不同杀菌剂对烟草赤星病菌室内毒力测定

Determination of Laboratory Toxicities of Different Fungicides on Tobacco Brown Spot

【目的】筛选防治烟草赤星病的有效药剂。【方法】采用菌丝生长速率法和孢子萌发法测定7种杀菌剂对烟草赤星病菌(Alternaria alternata)的毒力作用。【结果】菌丝生长速率法中56%啶酰·肟菌酯、50%啶酰菌胺、30%肟菌·戊唑醇、72%霜脲·锰锌、80%戊唑醇、30%丙硫菌唑、50%氯溴异氰尿酸的EC_(50)值分别为0.1525,0.1603,0.2420,1.8137,4.5663,14.8457,86.9761 mg/L,孢子萌发法中50%啶酰菌胺、50%氯溴异氰尿酸、56%啶酰·肟菌酯、72%霜脲·锰锌、80%戊唑醇、30%肟菌·戊唑醇、30%丙硫菌唑的EC_(50)值分别为0.1272,0.1333,0.2088,1.3191,1.8218,3.1282,27.0458 mg/L。供试的7种杀菌剂中对菌丝生长的抑制效果最好的是56%啶酰·肟菌酯,EC_(50)值为0.1525 mg/L;对孢子萌发的抑制效果最好的是50%啶酰菌胺,EC_(50)值为0.1272 mg/L。【结论】56%啶酰·肟菌酯和50%啶酰菌胺可优先作为烟草赤星病田间防治实验用药,72%霜脲·锰锌和30%肟菌·戊唑醇可用作交替使用杀菌剂。

[Objective]This study was conducted to screen effective fungicides for the prevention and control of tobacco brown spot.[Method]The virulence of seven fungicides against Alternaria alternata were determined by mycelial growth rate method and spore germination method.[Result]The EC_(50) values of 56%boscalid-oxime,50%boscalid,30%oxime tebuconazole,72%fenoxycarb-manganese zinc,80%tebuconazole,30%prothioconazole and 50%chlorobromoisocyanuric acid in the mycelial growth rate method were 0.1525,0.1603,0.2420,1.8137,4.5663,14.8457,86.9761 mg/L.While,the EC_(50) values of 50%boscalid,50%chlorobromoisocyanuric acid,56%boscalid-oxime,72%thiram-manganese zinc,80%tebuconazole,30%oxime tebuconazole,and 30%prothioconazole in the spore germination method were 0.1272,0.1333,0.2088,1.3191,1.8218,3.1282,27.0458 mg/L.The control effect of 56%boscalid-oxime on Alternaria alternata in tobacco was the best inhibitor of mycelial growth among the seven fungicides,with EC_(50) of 0.1525 mg/L;and,the best inhibitor of spore germination was 50%boscalid,with EC_(50) of 0.1272 mg/L.[Conclusion]56%boscalid-oxime and 50%boscalid could be preferred for experimental field prevention and control of tobacco brown spot,and 72%fenoxycarb-manganese zinc and 30%oxime tebuconazole could be used as alternate fungicides.