Testing biological controls in the lab: setting up in vitro bioassays

Research led by Agriculture Victoria pathologist Dr Tonya Wiechel is evaluating promising biological control agents identified in global research, testing them against disease isolates collected from Australian orchards. 

Biological control offers an environmentally friendly alternative to chemical pesticides, using natural organisms to suppress plant pathogens such as apple scab (Venturia inaequalis), pear scab (Venturia pirina) and Phytophthora root rot. PIPS 4 Profit research into new biological control options for apple and pear diseases aims to deliver sustainable tools that help growers reduce reliance on chemical inputs while maintaining fruit quality and yield. 

In vitro bioassays: the starting point

The first phase of the project is underway and involves laboratory bioassays using agar plate methods. These in vitro tests are allowing researchers to observe how biological agents interact with scab and Phytophthora isolates collected from orchards in Victoria, New South Wales, Tasmania, South Australia and Western Australia. The goal is to identify which biological agents best inhibit pathogen growth. 

Promising agents will be moved onwards to potted tree trials in the next year, giving researchers a better picture of their effectiveness in protecting plants under near-field conditions. 

Plant pathology researcher Tonya Wiechel provided guidance to Noah Osborn during his Agriculture Victoria internship recently.

Engaging the next generation

An exciting aspect of this work is the involvement of University of Melbourne Bachelor of Agriculture students Noah Osborn and Rebekah Lui, who undertook internships with Agriculture Victoria. Both students gained hands-on experience in plant pathology research, contributing to the setup and monitoring of the in vitro bioassays.  

“It’s been really exciting to work as part of this project for the apple and pear industry,” Noah said. “Hopefully our research contributes to sustainability of the industry going forward.” 

The involvement of students highlights the value in giving young scientists the opportunity to apply their skills in real-world agricultural research and connect the importance of this work to the beneficiary industry. Including students at the degree level allows them to consider early on what future opportunities might look like for them, such as a master’s degree or PhD.  

Not only has this collaboration strengthened the project’s capacity, but it also helps foster the next generation of plant health experts. By working alongside experienced scientists, Noah and Rebekah learnt how science directly supports growers and industry through innovation in sustainable disease management. 

Building sustainable solutions

By focusing on biological control, this project supports the apple and pear industry’s drive to reduce reliance on chemical inputs and strengthen integrated pest and disease management. Collaboration with partners, including Pomewest, NSW DPIRD, Fruit Growers Victoria and the Tasmanian Institute of Agriculture, ensures research outcomes are nationally relevant and directly beneficial to growers. 

With continued investment and the support of young people entering the field, the potential for biological control agents to become valuable tools for growers is growing stronger. This research marks a step toward more resilient orchards and a more sustainable future for the Australian apple and pear industry. 

Further information 

Watch this video featuring Tonya and Noah: https://www.youtube.com/watch?v=awYKMZeyNmk  

Read “Biological control options for key apple and pear pathogens”, apal.org.au/biological-control-options-for-key-apple-and-pear-pathogens/ 

Acknowledgement 

The PIPS 4 Profit Pest and disease management (AP22001) project has been funded by Hort Innovation using the apple and pear research and development levy, contributions from the Australian Government and co-investment from Agriculture Victoria. It is supported regionally by the Tasmanian Institute of Agriculture, Pomewest and NSW Department of Primary Industries and Regional Development. Hort Innovation is the grower-owned, not-for-profit research and development corporation for Australian horticulture. 

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