Soil tests reveal the big picture

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Key points

  • As the range of tests on offer through PreDicta® B expands to include new pathogens, the ultimate aim is to monitor how soil and stubble-borne pests, diseases and beneficial organisms are responding to changes in farming systems and seasonal conditions. This will require new and faster methods to validate tests and develop risk categories for disease or yield loss
  • New ‘tests under evaluation’ will be added to the PreDicta® B report in the 2017-18 season
  • In the future, paddock information will be used to shed light on how changed farming systems, new varieties and seasonal conditions influence the number and type of organisms detected
  • With investment from the GRDC, the Molecular Diagnostics Centre based at the South Australian Research and Development Institute in Adelaide has started work to double its sample capacity and develop faster tests


Fast fact

Increasingly, PreDicta® B results are being used to underpin economic analyses to inform research priorities.

To fast-track the delivery of new test results to growers, the Molecular Diagnostics Centre has developed a series of reporting categories based on population density as part of the GRDC-funded national molecular diagnostics project.

The four categories – ‘below detection’, ‘low’, ‘medium’ and ‘high’ population densities – are based on the results of hundreds of samples tested from across the target region. These categories are not disease or yield loss risk categories, rather they allow growers and their agronomists to benchmark pathogen levels in individual paddocks against the broader cropping region.
A ‘tests under evaluation’ section has also been added to PreDicta® B reports, with several new tests likely to be reported in the 2017-18 season, including tests for the pathogens that cause ascochyta blight of chickpeas (reported in the northern region last season), yellow leaf spot, charcoal rot, Fusarium stalk rot of sorghum and possibly Phytophthora root rot.

Further work may be required to adapt sampling strategies to cater for a broader range of crops. This may involve adding stubble of alternative crops if it is present, rather than just adding cereal or grass stubble.

Automation and computerisation will allow improvements in efficiency, with the aim of including the additional tests within the current pricing structure. To continue to evolve new tests the longer-term challenge will be to develop new molecular technology.

The big picture

Recognised as a National Centre of Research Excellence under the Grains RD&E Framework Implementation Plan, the Molecular Diagnostic Centre’s (MDC) primary focus is to develop high-throughput tests for soil-borne pests and diseases to help the industry and scientific communities manage disease risk, monitor treatment effects in field trials and conduct testing to support market access.

Increasingly, PreDicta® B results are being used to underpin economic analyses to inform research priorities.

Yet, there is so much potential to extract valuable information on the impact of changed farming systems, new varieties and seasonal conditions on the spectrum and numbers of important organisms.

Projects such as the National Paddock Survey are showing the benefit of collating paddock information to identify how cropping systems promote specific pests and diseases. With GRDC investment, the MDC is building its capacity to store paddock information while working with the National Paddock Survey and the National Variety Trials to refine this concept.

In addition, new projects with GRDC investment are exploring the opportunity to monitor spore and insect traps for area-wide surveillance for biosecurity threats and high-throughput capability to monitor incursions of new species. The technology is also expanding into other plant industries, including several vegetable industries, and is being adapted to viticulture and sugar.

GRDC Research Codes DAS00137, BWD00025

More information:

Dr Alan McKay
08 8303 9375