Detection of demethylation inhibiting fungicide resistance in the grapevine powdery mildew fungus, Uncinula necator

Abstract

This thesis investigates the sensitivity of Uncinula necator (Schw.) Burr powdery mildew fungus to DMI (Demethylation inhibiting) fungicides in Australian vinyards. Baseline sensitivities were established for two commonly used DMIs (triadimenol and fenarimol) and a PCR-based assay was developed to detect triadimenol resistence in U. necator on infected grapevine material collected from the field. It has shown that since the introduction of DMI fungicides into Australian vineyards, there has been a shift in sensitivity to triadimenol and, to a lesser extent, fenarimol. This will be useful when developing disease management strategies that reduce and delay the development of resistance to DMI fungicides.