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Contingency planning for plant pest incursions in Australia

Paul Pheloung

Office of the Chief Plant Protection Officer, Australian Government Department of Agriculture, Fisheries and Forestry, GPO Box 858, Canberra, ACT 2601, Australia; e-mail:


Effective planning for plant pest incursions in Australia is founded on: monitoring and surveillance to provide early warning of the arrival of new pests; diagnostics tools and expertise to clearly identify the pest; information systems that define the pest status of the country; and reporting arrangements to ensure knowledge of new incursions is acted on quickly. Contingency planning can be targeted for certain key pests that are clearly a threat and for which an entry pathway can be identified. A generic response framework is also essential to identify, assess and react to incursions as they occur. In Australia, the Australian government is responsible for managing risks at the national borders while seven states and territories must work individually or together to deal with pest problems within the country. The Australian government has a key role in coordinating the response to new pest incursions.


Increasing international trade and travel presents Australia with an ever-growing risk of pest incursions. As an island continent, it has the advantage of physically distinct land borders but its coastline is extensive. Climate zones range from tropical to arid to temperate, providing a wide range of ecosystems in which an incoming pest might find a suitable habitat to become established. The Australian government is responsible for managing risks at the national borders and has a key role in coordinating the response to new pest incursions. The individual states and territories work singly or together to deal with pest problems within the country.

The problem of dealing with pest incursions is a challenging task that demands effective planning and resourcing. Since 1995, hundreds of exotic pest incursion or barrier incidents have been recorded in Australia. Of these, over 20 have been of sufficient concern to warrant a nationally coordinated and funded response with combined expenditure exceeding $A200 million. Others have been managed individually by state or territory governments and/or the affected industries.

Some examples of organisms that have entered Australia and pose particular threats to ecosystems or land-based production are:

Brief case studies of the response to incursions of these organisms are described later in the paper.

Planning for pest incursions

Contingency planning for pest incursions includes many different activities, both scientific (e.g. pest diagnostics and biology) and administrative (e.g. authorization and funding). The activities fall within a spectrum of pre-border, border and post-border quarantine systems:

This paper gives particular attention to offshore activities, surveillance and monitoring, and pest incursion management under the Northern Australia Quarantine Strategy (NAQS), a programme delivered by the Australian Quarantine and Inspection Service (AQIS) and the Office of the Chief Plant Protection Officer. It outlines tools for gathering pest information and developments in the legal and administrative aspects of managing pest risk.

Offshore activities

One of the most important characteristics of Australia’s management of pest incursions is that frequently it begins offshore. Pre-border regional collaboration is an important means of understanding what the pest threats are and then mitigating these threats.

Regional capacity building includes training plant protection Officers in neighbouring countries and facilitating the development and management of collections of plant pests. E-mail and Internet discussion groups also provide a means of enhancing regional knowledge and awareness of pest risks. PestNet, for example, is an e-mail network for the Pacific and Southeast Asian regions providing advice and information on plant protection issues, including quarantine, and linking people in these regions with worldwide specialists.

Collaborative surveys and research projects can improve understanding of the risks posed by a potential pest. NAQS conducts regular surveys of parts of New Guinea and Timor in collaboration with governments of Papua New Guinea, Indonesia and East Timor. The red-banded mango caterpillar is widespread in Southeast Asia, including Papua New Guinea, and has recently been detected in Australia. It is regarded as a serious pest of mango but the biology of the pest is not well understood. The governments of Australia and Papua New Guinea are currently undertaking joint studies on methods of eradicating or at least controlling the red-banded mango caterpillar in commercial mango-producing areas.

Knowledge gained through such activities can provide a measure of the immediate threats to Australia. It also allows carefully targeted post-border surveillance for particular organisms.


Surveillance is an essential element in preventing the establishment or spread of exotic pests, through early detection and managing the response to such detections, and supporting trade where it depends on pest free status. Surveillance may be general, where information on pests is gathered from many sources, or it may take the form of specific surveys to obtain information for specific sites over a defined period of time. Specific surveys may be detection, delimiting or monitoring surveys. These activities are defined in more detail in ISPM 6: Guidelines for surveillance.

In Australia, general surveillance is an important part of NAQS and a related programme, Northwatch, delivered by the Queensland State Government. Other parties and programmes involved include industry, the development of pest awareness (e.g. by publication and dissemination of field guides to exotic pests and diseases), the establishment and maintenance of Web sites and other forms of Internet-based communication (e.g. discussion groups and newsletters) and community-based "weed spotter" groups (e.g. the nationally coordinated Weed Alert Network and the local Victorian Weed Spotters Network). A national plant pest hotline has also been set up to encourage early reporting of serious exotic plant pests (including diseases).

Specific surveys include those undertaken by NAQS and Northwatch, a port environs survey in Queensland and Tasmania and the state forest surveillance programmes. National trapping programmes at ports of entry for Asian gypsy moth and fruit fly are other examples of specific surveys.

Asian gypsy moth trapping programme

The Asian gypsy moth (Lymantria dispar) can cause severe damage or complete defoliation of trees and has a wide host range, including eucalypts and fruit trees. It is therefore of concern to Australia not only for the economic risk it presents to forestry and horticulture but also for the environmental risk to natural habitats. The surveillance programme for this pest is coordinated by the Office of the Chief Plant Protection Officer and monitoring in the field is conducted by state and territory agencies. The most likely pathways for Asian gypsy moth are ships and shipping containers so traps are placed in a grid in and around port facilities. The surveillance network includes over 450 traps.

Fruit fly trapping programme

The national fruit fly trapping programme is a well-developed and extensive surveillance programme. It is designed as an early warning system to identify and define incursions of targeted exotic fruit fly pests (Bactrocera spp.) entering through international pathways at ports. The network includes over 1 600 traps jointly funded and managed by the Australian government and five state governments. Tasmania and South Australia carry out more extensive trapping in port cities and towns in support of area freedom programmes in those states. NAQS carries out trapping in the more remote areas and port city areas in Northern Australia.

Northern Australia Quarantine Strategy

NAQS combines border activities, scientific surveys and monitoring, and public awareness activities. Northern Australia is strategically important for all Australia in terms of quarantine because of its proximity to Southeast Asian and Pacific countries in which major pests, weeds and diseases are present.

Specific surveys by NAQS

NAQS conducts regular surveys in regions extending around the north of the entire continent, from Broome in Western Australia to Cairns in northeast Queensland. Surveys are generally confined to a coastal strip 20 km wide although other high-risk areas in the north may be included. The survey areas are classified into risk zones from very high to very low. These categories determine the survey frequency: twice a year for very high risk zones, once every five years for very low risk zones.

The highest risk zones are those parts of Australia bordering the Torres Strait, the islands of the strait and the neighbouring coastal areas of Papua New Guinea and Irian Jaya. Quarantine zones, established within and south of Torres Strait, prohibit movement of certain items from the more northern islands in the strait southwards to the Thursday Island Group, or from either of these zones southwards to the mainland. Quarantine Officers on islands of the Torres Strait and on mainland Australia undertake inspections in these zones.

Weed target list

Another NAQS initiative in managing pest incursions involves the development of target pest lists. Table 1, for example, shows the weed target list.

Table 1: Northern Australian Quarantine Strategy weed target list.






Amaranthus dubius


Brachiaria paspaloides


Austroeupatorium inulaefolium

Coix aquatica

Chromolaena odorata

Digitaria fuscescens

Mikania cordata

Digitaria insularis

Mikania micrantha

Echinochloa glabrescens


Cleome rutidosperma

Echinochloa stagnina


Fimbristylis umbellaris

Eriochloa polystachya

Schoenoplectus juncoides

Ischaemum timorense

Scirpus maritimus

Leptochloa chinensis


Equisetum ramosissimum

Leptochloa panicea


Eriocaulon truncatum

Sacciolepis interrupta


Croton hirtus


Diodia sarmentosa


Mucuna pruriens

Paederia foetida


Myriophyllum spicatum

Spermacoce assurgens


Hyptis brevipes

Spermacoce mauritiana


Limnocharis flava


Salvinia cucullata


Rotala indica

Salvinia natans


Clidemia hirta


Striga angustifolia


Rhodomyrtus tomentosa

Striga asiatica


Boerhavia erecta


Hybanthus attenuatus


Piper aduncum

The highlighted weeds (darker grey table cells) have been detected in Australia since the list was compiled in 1995.

Communication and public awareness

Working with communities is a critical part of the NAQS work programme. The residents of the islands of Torres Strait and the far north of Australia play a vital role in preventing pest incursions. They cooperate with NAQS by reporting on vessel movements and submitting for identification any specimens they believe may be a quarantine pest for Australia. To ensure cooperation continues, NAQS works with traders of the Torres Strait islands and northern Australian schools and landholders. Publications help increase public awareness of pests and pest risks.

Diagnostics and biology of pests

Diagnostics need to be correct and timely. There are three stages for diagnostic protocols:

Among new initiatives in improving the diagnosis of pests is development of a national diagnostic network. This is a project being undertaken by Plant Health Australia (PHA), an organization whose members include major agricultural industries, the Australian government and the governments of all the states and territories. Another initiative is development of diagnostic protocols for key organisms (e.g. fruit flies, lymantrids, karnal bunt, pine pitch canker).

Managing pest incursions requires an understanding of the biology and ecology of the organisms concerned. The key questions are:

Information such as host status, pest impact, control options and trade impact is necessary to answer these questions.

Australian Plant Pest Database

The Australian Plant Pest Database is an Internet-based access and search tool for plant pest and disease records residing in discrete Australian collections. Launched in April 2002, the database at the time of writing provides access to 20 pest collections and close to one million mite, nematode, insect and pathogen records. Development of this nationally coordinated database is consistent with guidelines for pest records in the international standards for phytosanitary measures, in particular ISPM 17: Pest reporting, which require documentation of sources of information to make transparent the rationale for any pest management decisions.

The records in the database include: current pest names, host plant, locality information (including map coordinates), collection reference number and collector name. The reference number allows a user to consult with the curator of a collection regarding a record and, if necessary, examine the physical specimen.

The Australian Plant Pest Database consists of three major components: the user (e.g. a plant health scientist), the central broker software and the individual plant pest databases. The user poses a query over the Internet to the broker. The broker is responsible for processing query requests and for translating data from individual databases into a consolidated result. The query received by the broker is translated and sent to the individual databases. Returned results are combined by the broker into a Web-based format of summary, detailed results and map results. These are then returned to the user.

Australia’s Virtual Herbarium

The Virtual Herbarium, an online botanical information resource accessible via the Web, is a collaborative project of the Australian, state and territory herbaria. Australian herbaria contain over six million plant specimen records that will become accessible through the AVH as they are databased. The AVH provides immediate access to these data, of particular value in displaying geographic distribution, enhanced by images, descriptive text and identification tools.

Legislative and administrative aspects

Other aspects of contingency planning for pest incursions include determination of roles and responsibilities and where legislative authority resides, and financial issues of funding and compensation.

Although the major responsibilities in management of pest risk are those of government departments and agencies (federal, states and territories), many other stakeholders are involved. Growers and primary industries, sometimes in partnerships with public-sector organizations, may be called upon. Others may be from environmental or human health groups.

Legislative authority also resides with states, territories and central government. This authority underpins the actions that may be necessary to manage pest incursions, such as survey, inspect, treat, take samples, impose quarantine measures, restrict movement or destroy material. The primary legislation relating to quarantine in Australia is the Commonwealth Quarantine Act 1908.

While this Act has provisions to give the Australian government emergency powers in the event of an epidemic, the preferred approach in the event of a pest incursion is for state and territory governments to use their legislation as the basis for establishing quarantines and related constraints on the movement of goods and people and destruction of infected or suspect material.

Where a pest incursion is considered to be of national concern, funding to manage the incursion has been based on a formula in which the Australian government pays 50 percent and states and territories pay the balance in proportion to the estimated impact within each of the jurisdictions. PHA (, a peak national body with membership from government and industry, has an important role in the development of national policy and capability to enhance the ability of Australian agriculture to respond effectively to plant pests. PHA has the primary task of developing a new cost-sharing model that includes contributions from affected industries and broadens the scope to include compensation.

The question of whether to attempt eradication of the organism or to aim for its suppression and control may be hotly debated because of the difficulties in quantifying the potential impacts and the management costs. Having agreed to proceed with collective cost-sharing, sharing the burden of funding and compensation is also complicated by the wide spectrum of possible beneficiaries of pest management actions, particularly if the benefits are not only to commercial but also to environmental and conservation interests. An important component of the PHA cost-sharing model is pest categorization, which determines the relative proportion of public and private benefit that arises from managing an incursion.

Preparedness and response planning

Among recent initiatives to increase the preparedness for pest incursions and improve response planning in Australia, the forest sector has developed a generic incursion management plan (available at The plan identifies the following stages: preparedness (e.g. collaboration between different diagnostic agencies and between relevant state agencies and private companies, access to emergency funding, pest risk assessments); detection, identification and notification; response decision; implementation; review.

The incursion response decision-making process is illustrated diagrammatically in figure 1.

Fig. 1: Incursion response decision-making process.

Pre-event processes include prevention (e.g. quarantine, monitoring and surveillance, quality management) and preparedness (e.g. incursion planning, determination of responsibilities, funding, compensation and legislation, training and awareness, research and development). The response to an incursion begins with a trigger (an initial report), preliminary assessment and diagnosis and containment of the problem. The scope of the problem is determined (e.g. disease characterization, epidemiological assessment, impact assessment). The operational response implements the predetermined response strategies. If eradication is not possible, then containment strategies are developed and implemented. At stand down, surveillance continues to ensure freedom from the pest or disease.

Such a generic plan provides a framework that can be adapted and made more detailed for specific cases where there is deemed to be a high risk of introduction or spread of a serious pest or where an incursion has already occurred. For example, specific pest response plans have been developed for papaya fruit fly, pine pitch canker, fire blight and Dutch elm disease.

Case studies of incursion preparedness and responses for specific pests

The following brief notes of Australian experience in managing specific pest incursions illustrate the size of the potential impacts of these organisms and the varying challenges and requirements for dealing with them.

Papaya fruit fly (Bactrocera papayae) response

Impact: an estimated $A100 million through increased production costs and losses, and reduced access to international markets for many horticultural products.

Pathway: smuggled fruit.

Detection: late, by a grower after the pest had established (more than one year after entry).

Surveillance: extensive lure trapping.

Diagnostics: the world authority is Australian.

Quarantine: strict controls on imported horticultural host commodities; strict internal controls on movement of product outside of the infested area.

Eradication: lure and insecticide treatments; $A35 million over four years.

Exotic fruit fly preparedness

Pre-event preparedness for fruit fly incursions includes:

The Philippines fruit fly (Bactrocera philippinensis) was detected in Darwin in November 1997. It was officially declared eradicated in May 1999 after more than 17 months with no detections. Because of early detection and effective response preparedness and planning, eradication cost $A5 million compared with the $A35 million cost for eradication of papaya fruit fly.

Red imported fire ant (Solenopsis invicta) response

Impact: potentially millions of dollars in economic impact as well as social and environmental impact if established.

Pathway: not known.

Detection: in Brisbane, February 2001, although the pest may have first arrived up to five years earlier, based on the size of the infested areas.

Surveillance: delimiting surveys in Brisbane area, continuing surveillance programme.

Diagnostics: Commonwealth Scientific and Industrial Research Organisation (CSIRO), confirmed early.

Quarantine: strict controls and extensive public awareness campaign.

Eradication: six-year, $A175 million national fire ant eradication programme.

Siam weed (Chromolaena odorata) response

Detection: first detected in Australia in Queensland by NAQS botanist in 1994.

Surveillance: ongoing surveillance revealed 780 sites within a 50-km radius of the original detection; helicopter surveillance was used because of access difficulties.

Establishment and spread: after seven years, the infestation has greatly reduced but 258 active spot sites remain partly because of a persistent seed bank and partly because of poor visibility and access to the region.

Eradication: $A1.1 million to date over seven years.

Kochia (Bassia scoparia) response

Introduction: imported in 1990 as part of seed mix for rehabilitation of salt-affected land and sown at 68 sites in Western Australia.

Establishment and spread: naturalized and actively growing at 51 sites throughout southwest Western Australia by 1992.

Risk assessment: a search of the literature quickly showed this to be a major weed.

Eradication: $A280,000 over five years. Accurate knowledge of location of infestations ensured that eradication could be achieved.

Branched broomrape (Orobanche ramosa) response

Impact: estimated at millions of dollars through potential impact on international trade and loss of productivity in horticultural industry.

Pathway: not known.

Detection: incidentally noticed because of general awareness in the region; a lack of accurate delimitation failed to reflect the true level.

Surveillance: extensive survey programme of quarantined and neighbouring properties and any properties with a link to an infested property.

Diagnostics: confirmed early.

Quarantine: containment within the 70 km × 70 km infestation.

Eradication: $A10 million to date over five years. Eradication is expected to take 15 - 20 years to complete.

Monterey pine aphid (Essigella californica) response

Impact: not a major pest elsewhere; current research indicates it may have significant impact on Pinus radiata plantations.

Pathway: uncertain, but evidence shows it could have been a "hitchhiker" on various imported material.

Detection: late, incidentally detected by an entomologist; national delimiting surveys showed it was widespread throughout Australia; existing forest surveillance programmes missed it.

Surveillance: national surveillance programme developed targeting the aphid.

Diagnostics: cooperation with United States to quickly confirm.

Quarantine: breached current quarantine, no interstate quarantine feasible or justified.

Eradication: not feasible; declared established; management programmes are being researched.

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