Detection of procymidone resistance and investigation of biological characteristics in Botrytis cinerea

Resistant frequency of Botrytis cinerea isolates collected from different regions of Liaoning,Shanghai,Fujian and Inner Mongolia to procymidone was determined by discriminatory dose method.Baseline sensitivity of B.cinerea to procymidone was established using the sensitive isolates unexposed to procymidone.Resistant frequency to procymidone was compared between isolates from procymidone-exposed and unexposed regions.Resistance factor were calculated for resistant isolates from orchords with procymidone application for more than 10 years.Biological characteristics of resistant and sensitive isolates were studied.The results showed that the mean EC50 value of procymidone to 127 sensitive isolates was (0.31±0.08) μg/mL.Resistance to procymidone was observed in B. cinerea from all four provinces with very high resistant frequency,which was even higher (than 90%) in isolates from Liaoning and Inner Mongolia.The isolate from Liaoning province showed the highest resistant factor of 44.3 among 215 isolates from regions exposed to procymidone for more than 10 years.The resistance frequency in B. cinerea isolates from regions exposed to procymidone was higher than that from unexposed regions.The resistance was stable in resistant isolates.There was no correlation between resistant factor and biological characteristics including sporulation,spore germination,mycelial growth and pathogenicity in 4 sensitive and 7 resistant isolates.