1Institute of Plant Protection，Liaoning Academy of Agricultural Sciences，Shenyang 110161，Liaoning，China；2Institute of Rice Research，Liaoning Academy of Agricultural Sciences，Shenyang 110101，Liaoning，China；3Nematology Institute of Northern China，Shenyang Agricultural University，Shenyang 110866，Liaoning，China
Abstract：In order to evaluate the sensitivity of Botrytis cinerea to fluazinam and existed cross-resistance between fluazinam and the other different fungicides，this study collected，separated and purified 206 single spore bacterial strain from tomato production areas of Liaoning Province，and determined their sensitivity baseline to fluazinam by mycelial growth rates method．Results showed that the EC50 values of tomato Botrytis cinerea to fluazinam in Liaoning Province was 0.001 3-0.073 1 μg · mL-1．The mean EC50 value was（0.022 7±0.014 5）μg·mL-1．The sensitivity frequency distribution presented a continuous unimodal curve in accordance with normal distribution．Therefore，EC50 average value（0.022 7±0.014 5）μg · mL-1 could be taken as sensitivity baseline of tomato Botrytis cinerea to fluazinam in Liaoning Province and be used in fields monitoring for resistance to drugs．Thirty-nine B. cinerea isolates，exhibiting different sensitivities to fluazinam selected from 206 bacterial strains were tested on their sensitivities to pyrimethanil，procymidone，fludioxonil，boscalid and iprodione．The results indicated that the inhibitory activities order of these 6 tested fungicides to tomato Botrytis cinerea were fluazinam＞fludioxonil＞boscalid＞iprodione＞procymidone＞pyrimethanil．There were no cross-resistance existing between fluazinam and pyrimethanil，iprodione，procymidone，boscalid，fludioxonil．
