The development of automated, mobile sentinel trap systems for airborne insects and pathogens is just the starting point for the successful iMapPESTS project.

Over the course of six years, it has provided an international proof of concept for an end-to-end surveillance and reporting system designed to help growers protect crops against airborne pests and pathogens.

The project has integrated automated sentinel traps, traditional and new genetic diagnostic techniques and a cloud-based data platform that provides public access reports on target pest and pathogen species.

GRDC contributed $1.8 million to the project, which is a partnership with the Federal Government’s ‘Rural R&D for Profit’ program and six other plant industry research and development corporations (RDCs).

Dr Rohan Kimber, at the South Australian Research and Development Institute (SARDI), led work to develop the trapping and identification processes.

This included mobile sentinel traps for automated sampling of airborne insects and pathogens, the diagnostic identification processes and the connectivity of all data, to feed results into a visualisation platform for users.

End-to-end process

Between 2019 and 2023, iMapPESTS held 44 field trials at sites in New South Wales, Queensland, South Australia and Victoria. Dr Kimber says that as the project progressed, the sentinel traps evolved and automation systems were refined. Twelve different models have been developed.

The smallest sentinels are single purpose, collecting only insects or pathogen samples. The largest models combined traps for both and included two-metre and six-metre suction traps. But all provide for the automated collection and barcoding of samples and capture operational and weather data to accompany samples.

While barcodes are added to sample containers, information was also stored in the cloud, and remained associated with samples as they travelled to laboratories for identification.

Measurement of airborne pathogens was provided by SARDI’s Molecular Diagnostics Centre, while laboratories at both SARDI and Agriculture Victoria Research (AVR) provided the identification process of airborne insect data. These results were added to the cloud platform.

The peak body for the vegetable industry, AUSVEG, led the project’s communication and extension efforts, including the development of the visual dashboard on the project website. Based at AUSVEG, iMapPESTS project coordinator Shakira Johnson says providing publicly available data as part of the end-to-end surveillance system was an essential part of the project.

“AUSVEG established an extension network to raise awareness, build support and promote adoption of the program’s outputs and outcomes across each industry,” Ms Johnson says.

“Key stakeholders, including those in the grains industry, were encouraged, engaged and supported to use the information through activities such as workshops and events. These activities extended the research and development to practical applications.”

Among these applications has been the use of information from the website’s dashboard by grains sector agronomists and growers to make decisions about crop protection programs.

This was particularly the case in 2022, when the sentinel traps in South Australia and Victoria showed significant migration of oat aphid, as well as abundant blackleg, chocolate spot and Septoria tritici blotch spores in the air, affecting local canola, pulse and cereal crops, respectively.

Trials also demonstrated that a network of sentinels placed within a transect of 40 kilometres reported similar levels of airborne diseases within that region – meaning they are able to collect accurate data across wide areas, not just where they are in the immediate vicinity.

Genetic ID developments

AVR research director Professor Brendan Rodoni says the identification of insects using visual inspections is often a bottleneck in surveillance systems and is both labour-intensive and expensive.

Through iMapPESTS, his team at the AVR AgriBio laboratory has developed a metabarcoding approach that can simultaneously identify hundreds – if not thousands – of different insect species at once, collected in a single trap, using automated high-throughput DNA sequencing.

The results are compared against a genetic database established by AVR that includes more than 300,000 reference DNA sequences from around the world, representing more than 100,000 native and exotic species.

On a cost-comparison basis, metabarcoding is expected to reduce the cost of insect identification by an order of magnitude and is nearing the cost of standard single-species PCR tests.

Professor Rodoni points out that while PCR tests can identify a particular target species, metabarcoding identifies all the insects in a sample. On this basis, he says, industries collaborating could potentially pool funding for a single surveillance system that monitors for multiple pests.

The ability of metabarcoding to quickly identify the presence or absence of species is a strength that could assist with ongoing national biosecurity surveillance and providing ‘proof of absence’ of threats to protect Australia’s international market access.

During the trials, metabarcoding quickly identified hundreds of insect species in and around grain crops in the Wimmera district in Victoria. These included a higher number of aphid species compared to morphological examinations, as well as many beneficial insects such as parasitoid wasps of aphids.

Professor Rodoni says this demonstrates the use of metabarcoding as a potential tool to screen for biosecurity threats and endemic pests and for the presence of insects used for biological control.

GRDC biosecurity program manager Callum Fletcher says collaboration across all plant RDCs as part of iMapPESTS was an important part of the project’s success.

“We’re now looking at future collaborations and a second iteration of the project, to see how we can take the work on the sentinel traps and the insights from the diagnostics, and apply these more broadly to help growers,” Mr Fletcher says.

More information: iMapPESTS, @iMapPESTS; Callum Fletcher, callum.fletcher@grdc.com.au

The program (2017–23) is supported by Horticulture Innovation Australia Limited, through funding from the Australia Government Department of Agriculture, Fisheries and Forestry  as part of its Rural R&D for Profit Program, as well as GRDC, Sugar Research Australia, Cotton Research and Development Corporation, Wine Australia, AgriFutures Australia, and Forest and Wood Products Australia.