The most sensitive isolate DY2 and the most not sensitive isolate F6 has been under tricyclazole pressure through 5 generations,the ECso has not showed going up.

• 并就最敏感菌株DY2与最不敏感菌株F6在药剂选择压下进行了筛选，经5代测定，并未发现EC_(50)值有显著升高的现象。