Baseline sensitivity of Botrytis cinerea to fluazinam and cross-resistance to different fungicides in Fujian province

To evaluate the sensitivity of Botrytis cinerea to fluazinam and the existed cross-resistance between fluazinam and other fungicides, 106 single spore isolates of B. cinerea were collected from tomato in Fujian province. The sensitivities of B. cinerea isolates to fluazinam were determined by mycelial growth rate test. The results showed that EC50 values of 106 isolates to fluazinam followed a unimodal curve, ranging from 0.003 7 to 0.045 2 μg/mL with the mean EC50 value of (0.022 1 ±0.009 8) μg/mL. Thus, the data could be employed as the baseline-sensitivity of B. cinerea to fluazinam which could be used for the field resistance monitoring. And the sensitivities of 15 isolates of B.cinerea, which exhibited different sensitivities to fluazinam, to pyrimethanil, iprodione, procymidone and picoxystrobin, were also tested with the mycelial growth rate method. The mycelial growth inhibition rates of the above mentioned 5 fungicides were fluazinam> iprodione> procymidone> picoxystrobin> pyrimethanil. No cross-resistance between fluazinam and other 4 fungicides was observed.