| The aim of this study was to explore the taxonomic and biological characteristics of the pathogen inducing Chinese angelica (Angelica sinensis) root rot and screen its effective fungicides. Conventional tissue isolation method was used to isolate and culture the pathogen and its pathogenicity was tested according to Koch′s postulate. The identification and biological characteristics of the pathogen were detected by combination of morphology and molecular biology methods. The indoor toxicity of pathogens was determined according to the mycelial growth rate. The results showed that the colony of pathogen of A. sinensis root rot was felt-shaped. On three media, the macroconidia were falcate with the size of (27.5-47.5）μm × (3.8-7.5）μm (n=50) with 1-5 sepiments; the microconidia were elliptic, reniform, fusiform on PDA and on SNA media; it has diversified form of insertion style, concatenation, spherical, irregular, with the size of 2.5-3.8 μm and reniform on CLA media, showing (3.8-15.0) μm × (2.5-7.5) μm (n=50) with 0 to 3 sepiments; the chlamydospores were formed in concatenation on CLA media; irregular on PDA media; spherical, irregular and formed on SNA media, showing (2.5-3.8) μm × (2.5-5.0) μm in size (n=50). The phylogenetic tree of the combined sequences was EF-1α, RPB1 and RPB2, demonstrated that the pathogen was Fusarium acuminatum. The optimum growth temperature of this pathogenic F.acuminatum was 25 ℃, the optimum initial pH was 9, and light has no significant effect on its growth. Indoor toxicity indicated that 10% difenoconazole WG achieved the greatest inhibitory effect on the F.acuminatum at a EC50 value of 83.71 mg/L. This study provided a theoretical basis for pathogen identification and chemical control of A. sinensis root rot in field. |
