When Leon Hodgson decided to embark on a PhD in crop disease research three years ago, he had more to lose than most – an established career as a research assistant and a full-time wage, and he had a family to support.

But the 46-year-old also had a plan that would allow him to set his sights on a long-held goal of running his own research project and forging a stronger career in a field of study he enjoys.

In 2017, Leon was working as a research assistant in fungicide resistance at the Centre for Crop and Disease Management (CCDM), a national research centre made possible through co-investment by GRDC and Curtin University.

In a role where he was working hard to support other people’s projects, Leon decided it was time to develop the skills needed to take on his own project, applying for and receiving a grains research scholarship funded by the Western Australian Department of Primary Industries and Regional Development (DPIRD) that would be the catalyst for a four-year journey towards a PhD.

The project, supported by co-investment by DPIRD and the CCDM, focuses on ways to help barley growers better manage the risk of fungicide resistance in Pyrenophora teres f.sp. teres (Ptt), the damaging fungal pathogen that causes Net form of net blotch (NFNB) in barley.

Building on previous work

About to head into its fourth and final year, the PhD project aims to build on previous knowledge and research around NFNB fungicide resistance.

Work by the CCDM’s fungicide resistance team first confirmed reduced sensitivity to commonly used Group 3 demethylase inhibitor (DMI) fungicides in Ptt in southern WA in 2013, with resistance being detected in multiple locations across much of the state’s barley growing areas since then.

Research and analysis has been ongoing since, with Leon’s PhD project aimed at taking understanding of the spread of fungicide resistance to another level by shedding light on the gene flow within the landscape for genes associated with fungicide resistance in the NFNB-causing pathogen.

According to Leon’s associate supervisor, DPIRD plant pathologist Geoff Thomas, the information being collected will be vital in helping growers and researchers better manage the pathogen’s spread.

“Fungicide resistance in Net blotch – in both Net form and Spot form – is something we are increasingly having to contend with, especially in WA, so Leon’s work will be an important contributor to our knowledge and capacity for management,” Mr Thomas says.

“Given the prevalence of barley pathogens over the past five to 10 years, his research and the insights it offers us into how fungicide-resistant pathotypes spread within the landscape will be vital to helping us develop the tools and advice to manage the spread on a regional scale.”

CCDM director Professor Mark Gibberd says Leon’s PhD work plays an important dual role in supporting the Australian grains industry, not only delivering research outcomes to growers but also building capability and connections between scientists and the industry they are working to support.

“The CCDM has a strong focus in supporting skill development and ensuring PhD students like Leon develop the hands-on skill and learning in both the lab and the field, so they can then take those skills forward, interact with industry, interact with growers and become a core part of the work being undertaken to improve on-the-ground outcomes in crop protection,” Professor Gibberd says.

Over the first three years, Leon’s research has followed two distinct approaches.

The first two and a half years were spent collecting and analysing extensive green phase (in-crop) and off-season (stubble) samples from barley crops in paddocks across a 20-kilometre array in WA’s northern-central grainbelt.

Fungicide resistance researcher Leon Hodgson has developed his skills in order to take on his own research project. Photo: Carole Kerr

Leon’s goal was to examine the distribution of resistance to DMI fungicides between paddocks and determine the change in the resistance frequency through time.

“This part of the project provided the opportunity to see how far and how fast the NFNB resistance could move under normal agronomic situations. The study allowed me to follow how that changes across a farming landscape over two successive years, as well as provide insight into how it reacts to different crop rotations,” Leon says.

In 2020, the focus shifted to a large, more-controlled intra-paddock trial where Leon could not only continue to observe the gene flow of fungicide resistance in the NFNB pathogen but, importantly, test different management strategies and treatments to determine how best to control the resistance spread.

Field work

This meant many weeks of field work, monitoring the spread of the pathogen across a large area and collecting hundreds of bags of barley leaf samples to take back to the lab for analysis.

“The concern for growers is to have fungicide-resistant pathogens flowing across their paddocks, so the key to this trial is to determine the scale of the movement,” Leon says.

“From this, we can then identify what management strategies could be applied to try and reduce any flow risk.”

CCDM project leader Dr Ayalsew Zerihun is Leon’s primary supervisor and has been helping guide him through his PhD since the start of the study.

“Leon’s work takes a different approach to usual field sampling. Most of our prior knowledge of resistance spread has come from point sampling of leaves, which meant we were missing out on detailed understanding of the large inter-regional distribution and flow of DMI resistance genes in the NFNB pathogen,” Dr Zerihun says.

“We’re hoping at the end of next year when Leon’s study reaches a conclusion we will have more-detailed field data on the roles of different crop management practices in either facilitating or restricting resistance spread and be able to better influence grower practices as a result.”

The next 12 months or so will see Leon embedded in the lab testing samples, analysing data and tackling the many months of reporting and write-up usually associated with a PhD.

He will not be the only one in the family hitting the books, with partner Laura in the final stages of a teaching degree at Curtin University and children Bella (15) and Jax (nine) busy with studies of their own.

“There’s no doubt taking on a PhD has been a huge task, but I feel incredibly fortunate to have been offered the grains research scholarship and had the support of DPIRD and the CCDM to be able to do it over a four-year timeframe,” Leon says.

“It has been amazing to take on a project that is a great blend of agronomy and molecular work and with the finish line in sight I’m not only excited about what this opportunity provides for my future career in research but also, importantly, being able to present and share some really valuable fungicide-resistance outcomes with growers and industry.”

View a CCDM video about Leon's work.