苹果叶枯病和斑点落叶病菌生防芽胞杆菌筛选及活性评价OA

This study aimed to screen biocontrol strains of Bacillus with strong antagonistic activity against the apple leaf blight pathogen(Alternaria tenuissima)and apple leaf spot pathogen(A.alter-nata),and to evaluate their disease control efficacy.The inhibition rates of five biocontrol Bacillus strainsagainst A.tenuissima and A.alternata were assessed using paper disc diffusion method and fer-mentation filtrate-amended medium method.The control efficacy against the two diseases was evalua-ted using an in vitro leaf inoculation method.The results showed that B.subtilis B2 exhibited the highest antagonistic activity against both pathogens after treatment with the fermentation broth of five biocontrol Bacillus strains.The inhibition rates of B.subtilis B2 for A.tenuissima and A.alternata on the 7th day were 78.84％and 79.82％,respectively.With increasing dilution levels of the fermenta-tion filtrates of the five Bacillus strains,the inhibitory effect on A.tenuissima and A.alternata gradu-ally decreased.Among the five Bacillus strains tested,the inhibition rates of B.subtilis B2 fermenta-tion filtrate on A.tenuissima and A.alternata were 98.38％and 96.30％at a 5-fold dilution,respec-tively.In addition,control efficacy of B.subtilis B2 fermentation filtrate on apple leaf blight and leaf spot diseases was 68.10％and 65.70％,respectively.Therefore,B.subtilis B2 exhibited the highest inhibitory effect on the growth of A.tenuissima and A.alternata,and demonstrated strong biocontrol efficacy.