Susceptibility of Botryosphaeria dothidea to tebuconazole and virulence of its resistant mutants
130 Botryosphaeria dothidea isolates were collected from major apple-produced regions to assess the sus-ceptibility to tebuconazole by mycelium growth rate method and to test the virulence of resistance mutants.Resist-ant mutants were obtained by chemical screening and UV irradiation in the laboratory,and the fitness parameters of resistant and susceptible isolates were measured.The results showed that the EC50 values of 130 isolates varied from 0.051 6-1.925 4 μg/mL with the mean of (0.799 6±0.039 1)μg/mL and low resistant subcolony has been discovered.The resistant ratio of tested isolates was 71.54% and high-resistant strains has not discovered in major apple-produced regions.The resistance level of three resistant mutants was high with the resistant ratio of 58.82, 41.60 and 38.19 times,respectively.The fitness and virulence of resistant mutants had no significant difference between resistant and susceptible isolates.The resistance ratio of mutants decreased gradually after 9 generations of subcultures in the absence of fungicides and the resistance could not inherit stably.The results indicated that the resistance of B .dothidea to tebuconazole could gradually decline when the field selection pressure became lower.
NETL
NSTL
万方数据
维普
