Ypema H L, Ypema M, Gubler W D
Department of Plant Pathology, University of California, Davis 95616.
Plant Dis. 1997 Mar;81(3):293-297. doi: 10.1094/PDIS.1997.81.3.293.
Sensitivity of Uncinula necator subcultures to benomyl and the demethylation-inhibiting (DMI) fungicides triadimefon, myclobutanil, and fenarimol was assessed in 1993, 1994, and 1995 with leaf disk bioassays. In 1993, 1994, and 1995, 81.8, 96, and 96.7% of the subcultures, respectively, did not grow on leaf disks treated with 30 mg of benomyl per liter, whereas growth of the remaining subcultures was inhibited by more than 90%. Median EC values of triadimefon, myclobutanil, and fenarimol decreased from 1993 to 1994, and those of triadimefon decreased again from 1994 to 1995. In the same period, median EC values of all three DMI fungicides increased in a vineyard never exposed to DMI fungicides. The highest means and ranges of EC values found were those of triadimefon. Means and ranges were lower for myclobutanil and lowest for fenarimol, reflecting differences in inherent activities of the fungicides and po-tential for development of resistance. Pairwise correlations between EC values of each DMI fungicide were positive and confirmed earlier indications of cross resistance.
1993年、1994年和1995年，采用叶盘生物测定法评估了葡萄白粉菌（Uncinula necator）亚培养物对苯菌灵以及脱甲基抑制（DMI）类杀菌剂三唑酮、腈菌唑和粉锈宁的敏感性。1993年、1994年和1995年，分别有81.8%、96%和96.7%的亚培养物在每升含30毫克苯菌灵的叶盘上不生长，而其余亚培养物的生长受到90%以上的抑制。三唑酮、腈菌唑和粉锈宁的半数有效浓度（EC）值从1993年到1994年下降，三唑酮的半数有效浓度值从1994年到1995年再次下降。同一时期，在从未接触过DMI类杀菌剂的葡萄园里，所有三种DMI类杀菌剂的半数有效浓度值都有所上升。所发现的EC值的最高平均值和范围是三唑酮的。腈菌唑的平均值和范围较低，粉锈宁的最低，这反映了杀菌剂内在活性的差异以及产生抗性的可能性。每种DMI类杀菌剂的EC值之间的成对相关性为正，证实了早期关于交叉抗性的迹象。
