小麦白粉病菌对嘧菌酯和三唑酮的敏感性反应

为了解小麦白粉病菌对嘧菌酯和三唑酮的敏感性差异，采用与田间实际用药条件相似的离体叶段喷雾法比较了2014年河南、河北麦区的小麦白粉病菌对嘧菌酯和三唑酮的敏感性。结果表明，供试菌株对三唑酮的EC₅₀为53.93 mg·L^-1，抗性水平为15.14，抗性频率高达93.57%；对嘧菌酯的EC₅₀为0.235 mg·L^-1，抗性水平为0.539，未发现嘧菌酯抗性菌株。嘧菌酯对三唑酮敏感菌和抗药菌的毒力分别是三唑酮的59倍和1 396倍。嘧菌酯与三唑酮之间无交互抗性，可见嘧菌酯具有防治小麦白粉病的应用前景。

Sensitivity and Activity of Blumeria graminis f.sp.tritici to Azoxystrobin and Triadimefon

In order to clarify the difference in the sensitivity of Blumeria graminis f.sp.tritici isolates to azoxystrobin and triadimefon, the sensitivity of Blumeria graminis f.sp.tritici to triadimefon and azoxystrobin were tested with spraying leaf segments in vitro which was similar to the physical condition in field, and the isolates were collected from Henan and Hebei province.The results showed that the mean EC₅₀ value was 53.93 mg·L^-1 and the mean resistance factor was 15.14 to triadimefon,of which resistant frequency reached up to 93.57%. To azoxystrobin, the mean EC₅₀ value was 0.235 mg·L^-1 and the mean resistance factor was 0.539 to azoxystrobin.No resistant strain was found to azoxystrobin.The toxic of azoxystrobin is 1 396 and 59 times as much as triadimefon-resistance isolate and triadimefon-sensitivity isolate respectively.There was no cross-resistance between triadimefon and azoxystrobin. It will accelerate the reasonable use of azoxystrobin for wheat powdery mildew.