Abstract:

Abstract: Forty isolates of Apple Ring Rot（Botryosphaeria berengeriana f.sp.piricola） were collected from typical and representative location of Henan Province.The sensitivity of these isolates to tebuconazole was tested by colonial growth-rate.The result showed that the 50% effective concentration values (EC50) to the 47 strains for tebuconazole ranged from 0.0172 to 1.6026 μg/mL, and the mean EC50 values ( ±Se ×t0. 05) were 0.3978±0.1171 μg/mL. Isolate ZZ1 (EC50 1.6026 μg/mL )showed the lowest sensitivity to tebuconazole, strain LB1(0.0172 μg/mL) was the most sensitive strain to tebuconazole, its toxicity ratio was 620.38-fold compared to strain ZZ1. The results suggested that the population of Botryosphaeria berengeriana f.sp.piricola Henan province is sensitive to tebuconazole and populations with significant resistance have not been observed. A sensitivity baseline of Botryosphaeria berengeriana f.sp.piricola isolates in Henan province was set up.