嘧菌酯与吡唑醚菌酯对烟草白粉病菌的抑制作用及在烤烟漂浮育苗阶段的防治效果

采用小苗法测定了嘧菌酯和吡唑醚菌酯对烟草白粉病菌Erysiphe cichoracearum的毒力,以及对苗期烟草白粉病的预防和治疗作用及持效期。结果表明:嘧菌酯和吡唑醚菌酯对烟草白粉病菌抑制作用的EC50值分别为7.62和9.90 μg/mL,对该病害的预防和治疗作用的EC50值分别为8.76、12.34 μg/mL和17.32、23.40 μg/mL;2种药剂对烟草白粉病菌均具有较长的持效期,在有效成分56.25 g/hm2 剂量下、2次喷雾处理烟苗,30 d后的防效仍分别达到94.45%和88.53%;2种药剂对新生烟叶均具有良好的保护作用,且在实验剂量范围内对烟苗安全。

Toxicity and control efficacy of azoxystrobin and pyraclostrobin against Erysiphe cichoracearum on tobacco during seedling developing period

The toxicities,protective and curative activities,and persistence effects of azoxystrobin and pyraclostrobin against Erysiphe cichoracearum causing tobacco powdery mildew were studied through tobacco seedling assays.The results presented that azoxystrobin and pyraclostrobin both strongly inhibited the disease development,with EC50 values of 7.62 and 9.90 μg/mL,respectively;and they showed protective and curative effects against E.cichoracearum with EC50 values of 8.76,12.34 μg/mL, and 17.32,23.40 μg/mL,respectively.The two compounds had long persistence against E.cichoracearum on tobacco seedlings,with control efficacy of 94.45% and 88.53% respectively,when inoculation 30 days after treatment with 56.25 g(a.i.)/hm2 for two sprays.Azoxystrobin and pyraclostrobin both could protect the newly growing leaves against E.cichoracearum, and they were safe to tobacco seedlings at the concentration tested in this study.