole with the EC₅₀ value of 0.1158,0.2427 and 0.2613 mg/L.【Conclusion】Leaf spot disease pathogen from the germplasm nursery in seedling nursery in Nuna Village,Qushui County,Puer City,Yunnan province is caused by B. bicolor.This is the first report of B. bicolor infection on rubber tree in Yunnan rubber planting area. 250 g/L difenoconazole emulsifiable concentrate,30% prochloraz aqueous capsule suspension and 250 g/L tebuconazole emulsion in water can be used as alternative chemicals for control of leaf spot disease in rubber tree caused by B. bicolor.