emerging plant pests

There are two important reasons why pests including Emergency Plant Pests (EPPs) can become established in urban areas and spread to nearby horticultural or agricultural areas. First, urban dwellers usually purchase large quantities of goods and services from a variety of sources and locations, and so are potentially exposed to a wide a range of pests. Second, urban areas have a high density of exotic gardens and other resources that allow newly introduced pests to become established. Surveillance for EPPs in urban areas is therefore an important element of any system that aims to prevent the establishment of pests in rural and agricultural areas.

Research outcomes

This project looked at the contribution that passive and targeted (or active) surveillance can make to the on-ground management of Emergency Plant Pests (EPPs). EPPs can become established in urban areas and spread to nearby horticultural or agricultural districts. Surveillance for EPPs in urban areas is an important element of any system that aims to prevent the establishment of pests in rural and agricultural areas.

The benefits of a combined program of targeted and passive surveillance for an EPP was investigated. A combination of targeted and passive surveillance has kept the European wasp — a major pest of urban areas and horticulture in south-eastern Australia — from establishing a viable population in Western Australia for the last 30 years.

Targeted surveillance using lures and passive approaches relying on public reporting are complementary techniques that can prevent establishment and spread of European wasps.

Research implications

This project illustrated that a multi-pronged surveillance approach may be needed to control the spread of EPPs — in this case study, infestations of the European Wasp in Western Australia (WA).

For more than 30 years the Department of Agriculture and Food of Western Australia (DAFWA) has been using a combination of passive and targeted surveillance techniques to detect and then destroy wasp nests to control the European wasp.

A major challenge for the surveillance program is that if a nest is missed during one summer it may overwinter allowing the release of new queens. The population of wasps and their colonies can therefore exhibit explosive growth within a single summer.

Additionally, with hibernating wasp queens being continually imported into WA from rail or road transport freight there is an ongoing need for this cost effective surveillance program to continue.

Standard use of GPS devices (in Personal Digital Assistants or other hardware) would reduce the time required for data cleaning and manipulation and facilitate faster, more prompt analysis of surveillance data sets.

Acknowledgements

Thanks to Darryl Hardie and Fred Ramsden from DAFWA and the staff from the Pest and Disease Information Service (PaDIS).

There are hundreds, perhaps thousands, of invasive species that have the potential to arrive and establish in any particular region or country. Identifying which species are more likely than others to invade and establish is extremely difficult, yet the capacity to do so is vitally important to the biosecurity of a nation.

Currently, government agencies consult industry stakeholders and technical experts, as well as published data to generate a pest risk assessment for a particular insect pest. While this can be valuable for many reasons, any estimate of risk is ultimately subjective. An alternative is to use a more quantitative modelling approach to generate more objective estimates of risk. One modelling approach is to utilise a Self Organising Map (SOM), which is a type of artificial neural network.

Research outcomes:

Self organising maps (SOM) are a useful tool for ranking species by their likelihood of establishment. We have tested this tool and found it to be both resilient to significant errors in the distributional data (up to 20%) and very reliable in its predictions of which species will and wont invade a region.

Research implications:

SOM would be a valuable tool to integrate into the current biosecurity practices. It could be used initially to screen a large number of potential invasive species down to a more manageable number. The rankings generated by SOM for this reduced list could then be included in the consultative process currently used to prioritise pest lists.

Acknowledgements:

The project team would like to thank the following government agencies for their gracious support of the project: Department of Agriculture, Fisheries and Forestry – Bureau of Rural Science; Department of Agriculture and Food Western Australia, Department of Primary Industries Victoria; the South Australian Research and Development Institute; New South Wales Department of Primary Industries; Northern Territory Department of Primary Industries, Fisheries and Mines; the Tasmanian Department of Primary Industries and Water; and the Queensland Department of Primary Industries and Fisheries.

We would like to acknowledge the help and advice of the following people and organisations: Richard Mack, Andy Sheppard, Paul De Barro, Matthew Thomas, CAB International, Tak Ikeda, Roger Magarey, Dan Fieselmann, Karl Suiter, Sharyn Taylor, Nadiah Kristensen, Simon Barry, John LaSalle, Marianne Horak, Rolf Oberprieler, Peter Gillespie, Bob Forrester, Alice Wells, Darren Kriticos, Felix Bianchi, Gary Fitt, Roger Shivas, Mike Watts, Greg Baker and Marc Poole.

Thank you very much to CRCNPB’s Delivery and Adoption Program and CSIRO Computational and Simulation Sciences Transformational Capability Platform for their generous support of the Technologies Enhancing Biosecurity Preparedness workshop held at the Rydges Lakeside Canberra Hotel on the 21st May 2009. We particularly thank John Taylor (CSIRO), Cain Roberts (CRCNPB) and Melanie Hay (CRCNPB) for their help in arranging the workshop. We would also like to thank all who participated and helped to make it a success, including Jeanine Baker (DAFF – BRS), Joanne Banyer (ABIN), Mike Cole (OCPPO), Andrew Copp (DEWHA), Daniel Fieselmann (USDA – APHIS), Neil Grant (DAFF – BA), Don Gunusekera (DAFF – ABARE), Takayoshi Ikeda (Lincoln University), Jon Knight (Imperial College London/PRATIQUE), Gwenael Leday (Lincoln University), Simon McKirdy (CRC NPB), Steve McMahon (ABIN), David Newth (CSIRO), Bill Roberts (DAFF – BA), John Sandow (CRC NPB), Andy Sheppard (CSIRO), John Taylor (CSIRO), Sharyn Taylor (PHA), Louise Van Meurs (DAFF – BA).