Baseline sensitivity of Fulvia fulva on tomato to flusilazole and resistance risk analysis

Infacted tomato leaves were collected from protected fields without exposure to flusioazole in different regions of Liaoning Province to obtain 43 Fulvia fulva wild-type single-spore isolates. The baseline sensitivity was determined by measuring mycelial growth rate. The results showed that the baseline sensitivity of 43 isolates ranged from 0.1519 #mu#g/mL to 4.6475 #mu#g/mL. The mean EC_(50) value was 1.2351 #mu#g/mL. Two UV mutants with 6.0 and 7.6 resistance times to flusilazole from a wild-type isolate were obtained. The mutants also showed reduced growth and sporulation. The results indicated that the resistance risk of Fulvia fulva to flusilazole was low.