重庆烟草棒孢霉叶斑病防治药剂筛选

Screening of Fungicides Against Corynespora Leaf Spot on Tobacco in Chongqing

为了筛选出防治重庆烟草棒孢霉叶斑病(Corynespora cassiicola)的有效药剂,本试验选取代森锰锌、百菌清、多菌灵、克菌丹、木霉复合菌剂和枯草芽孢杆菌共6种药剂,采用叶面喷施的施药方式对田间烟草棒孢霉叶斑病进行防治.田间试验结果表明,80%代森锰锌悬浮剂、50%多菌灵可湿性粉剂与75%百菌清可湿性粉剂对烟草棒孢霉叶斑病的防治效果最佳,相对防效分别为89.08%,87.74%和83.88%.同时,将代森锰锌和百菌清混配在叶面喷施可以有效降低烟草棒孢霉叶斑病的发病率,防效为80.68%,但无增效作用.由于多菌灵残效期较长,建议今后在烟草棒孢霉叶斑病的防控中轮换施用代森锰锌和百菌清,以减缓病菌抗药性的产生,保证防控效果.

In order to screen out effective fungicides for the prevention of Corynespora leaf spot on tobacco in Chongqing,a field experiment was made,in which mancozeb,chlorothalonil,carbendazim,trichoderma,trichoderma compounds or Bacillus subtilis was foliar sprayed on tobacco plants,with water spray as the control(CK).The results showed that 80%mancozeb suspension,50%carbendazim wettable powder and 75%chlorothalonil wettable powder gave the best control result,their relative control effect being 89.08%,87.74%and 87.74%,respectively.However,the residue period of carbendazim was too long to be recommended.Compounding of 80%mancozeb and 75%chlorothalonil also effectively reduced the incidence of Corynespora leaf spot of tobacco before the occurrence of the disease,with no synergism detected,though.Due to the long residual preiod of carbendazim,alternate application of mancozeb and chlorothalonil is recommended so as to delay the development of drug resistance in the pests and ensure the effects of disease control.