Sensitivity of Fusarium graminearum from Hubei province to carbendazim, tebuconazole and prochloraz

In 2014, 206 single-spore isolates of Fusarium graminearum collected from seven districts in Hubei province were identified by morphology. Sensitivity of 100 randomly selected isolates to carbendazim, tebuconazole and prochloraz was assayed by using mycelium growth inhibition method, and the sensitivity baseline was established. The results showed that the EC50 values of carbendazim, tebuconazole and prochloraz to F. graminearum isolates were in the ranges of 0.115-0.705, 0.006-1.356 and 0.002-0.370 μg/mL, and mean values of 0.248, 0.181 and 0.040 μg/mL, respectively. The sensitivity distributions of the 100 isolates to these three fungicides all followed unimodal quasi-normal distribution, which indicated that the EC50 mean values could be used as the sensitivity baseline of F. graminearum in Hubei province to these three fungicides. Using 10 times of the mean EC50 value of each fungicide as the discriminatory dose, the sensitivity of F. graminearum in Hubei province was monitored from 2015-2016. The study showed that the average inhibition rates of carbendazim, tebuconazole and prochloraz to F. graminearum isolates were 100%, 85.14%, 82.35%, respectively, in 2015, and 100%, 76.67%, 73.62%, respectively, in 2016. In summary, F. graminearum isolates in Hubei province still wxhibit high sensitivity to carbendazim, tebuconazole and prochloraz, although the inhibition rates of tebuconazole and prochloraz were slightly decreased in 2016.