Most Australian apple varieties are highly susceptible to apple scab, caused by the fungus Venturia inaequalis, which can require several fungicide applications to manage – adding to production costs and the risk of developing fungicide resistance.
The four-year project is a collaboration between the Department of Primary Industries and Regional Development (DPIRD), Curtin University’s Centre for Crop and Disease Management (CCDM) and the Solving Antimicrobial Resistance in Agribusiness, Food and Environments (SAAFE) CRC.
The collaborative project will use DNA analysis and new monitoring tools to help devise orchard management strategies to reduce the fungicide resistance risk and help plant breeders identify genetic selections for future tolerant varieties.
The first component of the research has commenced to assess and verify the prevalence of apple scab and fungicide resistance across Australia.
Apple growers across the country are called upon to contribute to the research by providing samples of apple scab infected material for analysis.
DPIRD senior research scientist Andrew Taylor encouraged growers to send samples as soon as possible, as the window for apple scab symptoms was closing fast.
“We really need growers’ help by providing infected leaf or fruit samples to help establish the prevalence of fungicide resistance in the apple scab types found across Australia to progress the research,” Dr Taylor said.
“Free sampling packs are available to growers which contain all the information required for collection, including the use of a specifically designed digital app.
“The app allows for all the necessary information to be collected at the exact sampling point – saving growers time and providing traceability for each individual sample throughout the testing process.”
The fungal cultures will be assessed against different groups of registered fungicides to identify resistance or loss of efficacy, providing vital data to inform management strategies that reduce the risk of resistance.
Cultivars from the Australian National Apple Breeding Program’s orchard, at DPIRD’s Manjimup Research Station, will also be screened for disease resistance during the project.
Dr Taylor said this information would help plant breeders create new high performance apple varieties that are resistant to apple scab and require fewer or no fungicide applications, against the disease.
“To date, apple breeding has focused on taste, storage, visual appeal and yield,” he said.
“This research will assist the Australian National Apple Breeding Program to include apple scab disease resistance in selections by identifying suitable cultivars that can be used as parent crosses.
“While it takes about two decades to develop a new cultivar for release, this research will provide a big leap by identifying high potential cultivars in the early stages of a breeding program.”
Another component of the research will evaluate the effectiveness of existing commercial decision support systems, like digital apps, that provide advice on the lifecycle of apple scab in specific orchards and potential management measures.
Spore traps will be installed on growers’ properties in the Perth Hills and in the South West to validate the information captured by the decision support systems.
“These systems have proven to be effective in reducing applications and the risk of fungicide resistance developing,” Dr Taylor said.
“The current decision support systems have been created in the northern hemisphere. This project will examine whether the modelling used in those systems is adequate for Western Australian growing conditions or if further calibration will be required.”
Progress on the research will be shared with growers and industry in future field days and workshops.
Free sample packs can be obtained from emailing applescab@dpird.wa.gov.au.
