啶酰菌胺等8种杀菌剂对烟草叶斑病菌的生物活性

Bioactivities of boscalid,etc.eight fungicides against the pathogen of tobacco leaf spot

采用生物测定方法分析了烟草叶斑病菌Didymella segeticola在菌丝生长阶段对8种杀菌剂(啶酰菌胺、苯醚甲环唑、丙环唑、氟硅唑、多菌灵、咪鲜胺、菌核净和代森锰锌)的敏感性,同时通过离体叶片法测定了8种杀菌剂对烟草叶斑病的保护和治疗作用。结果表明:供试8种杀菌剂对D.segeticola菌丝生长表现出不同的抑制活性,同时对其引起的病害具有一定的保护和治疗作用。抑菌活性最强的是啶酰菌胺,其平均EC_(50)值为(0.0470±0.0120)mg/L;其次依次为苯醚甲环唑[(0.0790±0.0050)mg/L]、咪鲜胺[(0.29±0.08)mg/L]、丙环唑[(0.69±0.12)mg/L]、菌核净[(1.08±0.33)mg/L]、多菌灵[(1.22±0.29)mg/L]、氟硅唑[(1.38±0.07)mg/L];代森锰锌的抑菌活性最弱[(22.80±10.51)mg/L]。进一步研究表明,氟硅唑、苯醚甲环唑、丙环唑、啶酰菌胺、菌核净和多菌灵对烟草叶斑病保护作用较强,25 mg/L药剂质量浓度处理下防效均>82%;100 mg/L代森锰锌处理下防效为70.51%。啶酰菌胺和氟硅唑对叶斑病具有较好的治疗活性,25 mg/L下防效均>80%;其次为咪鲜胺、苯醚甲环唑、多菌灵和菌核净;代森锰锌的治疗作用较差,100 mg/L下的防效仅为63.31%。研究结果可为烟草叶斑病防治药剂筛选提供参考和依据。

Bioactivities of eight fungicides(boscalid,difenoconazole,propiconazole,flusilazole,carbendazim,prochloraz,dimethachlon,mancozeb)to the pathogen of a tobacco leaf spot,Didymella segeticola,were determined using bioassay method at the mycelial growth stage.In vivo protective and curative effects of these fungicides against D.segeticolla on detached tabbaco leaves were also analyzed.The results showed that eight fungicides exhibited different inhibitory activities against mycelial growth of the pathogen,and also showed some protective and curative efficacies against the leaf spot.The most effecient one against mycelial growth of the pathogen was boscalid,with an EC_(50) value of(0.0470±0.0120)mg/L;followed by difenoconazole[(0.0790±0.0050)mg/L],prochloraz[(0.29±0.08)mg/L],propiconazole[(0.69±0.12)mg/L],dimethachlon[(1.08±0.33)mg/L],carbendazim[(1.22±0.29)mg/L],flusilazole[(1.38±0.07)mg/L];and most least effecient one was mancozeb with an EC_(50) value of(22.80±10.51)mg/L.Flusilazole,difenoconazole,propiconazole,boscalid and dimethachlon all had better protective activity for the control of this disease with>82%efficacy at 25 mg/L dosage treatment than 100 mg/L mancozeb showed 70.51%efficacy.Both boscalid and flusilazole showed better curative activities,with efficacies of>80%at 25 mg/L dosage treatment,followed by prochloraz,difenoconazole,carbendazim and dimethachlon;mancozeb showed relatively poor activity with 63.31%efficacy at 100 mg/L dosage treatment.The results provide scientific basis and reference for the screening of fungicides to control tobacco leaf spot.