Effect of dose rate and mixture on selection for reduced sensitivity to triazole fungicides in Mycosphaerella graminicola

摘要

The effects of varying doses of fungicides alone or in mixtures, on selection for triazole resistance were examined under field conditions. The triazole fungicide fluquinconazole with the strobilurin fungicide azoxystrobin as a mixture partner were the fungicides tested. Inoculated wheat plots with a known ratio of relatively sensitive to resistant isolates of the leaf blotch fungus Mycosphaerella graminicola were sprayed with fungicides and sampled some weeks later. Selection for fluquinconazole resistance was greater in proportion to the dose up to one-half of the full rate. Higher doses were not tested. There was no measured change in selection for triazole resistance due to the addition of the mixture partner azoxystrobin.