NGN - Management strategies for wheat powdery mildew in southern NSW - Validation and extension

Wheat powdery mildew (WPM) can cause up to 25% yield loss in Australia with commonly grown varieties possessing poor resistance, ranging from susceptible to very susceptible (SVS). In the Northern region WPM is particularly problematic in the western lower rainfall areas of NSW in years of higher than average rainfall and irrigated paddocks, though is found throughout the wheat growing regions of NSW.

In the Northern region, shifts in fungicide sensitivity and resistance to both Group 3 (DMI) and Group 11 (QoI) fungicides have been detected in WPM in paddocks across SE, SW, NE and NW NSW. Resistance to Group 3 (DMI) fungicides propiconazole and tebuconazole was detected in NSW and VIC, with frequencies ranging from 50 to 100% of in-field samples. Fungicide resistance to all Group 11 (QoI) fungicides in WPM was first detected in-field in NSW, SA, Tas and Vic Australia in 2019. Detection of fungicide resistance indicates potential inefficacy of these fungicide groups when applied in crop. The alternative fungicide Group 7 (SDHI) has limited registered products for WPM. Resistance management strategies are necessary to prevent loss or reduced efficacy of the fungicide options available to manage this disease.

Fungicide resistance management strategies were previously developed for WPM by Trengove Consulting in SA (SAGIT Project TC120) in 2020 and 2021. The key outcomes of this project highlighted the effectiveness of varietal resistance and the optimal variety by fungicide application strategies as measured by yield gain.

This investment builds upon the findings in the SAGIT Project TC120 as well as a similar investment for the Southern Region (TRE2204-001RTX) to expand the validation and extension of WPM management strategies to areas in the Northern region impacted by WPM.