| Fungus DT-014 of the Epicoccum, which was isolated from the leaves of Cephalanoplos setosum (Witld.) with naturally occurring disease in Yaozigou, Datong County, Xining City, Qinghai Province, was used as the research object. The pathogenicity of the strain DT-014 to 4 potted weeds Galium spurium L., Chenopodium album L., Malva verticillate L. var. Crispa, Elsholtzia densa Benth. and the safety of 5 potted crops Vicia faba L., Pisum sativum L., Hordeum vulgare L., Triticum aestivum L., Brassica napus L. were determined by fermentation spray inoculation. The single factor experiment method was used to explore the optimal growth medium, carbon source, nitrogen source and solid-state fermentation substrate of strain DT-014 by measuring the colony diameter and the OD600 value of spore suspension. The experimental results showed that DT-014 had strong pathogenicity to G. spurium and C. album, followed by E. densa and low pathogenicity to M. crispa. DT-014 was relatively safe for wheat T. aestivum, broad bean P. sativum, highland barley H. vulgare, and pea P. sativum, and slightly affected B. napus. The optimum medium for DT-014 was peptone medium, the optimum carbon source was glucose, the optimum nitrogen source was yeast extract, and the optimum solid\|state fermentation substrate was soybean powder. |