Fungicides were applied to minus-disease plots at GS 31 and GS 39. Plus-disease plots were inoculated at seedling and mid-tillering stages using a conidial suspension in water applied as a spray. In South Australia, trials were located at Hart Field Site and Booleroo Centre. Treatments were replicated six times and were blocked by disease treatment, with plot size of 10m x 1.5m. Trials were a split-plot design with disease-inoculated plots (‘plus-disease’) and disease-controlled plots (‘minus-disease’) for each variety. Varieties and STB resistance ratings were as follows: LRPB Impala SVS, Calibre S, Scepter S, Razor CL Plus S, Hammer CL Plus MSS and LRPB Lancer MS. Ratings for stripe rust and powdery mildew were taken into consideration as well. Six varieties were selected based on their disease resistance ratings to STB. In 20, SARDI in conjunction with Agriculture Victoria and the GRDC have conducted field trials in low and medium rainfall zones to quantify yield losses in wheat varieties. Typically, yield losses are observed in the high rainfall zones (HRZ) of the state, but seasons such as 2022 were conducive to yield losses in low and medium rainfall zones (LRZ, MRZ respectively). The disease is spread via rain splash and infection on the top three leaves is a driving factor for yield loss. Septoria tritici blotch (STB) was prevalent across the state in 2022, with higher-than-average spring rainfall causing substantial disease development in some areas. ![]() use of support tools such as the StripeRustWM App.proactive foliar fungicide applications.up front fungicide applications – in furrow, seed dressings, coated fertiliser.variety selection – avoid susceptible varieties.A successful stripe rust integrated disease management plan will include: Growers should be prepared for the rust epidemic to begin early in the season and have an integrated disease management plan ready to implement. Green bridge control will be essential in the lead up to sowing, as volunteers host the rust inoculum. The stripe rust disease risk is expected to be high in 2023 with high inoculum loads across the state from the 2022 season. Paddocks that avoided susceptible varieties, had fungicides applied at seeding, and had timely foliar fungicide applications achieved the greatest stripe rust control. Wet cool conditions for the remainder of the season maintained a high level of disease pressure from stripe rust in susceptible varieties. Stripe rust epidemics began early in these growing regions in 2022 and South Australia followed suit with the first stripe rust report in late July. Summer rainfall through 20 caused flooding in QLD and NSW, driving a green bridge between the growing seasons and allowing stripe rust inoculum to proliferate. ![]() Stripe rust caused substantial damage and yield loss to wheat crops in the eastern states in 2022. Australian rainfall deciles for 2022 showing above average rainfall in South Australia, Commonwealth of Australia 2022, Bureau of Meteorology. Integrated disease management strategies were particularly important in this season with variety selection, proactive fungicide management and non-chemical farm management (for example, green bridge control, crop rotation and stubble management) providing the best opportunity for effective disease control.įigure 1. Many paddocks experienced yield losses, reduction in grain quality and/or grain defects from disease pressure. ![]() These conditions were very conducive for foliar disease development and wheat crops particularly suffered from powdery mildew, stripe rust and septoria tritici blotch. Wet conditions continued late into spring and early summer affecting conditions during grain fill and harvest. The 2022 growing season in South Australia received above average rainfall in most areas of the state (Figure 1). ![]()
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