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Published: 15 Apr 2020

Dharushana poppy phd

A PhD student’s research will help support the prosperity of Tasmania’s poppy industry which has been battling a relatively new disease for the past six years - systemic downy mildew.

A PhD student’s research will help support the prosperity of Tasmania’s poppy industry which has been battling a relatively new disease for the past six years.

Dharushana Thanabalasingam moved from Sri Lanka in 2018 to join the Tasmanian Institute of Agriculture (TIA) and pursue a PhD to better understand a disease of opiate poppy known as systemic downy mildew.

TIA is leading the scientific response to the disease since its discovery in Tasmania in 2014 which threatened the viability of the industry and shook grower confidence. TIA is also working closely with industry to implement recommendations around best practice management of the disease.

Dharushana's PhD research aims to gain a greater understanding of the relative importance of inoculum sources that spread systemic downy mildew.

“My main aim is to identify the roles played by the critical inoculum sources to spread systemic downy mildew disease in opiate poppies. The inoculum sources include seed, soil and air and my aim is to find out which factor plays the biggest role in spreading the disease and how best to target it,” Dharushana said.

“The findings of the research will inform effective management strategies which are essential to ensure the long-term viability of this important industry. This could include advice around the most effective times to apply fungicide, further insight about crop rotations, or possible biocontrol options.”

Poppy Growers Tasmania Chief Executive Keith Rice said one of the strengths of TIA’s research is that it is conducted in collaboration with local farmers and poppy processors, ensuring that the industry is working together for a long-term and practical solution to the issue.

“The Tasmanian poppy industry has its foundations clearly anchored in the application of sophisticated science and technology to a natural plant. It has faced and conquered numerous challenges since its inception 55 years ago, and this research is essential to the ongoing success of this globally important industry,” Mr Rice said.

In mid-February, Dharushana was at TIA’s Forthside Research Farm to harvest a trial crop of poppies. The trial included two different treatments – one which was subjected to possible infection from soil, seed and air, and another which was sprayed regularly with fungicide to reduce the possibility of infection from airborne sources.

Healthy plants were also grown in greenhouse conditions using potting mix with pathogen-free seeds. Dharushana brought the healthy plants to the field trial prior to each sample collection, leaving them in the field for a week to assess the impact of air borne spores without the additional impact of infected seed or soil.  Disease progression in the field trial was also monitored and recorded throughout the experiment.

“I am so excited to find out the results from this trial as it is a major part of my PhD project. I am harvesting the poppies to check for any differences between the two treatments over time, including variations in yield and alkaloid content,” she said.

“This trial will help to identify whether it is seed, soil or air that plays the major role in spreading the disease.”

The PhD project has included other experiments, including greenhouse trials looking at the role of environmental conditions such as soil type, soil moisture and soil temperature in how the disease is spread via seed and soil and the potential plant growth stage for air-borne disease spread.

Dharushana’s project is supervised by TIA Senior Research Fellow Dr Jason Scott as part of the Australian Research Council funded project ‘Developing a risk management system for systemic downy mildew of opium poppy’.  This work is also supported by Tasmanian Alkaloids, Sun Pharmaceuticals, Poppy Growers Tasmania and the Tasmanian Government.

“Dharushana is extremely passionate about her research and its potential to provide positive outcomes for industry. Systemic downy mildew puts a significant cost on growers, not just in crop losses but also in the costs of minimising those losses.” Dr Scott said.

“Dharushana’s work will help identify the key points in the disease cycle so that growers can be more targeted with their efforts to control the disease, which should make these efforts more effective.”

The project is expected to run until early 2021 and Dharushana's thesis will summarise research findings.

TIA is a joint venture between the University of Tasmania and the Tasmanian Government.

This article also appeared in Tasmanian Country newspaper on 10 April 2020.