叶菌唑及其复配剂对河南省假禾谷镰孢菌的抑制活性 及对小麦茎基腐病的室内防效.

Fusarium crown rot (FCR), mainly caused by Fusarium pseudograminearum, is a serious fungal disease that affects wheat yield. To determine the inhibitory activity of metconazole to F. pseudograminearum in Henan province, the toxicity of metconazole against three randomly selected isolates (JY2208, HB2201, and XC2116) at different developmental stages was determined from 219 isolates tested. The combined toxicity of metconazole with prochloraz, phenamacril, fluazinam, and fludioxonil against isolate JY2208 was determined according to the mass ratio of 5 : 1, 3 : 1, 1 : 1, 1 : 3, 1 : 5. The indoor control efficacy of metconazole against FCR was determined by the wheat coleoptile inoculation method. The results showed that the average EC50 values of mycelium growth, sporulation quantity, spore germination, and germ tube elongation of three isolates were (0.0397 ± 0.0035) μg/mL, (0.9549 ± 0.1152) μg/mL, (0.6114 ± 0.0393) μg/mL, and (0.0235 ± 0.0015) μg/mL, respectively. The EC50 values of metconazole, inhibiting mycelium growth of 219 isolates of F. pseudograminearum, ranged from 0.0207 to 0.0839 μg/mL, with an average value of (0.0406 ± 0.0114) μg/mL. The sensitivity frequency distribution was a continuous single-peak curve, which could serve as the baseline sensitivity of F. pseudograminearum to metconazole in Henan Province. The synergy ratios (SR) of metconazole combined with prochloraz, phenamacril, fluazinam, and fludioxonil ranged from 0.51 to 2.32. Different combinations and ratios of the mixture demonstrated either additive inhibition or synergistic inhibition efficacy. These results indicated that metconazole can be used in combination with prochloraz, phenamacril, fluazinam, and fludioxonil. Metconazole and fluazinam, with a mass ratio of 5 : 1, exhibited the strongest synergistic inhibition effect, achieving the maximum synergy ratio, with an SR of 2.32. Under laboratory conditions, the combination of 8% metconazole suspension and 50% fluazinam suspension, with the active ingredient of mass ratio of 5 : 1, achieved 100% control efficacy at the concentration of 80 μg/mL. These results could provide a basis for controlling the Fusarium crown rot caused by F. pseudograminearum. [ABSTRACT FROM AUTHOR]