A new diagnostic tool gives growers the upper hand in controlling disease
A mushroom industry-funded project has delivered a commercially available early disease detection service which has revolutionised the way growers manage disease.
Growers can now identify disease early, whether in compost, grow room, or the crop itself, facilitating timely action to manage diseases and minimise losses.
Samples being prepared for PCR testing
For example, the system can identify Trichoderma aggressivum, a species of green mould that is highly damaging to yield but nearly impossible to distinguish visually from other less serious green moulds.
Interestingly, the PCR test used to detect Trichoderma uses the same technology as the gold standard PCR test for detecting COVID-19.
The PCR test can also identify Dry Bubble (Lecanicillium fungicola), Cobweb (Cladobotryum sp.) and Bacterial Blotch. All four diseases are included in the same testing ‘panel’, meaning that a single test can detect any of the diseases above in any one sample provided.
The results from a single sample give a positive or negative for a range of species (see Table 1), as well as an indication of how much disease is present.
Quick turnaround of test results, early detection before symptoms are evident, and cost-effectiveness are all major benefits of the new testing service.
The PCR-based testing service was developed by a Hort Innovation project (MU12007) and is now fully operational.
The development team was led by Associate Professor Michael Kertesz from the University of Sydney. Partners included AusDiagnostics, who provided the PCR delivery platform, and disease experts Judy Allan and Dr Warwick Gill. Trials were carried out by the Marsh Lawson Mushroom Research Unit (MLMRU).
The project was managed by Applied Horticultural Research (AHR) who are now also providing the testing service commercially from their Sydney laboratory.
Trichoderma (left) and dry bubble (right) are just two of the diseases that can be tested for using the PCR testing service
The diseases which can be detected using the PCR testing service developed by Hort Innovation project MU12007 are:
Cobweb - Cladobotryum mycophilum (Hypomyces odoratus)
Lecanicillium spp.
Dry bubble - Lecanicillium fungicola (Verticillium fungicola)
Trichoderma spp.
Green mould - Trichoderma aggressivum
Bacterial blotch - Pseudomonas tolaasii and Pseudomonas gingeri
Testing and control measures on farm are effective at controlling disease
The mushroom disease testing service has already proved popular, with over 5,000 samples processed since August 2020.
As well as identifying disease, testing after cookout can provide vital information on whether control measures taken at the farm have been effective.
AHR has seen some encouraging trends in the testing results, showing that PCR testing for disease, coupled with corrective action, is effective at controlling disease.
AHR principal, Dr Gordon Rogers says “Farms using this service see a steady decline in positives for diseases they are targeting.”
“This means the control measures on farms are working, and testing is confirming their effectiveness.”
AHR employee Samali Perera runs mushroom samples through the PCR machine
How to get your samples tested
PCR testing, developed during the Hort Innovation project, is now being offered as a commercial service by AHR, using a methodology commercialised by AusDiagnostics.
The PCR technique is highly sensitive at detecting diseases. A sample containing even the smallest amount of the disease can usually be detected before any symptoms are evident in the crop.
Very importantly, the way the sample is collected is critical.
A video produced by Judy Allan and Warwick Gill demonstrates how to collect samples for disease testing from growing rooms, equipment, work areas, mushroom caps and compost. Click here to view the video or visit the AGORA website for both the video and appropriate control measures.
To test for the presence of Trichoderma, Cobweb, Dry Bubble or Blotch disease, send your samples by express post to the AHR diagnostic laboratory in Sydney to:
Applied Horticultural Research
PO Box 917 Alexandria NSW 1435
For more information on how to collect and send samples to the laboratory, visit the AHR website https://ahr.com.au/mushroom-disease-diagnosis-service
This project has been funded by Hort Innovation, using the mushroom research and development levy and contributions from the Australian Government. Hort Innovation is the grower-owned, not-for-profit research and development corporation for Australian horticulture.
