Development of regional disease risk models for fungal diseases of pyrethrum (PY20000)
What’s it all about?
This project is investigating the environmental conditions that drive tan spot and ray blight outbreaks in pyrethrum. These diseases represent a major risk to yield and the industry’s ability to consistently meet market production requirements. Managing for disease is a major financial and environmental cost, and any effort to reduce those costs without major yield losses would be beneficial for pyrethrum growers.
A range of research activities are being undertaken and their results will be used to develop models that identify the relative risk associated with cropping regions and seasons. This information will be used to create a framework for industry decisions regarding frequency and timing of fungicide applications in pyrethrum.
This approach will ensure that high-risk regions are given adequate protection from disease losses but will also lead to an overall reduction in control costs for the industry by reducing fungicide sprays in low-risk regions and seasons.
The research for this project will fall into three areas:
- Climatic effects on disease. A series of controlled environment experiments will be conducted to examine the conditions that favour spore formation, spore germination, leaf infection and host colonisation.
- Regional differences in pyrethrum diseases. Regional differences will be monitored from autumn to early summer in both 2021 and 2022.
- Relationships between disease pressure and yield loss. Field data will be collected from field crops across three growing seasons.
The data obtained during the research activities will be combined to develop disease risk models for the impact of tan spot and ray blight on pyrethrum yield.
From winter to early summer 2021, monitoring of the timing of foliar disease in commercial cropping was conducted at six sites spread across three distinct cropping regions across NW Tasmania, with additional monitoring conducted at one site in Victoria. Data is being collated for analysis with further data to be collected in 2022.
Data on the impact of key foliar diseases was also collected from two replicated trials, each conducted at two sites in the 2021/22. A summary of the data collected is available in the SFT report.
Additionally, a replicated greenhouse experiment was conducted in late 2021 to supplement the data collected from field sites. Plans to duplicate this trial in 2022 is underway.
Work has progressed to focus on the project’s intermediate outcome: Improved understanding of the epidemiology of tan spot and ray blight with specific reference to the environmental conditions that favour outbreaks.
- Field monitoring of fungal diseases in different pyrethrum growing regions was initiated at 21 sites across northern Tasmania and Ballarat in Victoria. The trials are designed to measure regional and climatic impacts on the incidence and severity of tan spot and ray blight.
- Laboratory studies to estimate the impact of temperature and light on fungal spore formation were conducted, with further work planned to provide complementary data to field observations.
- In late winter 2021, research studies to measure the impact of these fungal diseases on pyrethrum crop yield were also started in collaboration with Botanical Resources Australia. A further three sites will be established in October 2021.
- Research studies are planned to continue into 2023 to enable construction of disease risk models for improved and more efficient management of these diseases.
It is now understood that spore formation by the major fungal pathogens of pyrethrum require mild environmental temperatures and that this is enhanced by light. This project will continue to collect data to build on this knowledge over the next 18 months.
This project was a strategic voluntary levy investment in the Hort Innovation Pyrethrum Fund