Epidemiology of Septoria Tritici Blotch in the low/medium rainfall zones of the Southern region to inform IDM strategies

Background

Septoria tritici blotch (STB) is a foliar fungal disease of wheat that can cause yield losses of up to 50% in susceptible varieties in conducive years. Recent surveillance and grower/adviser reports have identified STB as one of the most prevalent foliar diseases impacting on wheat productivity in the Southern Region. The increased incidence and distribution of the disease is largely due to current intensive farming practices, including no-till and stubble retention, which have led to inoculum build-up. Additionally, the STB pathogen has the potential to rapidly evolve with the recent reports on fungicide resistance/insensitivity development in its populations both in Australia and overseas. Through GRDC investments, extensive research has been conducted into the disease lifecycle and epidemiology in the high rainfall zone (HRZ). The knowledge gained from the investments have been used to develop integrated disease management (IDM) strategies for STB in the HRZ. While the epidemiology of STB is well-understood in the HRZ, information on the disease lifecycle and factors leading to epidemic in the medium and low rainfall zones (MRZ & LRZ) is limited. This fundamental information is required to allow for the development of IDM that is specific for the regions. Currently, growers in the MRZ and LRZ are using the IDM strategies that were developed for HRZ by applying pre-emptive fungicides prophylactically to manage STB. Given the differences in the environmental conditions and farming systems, this practice is unlikely to be effective and economical. Key Investment Target 3.3 identified STB as a priority focus disease and the strategy emphasizes the importance of understanding the biology and ecology of priority disease life cycle, dispersal, survival and distribution characteristics to inform management strategies.

Investment description

This investment will provide new knowledge of Septoria tritici blotch (STB) epidemiology and pathogen biology under MRZ and LRZ growing conditions and farming systems. The research outcomes will inform the development of IDM strategies to manage STB that are specific to the MRZ and LRZ in the Southern region. GRDC seek a suitable applicant to provide the research of STB epidemiology and pathogen biology under MRZ and LRZ growing conditions and farming systems and to develop practical and cost-effective integrated disease management strategies for STB in medium and low rainfall zones of the Southern region.

Expected Outcomes

By 2024, growers and advisers in the low and medium rainfall zones of the Southern region will have access to best practice integrated disease management strategies for STB specific to each rainfall zone. Growers and advisers will have a resource that informs on farm decision-making regarding the management of STB specific to their rainfall zone conditions and farming systems.

Outputs

Output 1 By June 2024, a technical report detailing the epidemiology of Septoria tritici blotch in wheat grown in conditions of the medium and low rainfall zones of the Southern Region.

Description

Research will determine

• the impact of inoculum loads present in stubble, volunteers and other host plants,
• stubble management, including pathogen survival periods, pathogen dispersal in standing and slashed stubble,
• environmental conditions that lead to spore maturation and release
• temperature, moisture, rainfall events impacting on the pathogenicity,
• effect of plant growth stages on susceptibility,
• pycnidia spore and ascospore development and latent periods.

Output 2 By June 2024, practical and cost-effective integrated disease management strategies for STB in the LRZ and MRZ will be developed and made available to growers and advisers in the Southern Region.

Description

STB IDM strategies will be developed for the Southern Region MRZ and LRZ. Trials will be developed in consideration of current regional practices.STB IDM strategies will include as a minimum:

• Fungicide application; timing, different mode of actions and with or without seed dressing
• Stubble load management
• STB resistant/tolerant varieties
• Sowing time
• Crop and variety rotations

To ensure consistency, all field trial sites will be designed in consultation with SAGI South.For full details on the ATM, including selection criteria and any associated attachements as as information on any Questions and Answers relating to the ATM, visit