Understanding fungicide resistance in powdery mildew, downy mildew and botrytis

Investigations over the last four years into the incidence of fungicide resistance in powdery mildew, botrytis bunch rot and downy mildew have shown that with some fungicides resistance is widespread (e.g. QoI* in powdery mildew), whereas others are less common (e.g. DMI# in powdery mildew) or occur rarely (e.g. mandipropamid in downy mildew). Some populations of Botrytis are now resistant to more than one fungicide group. Further research is vital to relate the phenotypic and genotypic laboratory results to field performance. For effective resistance management it is critical that growers adhere to the recommended strategies and minimise exposure to at-risk fungicides.