Abstract: The study aimed to acquire high efficiency fungicides and novel mixed agent for the control of tomato gray mold. The inhibitory activities of 8 fungicides, fermentation supernatant of antagonistic bacteria and mixed agent of fermentation supernatant and chemical fungicides to Botrytis cinerea were tested with the mycelium growth rate method. The results showed that fludioxonil, prochloraz, tebuconazole and myclobutanil had high toxicity to Botrytis cinerea, and EC₅₀ were 0.031 92, 0.057 18, 0.185 60 and 0.805 30 μg·mL^-1, respectively. Followed by iprodione, pyrimethanil and chlorothalonil, their EC₅₀ were 4.204 90, 5.949 90 and 8.816 30 μg·mL^-1. The inhibitory effect of mancozeb was the worst with the EC₅₀ of 103.519 40 μg·mL^-1, and the EC₅₀ of fermentation supernatant of Bacillus amyloliquefaciens cultured for 72 h to Botrytis cinerea was 76.9 mL·L^-1. Horsfall's method was applied to screen the synergistic combinations. The toxicity ratio reached 1.61, 1.60, 1.53, 1.38 and 1.32 when the mixed proportion of fermentation supernatant and prochloraz, tebuconazole, mancozeb, fludioxonil and iprodione were 6:4, 4:6, 8:2, 9:1 and 7:3, respectively, which had obvious synergistic effect.

Key words: tomato gray mold, fungicide, toxicity, fermentation supernatant, mixture