枯草芽孢杆菌NCD-2与化学杀菌剂复配对棉花黄萎病的防治效果

Control effects of combination of Bacillus subtilis NCD-2 and chemical fungicides on cotton Verticillium wilt

【目的】研究枯草芽孢杆菌(Bacillus subtilis)NCD-2与化学杀菌剂复配对棉花黄萎病的防治效果,为防治棉花黄萎病提供理论依据。【方法】以棉花黄萎病致病菌大丽轮枝菌(Verticillium dahliae)强致病力菌株Vd080为研究对象,采用生长速率法测定戊唑醇、氟啶胺、咪鲜胺、代森锰锌和百菌清这5种杀菌剂的毒力;用对峙培养法测定NCD-2对Vd080的毒力;筛选出与NCD-2相容性好的杀菌剂,进一步采用Horsfall法确定菌药复配比例;在室内开展盆栽试验,评价不同复配处理对棉花黄萎病的防治效果(防效)。【结果】5种杀菌剂中咪鲜胺对Vd080的抑制效果最好,其有效中浓度为0.027 mg·L^(-1),戊唑醇和氟啶胺的抑制效果次之。NCD-2对Vd080的有效抑制中浓度为2.56×10^(7)mL^(-1)(菌体浓度,后同)。0.4 mg·L^(-1)氟啶胺与2.56×10^(7)mL^(-1)NCD-2的相容性最好,达到79.19%;2.0 mg·L^(-1)氟啶胺、0.02 mg·L^(-1)咪鲜胺次之,二者与2.56×10^(7)mL^(-1)NCD-2的相容性分别为71.29%和63.20%。2.56×10^(7)mL^(-1)NCD-2与0.4 mg·L^(-1)氟啶胺、2.0 mg·L^(-1)氟啶胺和0.02 mg·L^(-1)咪鲜胺分别按照体积比3∶7、9∶1和1∶1进行复配时,增效作用最强,对Vd080的抑菌效果最好。室内盆栽试验发现,2.56×10^(7)mL^(-1)枯草芽孢杆菌NCD-2与0.02 mg·L^(-1)咪鲜胺按体积比1∶1复配时,棉花黄萎病病情指数最低,防效最好(82.81%),具有很好的增效作用(增效系数为23.46)。【结论】2.56×10^(7)mL^(-1)枯草芽孢杆菌NCD-2与0.02 mg·L^(-1)咪鲜胺按体积比1∶1复配对棉花黄萎病有很好的防治效果,且具有明显的增效作用。

[Objective]This research aims to study the effects of the combination of Bacillus subtilis NCD-2 and chemical fungicides on the control of cotton Verticillium wilt,so as to provide a theoretical basis for the control of cotton Verticillium wilt.[Methods]The virulent Verticillium dahliae strain Vd080,a pathogen causing cotton Verticillium wilt was used as the object,and the virulence of 5 fungicides(tebuconazole,fluazinam,prochloraz,mancozeb and chlorothalonil)were determined by growth rate method.The toxicity of NCD-2 to Vd080 was determined by dual-culture method.The fungicides with better compatibility with NCD-2 were selected,and the volume ratio of fungicides and NCD-2 was further determined by Horsfall method.The control effects on cotton Verticillium wilt of different compound treatments were evaluated in the indoor pot experiment.[Results]Among the 5 fungicides,prochloraz had the best inhibitory effect on Vd080,and its median effective concentration(EC50)was 0.027 mg·L^(-1),followed by tebuconazole and fluazinam.The EC50 of NCD-2 to Vd080 is 2.56×10^(7)mL^(-1)(cell concentration).The compatibility of 0.4 mg·L^(-1)fluazinam with 2.56×10^(7)mL^(-1)NCD-2 was best,reaching 79.19%.The compatibility of 2.0 mg·L^(-1)fluazinam and 0.02 mg·L^(-1)prochloraz with 2.56×10^(7)mL^(-1)NCD-2 were 71.29%and 63.20%respectively.The synergistic effect of 2.56×10^(7)mL^(-1)NCD-2 was the strongest when mixed with 0.4 mg·L^(-1)fluazinam,2.0 mg·L^(-1)fluazinam,and 0.02 mg·L^(-1)prochloraz at the volume ratios of 3∶7,9∶1 and 1∶1,respectively,and the inhibitory effect on Vd080 was the best.The indoor pot experiment showed that when 2.56×10^(7)mL^(-1)Bacillus subtilis NCD-2 and 0.02 mg·L^(-1)prochloraz were mixed at the volume ratio of 1∶1,the disease index of cotton Verticillium wilt was the lowest,the control effect was the best(82.81%),and the synergistic effect was good(synergistic coefficient was 23.46).[Conclusion]The combination of 2.56×10^(7)mL^(-1)Bacillus subtilis NCD-2 and 0.02 mg·L^(-1)prochloraz at the volume ratio of 1∶1 has a good control effect on cotton Verticillium wilt,and good synergistic effect.