Sensitivity of Japanese Fusarium graminearum species complex isolates to metconazole

Abstract

The sensitivity of the Fusarium graminearum species complex, the causal fungus of Fusarium head blight, to metconazole was measured. The minimum inhibitory concentrations (MIC) of 101 isolates ranged from 0.20 to 6.25 mg/l with a single peak at 1.56 mg/l. The effective concentration for 50% growth inhibition (EC 50 ) was Ͻ0.1 mg/l in about 80% of isolates, and no isolate was significantly less sensitive to metconazole among this group. Among the F. graminearum species complex, F. asiaticum and F. graminearum s. str. were identified by PCR-RFLP. The trichothecene chemotypes were determined as 3ADON, 15ADON, or NIV by multiplex PCR. Although species-specific geographical distributions and mycotoxin production characteristics were found, the MIC values to metconazole of both species were distributed within a similar range, and no significant difference in sensitivity was observed between the species or trichothecene chemotypes. Next, CYP51 genes from isolates with different sensitivities to metconazole were amplified by PCR, and their sequences were compared. As a result, it was suggested that the differences in sensitivity to metconazole between the isolates were not due to the substitution of amino acids in CYP51, the target enzyme of DMI. Then, macrospores from isolates with various sensitivities to metconazole were sprayed onto wheat ears, and the efficacy of metconazole was examined. Metconazole showed high control activity against every isolate.

Sensitivity of Fusarium graminearum causing head blight of wheat in Brazil to tebuconazole and metconazole fungicides

“…In China, Yin et al, (2009) assessed sensitivity of 40 F. graminearum isolates to tebuconazole and found a EC 50 mean of 0.248 mg/L (0.021-1.152 mg/L), which is much higher than those found in our study to both fungicides tested. However, in Japan, Tateishi et al (2010) studied 101 isolates representing F. graminearum and F. asiaticum populations and found that 80% of isolates showed EC 50 towards metconazole of less than 0.1mg/L, a level of sensitivity more similar to that found in the present study.…”

“…Fungicide sensitivity was quantified by measuring the radial growth of the cultures on PDA (potato dextrose agar) media (Becher et al, 2010;Tateishi et al, 2010) amended with increasing concentrations of tebuconazole (Tebuconazole Nortox 200 EC, Nortox S.A.) or metconazole (Caramba 90, BASF S.A.) (0.0; 0.01; 0.05; 0.1; 1 and 10 mg/L). The fungicides were added to PDA media in three replicates each.…”

In vitro sensitivity reduction of Fusarium graminearum to DMI and QoI fungicides

“…In general, fungicides containing triazole as the active ingredient (metconazole, prothioconazole and tebuconazole) are considered the most effective chemical compounds against Fg (8, 12,15,17,20,21,27).…”

Baseline sensitivity of Fusarium graminearum from wheat fields in Henan, China, to metconazole and analysis of cross resistance with carbendazim and phenamacril

“…In previous studies, similar results were detected in the Jiangsu F. graminearum population to metconazole with EC 50 values ranging from 0.0209 to 0.0838 μg/ml and an average of 0.0481 ± 0.0134 μg/ml (Duan et al, ). The mean EC 50 value of the Brazilian F. graminearum population from wheat fields was 0.037 μg/ml (Spolti et al, ), and the EC 50 value of 80% of 101 F. graminearum isolates recovered from wheat fields in Japan was lower than 0.1 μg/ml (Tateishi et al, ). These findings confirm that the DMI fungicide metconazole could effectively inhibit the mycelial growth of F. graminearum .…”