Fungicide resistance in wheat powdery mildew in NSW and northern Victoria, 2020

Abstract

Key findings • The wheat powdery mildew (WPM) pathogen has a very high risk of developing fungicide resistance. • Resistance to Group 11 (quinone outside inhibitors, QoI) fungicides has been detected across most of the southern growing region (Tasmania, Victoria and South Australia) and was detected in parts of NSW in 2020. • Widespread plant resistance or reduced sensitivity to Group 3 demethylation inhibitors (DMIs) is considered an extremely high risk with a DMI ‘gateway’ mutation detected at very high frequencies across NSW and northern Victoria in 2020. • Careful use and rotation of available fungicide actives will help control the spread of resistance in WPM. • Agronomic practices that minimise disease pressure, reduce the need to apply fungicides. • Good management will help protect the long-term efficacy of current fungicides.