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Technical presentations

A global perspective on forest invasive species: the problem, causes, and consequences

Sally Campbell
PNW Research Station, USDA Forest Service, Portland, Oregon, USA

Generally defined, an invasive species is a species:

1) that is non-native to the ecosystem under consideration; and

2) whose introduction will cause or is likely to cause economic or environmental harm or harm to human health.

Invasive species are characterized by one or more of the following traits: rapid growth rate, efficient dispersal capabilities, large reproductive output, and tolerance to a broad range of environmental conditions. Introduction and establishment of invasive species is an accelerating problem worldwide due to increased trade, travel, and transport of goods. Not only is the rate of these activities greater, but also the distances covered are greater over a shorter span of time. Introductions of invasive species can occur through many different pathways, ranging from trade in non-native plants and animals, to the entry of diseased fruit brought by tourists, to the movement of insect pests via ships, planes, trains, or trucks. Introductions can be either intentional (e.g., food crops, ornamentals, pets, livestock) or unintentional.

There are environmental, economic, human health, and political consequences resulting from the introduction and/or establishment of invasive species. Environmental consequences are numerous. According to Sala et al. (2000) invasive species are among the top drivers of environmental change, globally. Some consider invasive species to be the second greatest threat to threatened and endangered species in the United States of America, following loss of habitat (Wilcove et al. 1998, CBD News 2003). Mooney (2000) reports that invasive species can disrupt natural fire cycles, deplete water supplies, and eliminate species. In 2003, the Union of Concerned Scientists stated that invasive species are one of the most serious environmental challenges we face. Economically, the cost of invasive species is measured by the amount of resource damage as well as the cost of eradication and control. Worldwide, invasive species cause an estimated loss to agricultural crops of US$55 billion annually (Bright 1999). In the United States of America alone, the estimated loss to all uses is US$137 billion per year (Pimentel et al. 2000). More extensive documentation of ecological and economic impacts is needed, especially in developing countries. Consequences of invasive species on human health range from disease epidemics, to the human health impacts of increased pesticide use, to food and water shortages. Invasive species also have political consequences. Political consequences can be measured by the impact on sustainable development when invasive species damage food and water supplies; affect human health; or prevent governments and industries from selling some types of food products, selling living commodities, or using certain types of containers and packing materials.

The problem of invasive species can be addressed by first establishing a set of goals, including:

Processes that will aid in achieving these goals include conducting invasive species risk assessments, carrying out pertinent research, monitoring ecosystems and invasive species, educating the public, collaborating with partners, developing policy and regulations, managing information, and measuring accomplishments. A number of challenges to achieving these goals exist. Scientific challenges include quickly elucidating diverse, complex aspects of a new invasive species such as its biology, epidemiology, and control approaches; the uncertainty of which species will become invasive, where they will be a problem, and when; the number of pathways and rate of spread; and the time lags between introduction and discovery, research results, treatment, policy development and implementation. Political challenges include the lack of awareness by agencies or governments; poor communication and coordination between these entities; conflicting policies between entities; gaps in policy; and the ability to fund eradication and control efforts. Lastly, ethical challenges exist where such issues as animal rights, environmental and human health risks from pesticides and biological control agents, and the use of genetically modified organisms must be considered.

Success in meeting these challenges and developing and implementing solutions for invasive species can be achieved only if we form strong collaborative partnerships within and between countries.


Bright C. 1999. Invasive Species: Pathogens of Globalization. Foreign Policy 116: 50-60.

Convention on Biological Diversity. Convention on Biological Diversity News. 2003.

Mooney H. A., and Hobbs R.J., eds. 2000. Invasive Species in a Changing World. Island Press. Washington, DC.

Pimentel D., Lach L., Zuniga R., and Morrison D. 2000. Environmental and economic costs of non-indigenous species in the United States. BioScience 50: 53-65.

Sala, O.E., Chapin F.S. III, Armesto J., Berlow E., Bloomfield J., Dirzo R., Huber-Sanwald E., Huenneke L.F., Jackson R.B., Kinzig A., Leeman R.S., Lodge D.M., Mooney H.A., Oesterheld M., Poff N.L., Sykes M.T., Walker B.H., Walker M. and Wall D.H.. 2000. Global biodiversity scenarios for the year 2100. Science 287: 1770-1774.

Union of Concerned Scientists, 2003.

Government of the United States. United States Executive Order 13112, February 3, 1999.

Wilcove D.S., Rothstein D. and Dubow J. 1998. Quantifying Threats to Imperiled Species in the United States. BioScience 48:8: 607-15.

Alien forest pests and management practices in China

Wei Diansheng
Department of Silviculture, State Forest Administration, Bejing, China

Forest pests refer to all those organisms, such as pathogenic microbes, insects, nematodes, mites, mice, rabbits and certain plants that negatively affect the growth of forest vegetation and cause economic loss. There is an abundance of pest species living in the varied forests and climatic environments in China’s widespread territory, causing severe damage to the forestry industry. With the rapid growth of trade, both domestically and internationally, the management of forest pests, especially alien pests, has become one of the most important aspects of forest management in China.

Brief introduction to forest resources in China

There are 158.9 million hectares of forests in China, covering 16.5 percent of the total territory. Among the existing forests, plantations play an important role, contributing 29.4 percent of the total, accounting for some 46.7 million hectares.

To further improve the forest resources and ecological environment, the central government initiated six major forest programmes nationwide:

Some considerable progress has been achieved. For example, 10.5 million hectares of forest have been planted; 0.17 million hectares of land have been closed for reforestation; 87 400 hectares of small drainage areas have been harnessed for erosion prevention, and 4 324 supporting water resource facilities have been constructed. More than 1 400 natural resource conservation areas have been established.

Major forest pests and damage caused in China

Statistics indicate that there are more than 8 000 forest pest species in China, of which approximately 100 have caused significant economic loss. Important native pests include pine caterpillars, poplar defoliators, poplar longhorn beetles and pine bark beetles, which infest an area of approximately 8 million hectares, annually.

Important alien forest pests in China include pine wood nematode disease, fall webworm, pine greedy scale, slash pine mealybug (Table 1). These infest an area of approximately 1.3 million hectares, annually.

The annual direct loss to the forest industry is estimated at RMB10 billion yuan (US$1.2 million). The economic losses caused by alien forest pests contribute 60 percent of the total losses, while occurring in only 20 percent of the total forest area.

Table 1: List of important alien invasive forest species in China

Common Name

Scientific name

Common Name

Scientific name

Pine wood nematode disease

Bursaphelenchus xylophilus (Steiner & Buhrer) Nickle

Fall webworm

Hyphantria cunea (Drury)

Brown spot needle blight of pine

Mycospherella dearnessii Barr

Pine greedy scale

Hemiberlesia pitysophila (Takagi)

Pine red spot

Dothistroma pini Hulbary

Pine bark scale

Matsucoccus matsumurae (Kuwana)

Olive knot disease

Pseudomonas syringae pv. savastanoi (Smith) Young, Dea & Wikie

Nipa palm hispid beetle

Octodonbta nipae (Maulik)

Poplar mosaic virus

Banana moth

Opogona sacchari (Bojer)

Mile-a-minute weed

Mikania micrantha H.B.K

Loblolly pine mealybug

Oracella acuta (Lobdell)


Eupatorium catarium Veldkamp

Coconut beetle

Brontispa longissima (Gestro)

Canadian goldenrod

Salidago Canadensis L.

Asiatic palm weevil

Rhabdoscelus lineaticollis (Heller)

Crofton weed

Eupatorium adenophorum Spreng.

Red turpentine beetle

Dendroctomus valens

Alien forest pest management practices in China

The Chinese government and its forestry agencies have made great efforts to prevent and control the spread of alien forest pests, releasing a series of regulations and management procedures. The State Forestry Administration (SFA) has established a management framework consisting of:

Two functional bodies have been established to coordinate this: the Office of Alien Forest Pest Invasion Prevention, and the Forest Pest Identification and Inspection Center.

To prevent the invasion of alien forest pests, information exchange and the sharing of experiences is being promoted between related governmental bodies, such as the State Pest Quarantine and Inspection Administration, Ministry of Agriculture, Ministry of Science and Technology, and the State Environmental Protection Administration. Overseas pest epidemic information was collected and a new book entitled "Epidemic Database of Overseas High-risk Pests" was compiled and published. The compendium contains information on more than 400 species. Quarantine nurseries and non - quarantine-object nurseries are being constructed. Pest Risk Assessment reports are required prior to the import of plant material that has not previously been imported to China or for plant material that is considered to be high-risk. The newly imported plant material must be planted in the quarantine nurseries prior to obtaining permission for import.

In order to collect timely information on alien forest pest incursions, key national inspection stations have been established in 1 000 counties nationwide, with more than 8 000 inspection locations. Most of the abnormal phenomena in forests - for example, excessive numbers of dead trees - can be observed and identified in time to arrest pest incursions. The construction of quarantine and inspection facilities around sensitive and important conservation areas, such as Huangshan Scenic Area, has been given priority.

The government has initiated several IPM programmes, state level programmes for pine wood nematode disease, red turpentine beetle and fall webworm. At a provincial level, programmes have been initiated for pine bark scale, pine greedy scale and loblolly pine mealybug.

While taking IPM measures to control important alien forest pests, the establishment of healthy forests is also being promoted. In 2001, an experimental forest health programme was initiated in five counties along the Yangtze River. By taking comprehensive measures, mixed and compound storied forests were restored or planted. With enriched biodiversity, the resistance to incursions and the recovery capacity of healthy forests was improved, thus restricting and controlling the development of pests.

Sound legislation is the basis for alien forest pest management. Besides the existing laws and regulations related to forest pest management, SFA is now drafting a new regulation entitled "Emergency controlling procedures for forest pest outbreaks", in which the control of emergent alien forest pests is an important component.

Public participation is an effective measure to prevent the occurrence and spreading of alien forest pests. The government has made great efforts to improve public awareness of the impacts of alien forest pests. The general public has learned of the damage caused, spread approaches and control measures for alien forest pests. Thus laws and regulations related to pest management are better understood and the man-made long distance transmission of forest pests has been reduced.

Challenges and suggestions

Even though a series of management measures for alien forest pests have been taken by the Chinese Government - and although considerable results have been achieved - there are still some great challenges facing the country.

All of the above-mentioned challenges need to be resolved gradually. However, this is not a task that the Chinese Government can address on its own. There is a need for inter-governmental cooperation in order to address the problems related to invasive species. The Chinese Government strongly supports the idea of establishing an "Asian-Pacific Forest Invasive Species Management Committee", and is willing to cooperate with other countries or regions in the world to prevent the invasion of forest pests.

Pest risk assessments and incursion pathways

Allan T. Bullard
Director, Forest Health Technology Enterprise Team, USDA Forest Service


Invasive species are one of the greatest global natural resource concerns. In the United States of America, invasive species cost over US$137 billion annually. Economic losses owing to non-native invasive forest pests are estimated at US$4.2 billion per year from reduced timber yields and prices, the costs of direct control of these pests and the increased costs of managing lands affected by them. Ecological impacts of non-native forest pests include: tree species conversions, wildlife habitat destruction, degradation of riparian communities, increased fuel loading, increased damage from native pests and loss of overall biodiversity. Pest risk assessments and the identification of potential incursion pathways are two useful tools that have been developed to help address the issue of invasive species.

Pest risk assessments

The purpose of pest risk assessments is to identify non-native organisms that may be introduced, in order to determine the likelihood of their introduction and establishment, and to estimate the impacts of establishment (both economic and environmental). Good pest risk assessments are comprehensive, logically sound, practical, conducive to learning and open to evaluation. In the simplest terms:

Risk = Likelihood of introduction and establishment ´ Consequences of establishment

In assessing the likelihood of introduction and establishment of an organism, factors to consider include:

To assess the consequences of an introduction and to help determine the need for and degree of action to prevent establishment, factors to consider include:

Incursion pathways

Incursion pathways are the methods by which organisms can move from source areas to new areas. Identifying these pathways and determining the most likely routes of movement for specific organisms of concern provides us with a tool to intercept potential invasions and prevent the establishment of new invasive organisms by telling us where to look for these potential pests. Pathways can be categorized into three broad areas - transportation-related, "living" industries, and miscellaneous pathways. Transportation-related pathways include all the routes related to the movement of goods and people (air, aquatic, terrestrial movement; items used in shipping such as containers and packing materials; tourism, moving and personal travel; movement of pets, etc.). "Living" industries include such areas as the movement of living organisms for food, aquaculture, pets, livestock, movement of plants and plant parts, seeds, minimally processed animal and plant products, animal and plant residues and waste. Miscellaneous pathways include other aquatic routes such as interconnected waterways, interbasin transfers and dredge spoil, as well as other unapparent routes of movement such as storms and high winds.

Working together to develop and share pest risk assessments, to identify actual and potential pathways of movement of organisms of concern, and the simple sharing of information and increased communication on the vital subject of invasive species provides us with our best chance to prevent future establishment of new invasive species and to minimize the impacts of those already present.

FAO activities related to invasive species in forestry

Simmathiri Appanah
FAO Regional Office for Asia and the Pacific, Bangkok, Thailand

The Forestry Department of FAO has initiated a number of activities with regard to biosecurity issues in the forest sector. This is part of an interdisciplinary effort to assist member countries in addressing the problems faced with invasive species in forestry. With support from the FAO-Netherlands Partnership Programme, several activities have been initiated. These include reviewing and defining the biosecurity concept in forestry, promoting collaboration with other sectors and analyzing the impacts of invasive species at the national and international levels. To support this work, several studies are being undertaken to further define certain critical issues.

Despite the global interest in biosecurity, there continues to be little clear understanding of what it means to forestry. Nevertheless, as far as forests and trees are concerned, biosecurity issues are relevant in the following five disciplines:

FAO launched a number of fact-finding studies on invasive forest-trees, including studies of the intensity of invasiveness. The global review showed that out of 1 121 exotic tree species, 443 species might be considered invasive. While biologists have mainly undertaken the work, foresters are beginning to show concern about invasive species. The terminology has often been intractable, but FAO has begun to grapple with the issue.

In one case study in South Africa, 110 invasive woody species were found in the survey area, many of which were perceived to have negative impacts. In order to raise awareness and bring balance to the issue, the study is reviewing the regulations governing plantations and land use, and is developing control campaign materials for prevention. Another case study on a specific genus, Prosopsis, which was introduced into Sahelian Africa was very revealing. The tree was introduced for soil conservation, fuelwood, desertification control, etc. While concern over its invasiveness has been expressed, the study revealed the issue is more complex. There are many circumstances where the tree has provided benefits. The study indicates that the period of introduction and local knowledge on the use of the species is critical, in weighing the costs and benefits of an invasive species. Another study was conducted on the effect of the introduction of foreign/improved germplasm, on eucalypts in Australia. The study showed that the risk of hybridization with native gene pools is very small. Nevertheless, some precautions need to be taken.

FAO has also developed simple databases on introduced, naturalized and invasive woody species. These databases are searchable, by species and by country, and include related literature and references. In addition, there is an international portal on food safety and animal and plant health. Information on international and national standards, regulations, official material relating to sanitary and other measures is also included. The information on sanitary and phytosanitary related standards is meant for consumer and environmental protection agencies, to facilitate international trade on such materials. In addition to the above, FAO is also assisting developing countries in capacity building on biosecurity issues.

Ecological and economic impacts of invasive species

Chris Baddeley
Team Leader Biosecurity Policy, New Zealand Ministry of Agriculture and Forestry

Invasive species are well recognized as having severe ecological, economic and social impacts. It is also well recognized that as a result of increasing trade and travel and the globalization of world economies that the invasive species problem is currently escalating.

Invasive species have features that enable them to establish, spread and dominate in countries that are outside their natural range. Plants and animals in the new host countries often lack defences and are therefore vulnerable to the new arrivals. Natural control mechanisms are often absent or ineffective against invasive species.

While invasive species are a major concern for all countries, open economies relying on primary production can be most severely affected. Countries with fragile economies, disturbed landscapes and a legacy of existing pest problems are also severely impacted.

Assessment of ecological impacts is likely to remain a significant challenge despite emerging resource economic methods, such as contingent valuation. It is also likely that ecological impacts will largely continue to be described in subjective terms.

Assessment of the impacts of invasive species on productive sectors and urban trees is more amenable to quantitative assessment. Economic impacts include crop production losses and the loss of access to premium markets. They also include spending on defensive measures such as:

New Zealand spends some US$175 million per year on defensive measures[1]. It also spends significant sums on incursion responses. For example, it is estimated that almost US$60 million will be spent responding to the painted apple moth.

Economic impacts of invasive species have been assessed as equivalent to some 1.4 percent of gross domestic product in the United States of America (US$137 billion per year[2]) and some 0.9 percent of gross domestic product in New Zealand[3] (US$495 million per year).

New Zealand undertakes economic impact assessments for all newly arriving invasive species where a government eradication programme is being considered. These assessments include:

Where possible, financial values for impacts are determined; otherwise impacts are described in subjective terms. These economic impact assessments are a key consideration in decisions by the government on its response to exotic pest incursions.

The International Plant Protection Convention (IPPC)

Greg Stubbings
National Manager, Forestry Section, Canadian Food Inspection Agency

The International Plant Protection Convention is a multilateral treaty for international cooperation in plant protection and is the phytosanitary standard-setting organization named in the WTO-SPS Agreement. While a number of provisions in the IPPC are shared with the WTO-SPS, the IPPC makes provisions for trade in a protection agreement and the SPS makes complementary provision for phytosanitary protection in a trade agreement.

The purpose of the IPPC is to secure common and effective action to prevent the spread and introduction of pests or harmful plants and plant products, and to promote appropriate measures for their control. The scope of the IPPC is not limited to trade. The IPPC includes both direct and indirect effects from weeds, invertebrates, diseases on agricultural plants, forests and wild flora. This includes biological control organisms. There are also provisions for research and other purposes. The original IPPC came into force in 1952, was amended in 1979, and further amended in 1997. As of April 2003, there are 120 Contracting Parties.

The key obligations of the IPPC are for the contracting party (country) to establish and administer a National Plant Protection Organization (NPPO), conduct treatments and certify exports, regulate imports and cooperate internationally with respect to sharing information on pests and regulations. Countries are expected to develop and consider phytosanitary standards. The key principles of the IPPC recognize the sovereign right for each country to regulate the entry of plants and plant products, but that measures should only be applied when necessary. Measures should be consistent with the risk, technically justified and the least restrictive, non-discriminatory and transparent (published).

An Interim Commission on Phytosanitary Measures (ICPM) has been established and is the governing body for the IPPC. This group works by consensus, and develops and adopts international standards for phytosanitary measures (ISPMs). The ICPM also promotes information exchange and technical assistance. The priority of new standards is decided by the ICPM. A working group of experts drafts the standard; the Standards Committee reviews the standard prior to country consultation. The Standards Committee reviews the country comments and when deemed ready to proceed, recommends adoption by the ICPM.

Existing International Standards

The IPPC Secretariat provides official documents (ISPMs and reports), facilitates information exchange and maintains the IPPC web site. The International Phytosanitary Portal (IPP) lists countries’ official contact points, contains official documents (ISPMs, reports) and generic phytosanitary information from countries. For more information:

International Plant Protection Convention Secretariat
Food and Agriculture Organization of the United Nations
Viale delle Terme di Caracalla
00100 Rome, ITALY
Tel: (+39) 06 5705 4812
Fax: (+39) 06 5705 6347
[email protected];

Key elements in developing a forest invasive species biosecurity strategy for Australia

Mike Cole
Office of the Chief Plant Protection Officer (OCCPO), Australian Government Department of Agriculture, Forestry and Fisheries (DAFF)

Australia is relatively free from many serious agricultural and plantation forestry pests, mainly because of its geographical isolation. This position is attributed to the fact that virtually all cultivated crops, many pasture species and a large proportion of Australia's plantation forest industries are based on exotic germplasm. Through rigorous quarantine action, and some good fortune, many serious agricultural pests have been excluded, while few indigenous pests have adapted to attack the exotic germplasm - a fact that can be attributed, in part at least, to Australia's unique flora. The impacts that new pests will have on Australian ecological and agricultural systems are, in many instances, little known. Pest risks are compounded by the wide diversity of ecological niches that Australia offers as points of incursion establishment, including both temperate and tropical environments.

The annual turnover of the Australian forest industry is valued at A$15 billion (US$10.7 billion). Protecting forests is becoming harder with the increase in global trade and travel. The risk of entry and potential establishment of exotic pests has increased the risk and threat of impact of these pests.

In addition to the natural pathway, through Northern Australia from Indonesia and Papua New Guinea, potential pest pathways to Australia include thousands of incoming air and sea freight containers and contents, 180 million mail items and over 9 million inbound passengers annually. Although numbers tend to vary from year to year, Australia must respond, annually, to approximately 40 newly recorded plant pests, 200 barrier breaches (pests that have been detected beyond the quarantine barrier but have not yet become established) and 15 000 pest interceptions at the quarantine barrier.

Preventing pest introductions is a major component in any invasive species strategy; however it is not zero-risk, with increasing pressure from both regulated trade and non-regulated trade (deliberate contravention of quarantine laws). Australia spends A$166 million (US$119 million) on quarantine activities annually and has spent over A$200 million (US$143 million) since 1996 on various plant pest eradication programmes.

On the ground response to incursions by exotic pests is only one aspect of an overall incursion management strategy. The effectiveness of a response to an incursion is heavily influenced by various factors prior to, during, and after, an exotic pest incursion. Consideration of a response to an exotic pest should not be seen as a stand-alone process, but part of an overall biosecurity and incursion management strategy.

A framework for preparing and responding to exotic pests can be seen in Figure 1. This framework includes three major stages that take into account input into the overall outcome of reducing the risk and impact of exotic pests before the pest becomes established (Pre-event), when the pest is detected (Response), and after the pest has been eradicated or managed (Recovery).

Experiences in responding to exotic pest incursions in Australia show that successful response programmes have similar characteristics indicating the suitability of some incursions to effective response and the need to handle invasive species in a total preparedness and response framework. Characteristics include:

Experience in Australia has also shown that there are key elements of invasive species preparedness and response that greatly influence the effectiveness of any response strategies. The following sections describe elements have proven to be critical in Australia and are the focus of the development of Australian invasive species strategies.

Identification of pest threats and information on biology, ecology and control

There are numerous potential exotic pests that could threaten Australian forests to various degrees. The capacity to develop and implement surveillance programmes for all potential pests is limited. Where possible, it is desirable to begin with identifying and prioritizing pest threats to help rationalize and focus surveillance resources where most appropriate. However, this must be balanced with an overall capacity to detect pests, which may have not been seen as key pests, based on overseas experience. The nature of exotic pest invasions means that pests usually arrive in Australia without natural biotic and abiotic constraints and minor pests in their native environment can become major pests in Australia.

For example, the aphid Essigella californica was first found in Australia in 1998. National surveys quickly found it in all states despite forest surveillance programmes. The aphid is not known to be a major pest on Pinus radiata elsewhere, or in its native range, but in Australia there are indications that it is causing significant damage in some states. This highlights the difficulty in identifying key target pests and being able to adequately detect them early enough for effective response.

Asian gypsy moth (Lymantria dispar) has been identified as a potential key threat, and its destructive potential has been confirmed through research on host testing with Australian native species. Although the pest has not evolved with Eucalyptus species, it readily feeds on many, highlighting its potentially significant impact on both commercial and conservation forests. Australia conducts a pheromone-trapping programme in all temperate first ports of call - one step to help mitigate this risk.

Pest status in country

A sound knowledge of the pest status of Australia's plant industries and native flora is essential if we are to avoid costly false alarms arising from findings of suspected new incursions. Occasionally, owing to a lack of surveillance or appropriate notification and recording of an exotic pest, a response is falsely triggered. There have been cases where there have been valid records indicating that a pest has been present for some time, but a new finding of the pest has resulted in the initiation of the national response system because the older records were not readily accessible. In other cases, gaps in our knowledge of plant health status has meant that it is not possible to determine, with any confidence, the status of a newly discovered organism.

Clearly, if we don't know which pests are endemic it is difficult to determine, with any confidence, the status of a newly discovered organism. This is why arthropod and pathogen collections (and disease herbaria) containing validated and well-curated specimens are critically important. These collections hold information on a pest's distribution, life cycle and host(s) and provide a basis against which to compare unknown organisms and facilitate the accurate identification of suspect exotic pests.

Figure 1: Framework for preparing and responding to exotic pests

Reference collections holding records of economically important pests are held by numerous organizations throughout Australia. The OCPPO (Office of the Chief Plant Protection Officer) and PHA (Plant Health Australia) are managing a project to improve the accessibility of these records through the development of an Australian Plant Pest Database, which links the diverse, geographically scattered databases throughout Australia so that all of the available data can be accessed from a single point via the internet. Support is also being provided for data entry and some validation of existing records.

Pest Pathways

The large number of exotic pests that pose a threat to Australia makes it difficult to take pre-emptive steps to address all of these - the resources are simply not available to do this. However, pathway analysis and risk assessment can be used to identify a "target list" of the more serious threats, keeping in mind that there still needs to be a generic capacity to respond to those pests that were not targeted and still are seen to be threats to Australia.

The following information sources may be drawn upon to determine entry pathways of exotic pests and to target potential pests: interception data collected by AQIS (Australian Quarantine Inspection Service), import statistics for host commodities and germplasm/nursery stock, quarantine import conditions, import risk analyses and market access proposals, scientific literature and databases such as the CABI Crop Protection Compendium and historical data.

Pest Impacts

A knowledge of which hosts are impacted or can act as a reservoir for establishment is essential for response decision-making. Any action to contain or eradicate a new pest needs to incorporate surveys of all host plants in the outbreak area, including those in commercial production areas, home gardens, parks and along roadsides. Various quarantine restrictions on host material to prevent intrastate and interstate spread of the pest may also be required. The speed of spread and the "invasiveness" of the pest, which includes information on dispersal characteristics, development rates and times, longevity, and vectors - among others - are important determinants of impacts.

Cost-benefit analysis is an important tool in consolidating and integrating various biological, operational and economic factors of an incursion, to allow for a more systematic analysis towards making decisions on response actions. It is a useful tool to help gauge the utility of response versus not responding, and other expenditures on non-response programmes. This analysis is done for all major incursion responses to varying degrees. However, the effectiveness of this analysis is often governed by a lack of information both biological and economic. Some components of cost-benefit analysis include:

· Direct costs - depending upon the type of pest, direct costs associated with eradication programmes may include:

· Secondary costs - for any eradication programme, there are often a number of less direct or harder to measure costs that may need to be considered, such as:

· Direct benefits - the benefits of an eradication programme represent the sum of the costs that would be incurred if the programme were not implemented. The measurement of benefits depends on the ability to predict what impact an exotic pest would have if it were not controlled. Data are also required on the value of the industry(s) at risk. In current cost-benefit analyses of eradication programmes, benefits usually include one or more of the following:

· Secondary benefits - other benefits of eradication programmes may include:

Pest control strategies

A decision on the most appropriate control strategy will depend upon where the incursion was detected (i.e. commercial/non-commercial, urban or rural setting), the extent of the outbreak, distribution of hosts, biology of the pest, specificity of chemical treatments, and environmental sensitivities. Knowledge of the types of quarantine controls that would need to be established under state legislation to contain an outbreak and options for chemical/physical control of a pest form an integral part of effective incursion management.

Quarantine and offshore activities to prevent and prepare for incursion

Quarantine controls on the entry of plants and plant products at the border, regulated by AQIS, and quarantine policy based on risk assessment, conducted by Biosecurity Australia (BA), are designed to minimize the threats to Australian from incursions of exotic pests. In addressing new market access proposals, Australia is bound by the WTO SPS Agreement, which sets conditions - based on scientific principles and risk assessment - to protect agriculture industries from exotic pests, but, at the same time, facilitate trade in agricultural commodities. Approval is subject to BA assessing that applications for entry pose an acceptable level of risk, taking account of such matters as:

Assessments made by BA in response to applications to access the Australian market are known as Import Risk Assessments (IRAs). In recent years, Australia has improved the transparency of its IRA process and encourages greater input from stakeholders.

Over the last two years, BAs forest health work programmes have included; progression of an IRA for five coniferous timber species from three countries, conducting Pest Risk Assessments (PRAs) of pine pitch canker and sudden oak death wilt, and risk assessments with regard to import of thuja logs and oversized kwila timber for construction.

BA is also currently conducting reviews on the importation of Acacia and Casuarina seed for sowing, in response to advice received from a Forest Germplasm Workshop of January 2002. It continues to progress the coniferous timber IRA consistent with international obligations, and has been involved in further work on suspended draft wood packing guidelines, in which the efficacies of proposed treatments with regard to pathogens are now subject to review.

Future forestry-related work for BA includes; a review of the species listed as being of forest and amenity significance (which require a two year post entry quarantine), progression of the coniferous timber IRA, further reviews for emergent Phytophthora species and nursery stocks, and continuing to provide advice to AQIS on timber imports and exports on an as-needed basis.

Surveillance and the ability to detect and delimit incursions

Surveillance is needed to improve our ability to detect exotic pests early. Early detection maximizes the effectiveness, lowers the costs, and increases the speed of completing eradication or suppression programmes, by being able to address a pest incursion when the population is smaller, less distributed, and not as well established. Failure to detect incursions soon after they have occurred is the major factor limiting our ability to implement effective response actions. In the overwhelming majority of cases, it is estimated that exotic pests have been present in Australia for more than a year before they are noticed and reported.

Successful containment or eradication of new pest incursions is predicated on early detection when the pest population is small, confined and not well established, although much also depends on the mobility of the pest and the proximity of the initial outbreak to host plants. While graft-transmissible pathogens and nematodes (except for those that are vectored by insects) are relatively immobile, many fungal and bacterial pathogens and arthropod pests have the capacity to spread rapidly - early detection of these is critical.

Surveillance is also needed to delimit and monitor pest incursions. The extent to which a pest population is distributed must be known to properly respond to and manage pest incursions. Ongoing pest monitoring gauges the effectiveness of eradication or suppression actions.

There are two major types of surveillance (as defined in the International Standards for Phytosanitary Measures, Guidelines for Surveillance) - specific surveys and general surveillance. Both specific surveys and general surveillance, which includes awareness programmes, are useful in various forms to be able to detect pest incursions at an early stage and increase the effectiveness of response programmes, while mitigating impacts while pests still have a limited distribution.

Specific surveys

Specific surveys include early warning programmes to detect exotic pests, and delimiting surveys to define and monitor exotic or endemic pest populations. These surveys usually require more resources and incur relatively higher costs. Specific surveys are dependent on the following factors: targeted pest(s), scope of survey based on the biology, ecology, likely pathways of entry of the pest (to indicate geographic area), sample units, timing, and methodologies including:

To maximize survey effectiveness and increase the likelihood of detecting pests, surveys should take into account the reported distribution of the pest, pest biology/ecology and climatic range and the distribution of potential host plants.

Specific surveys are based on target pests and utilize sample-survey methodologies. Regrettably, there are other factors that influence this approach and undermine its potential for success, such as availability of appropriate technologies acceptable to trading partners and domestic users, local expertise, experience in identification, and access to national and international databases for verification.

Trace-backs are also important to try to identify the source of an outbreak and to fully delimit an incursion. Tracing is an investigative process that requires the cooperation of the owners of affected premises to determine where the pest may have come from and whether it may have been spread to other properties. The movement of plants and plant products (including nursery stock/seeds), equipment, vehicles and people to and from the affected premises must be thoroughly investigated.

Surveillance activities offshore and at the border are also part of the overall surveillance network to provide surveillance information to predict potential problems or detect pests before they have had a chance to arrive at or pass through the quarantine barrier. Both can give a profile of potential problems that may require further surveillance action.

Surveillance activities at the quarantine barrier offer a primary line of defence against exotic pest incursions, as well as giving a profile of the pests that Australia is being exposed to - for further consideration in response planning. These activities include:

General surveillance

General surveillance is the process whereby pest information is gathered through a variety of sources other than specific surveys. General surveillance is dependent on an effective education and awareness programme to allow stakeholders to readily recognize the pest or appropriate pest symptoms and a communication and reporting system to allow potential detections to be reported and appropriate action to be taken.

This type of surveillance is relatively low cost and does not require specific technology. It is the act of detecting a disease, pest or a weed based on knowledge of a local area or recognizing symptoms previously encountered in publicity or awareness material. To increase the effectiveness of this type of surveillance, a wide range of stakeholders should be included. These are characterized by the use of a range of stakeholders and awareness programmes that enable the detection of pests during the course of normal activities. In Australia, most plant health surveillance is general surveillance due to the costs and limited methodologies for specific surveys. Improving the awareness of growers, agribusiness, and others involved in the plant industries, can harness many eyes to be on the look out for the new and the unusual.

Training on how and when to monitor for pests, on procedures for sampling suspect material, and notifying the relevant authorities, is an integral component of any general surveillance strategy. There are a number of approaches that can be taken by industry and government agencies to raise industry/community awareness of exotic plant pests. These include the production of "ute" guides, fact sheets or illustrated brochures on pests of concern, placing articles in industry magazines, newspapers and other popular publications, local radio and television coverage, training on the recognition of exotic pests and symptoms, and displays/exhibits at agricultural and community shows - among other things. Important information to include in general awareness programmes includes: significance of the pest, host range, distribution, pathways, favourable conditions for symptom development, potential impact on industry, symptoms to watch out for, importance of reporting an outbreak or suspect material, and who to contact. An exotic forest pest booklet has been prepared and distributed to over 5 000 forest health stakeholders in Australia to enhance capacity to detect and report major exotic pests.

A clear notification procedure is essential to capture general surveillance information. A national pest hotline has been developed to be used during national surveillance and response campaigns. There is also a project through OCPPO to develop a national exotic pest notification system and a specific industry-based exotic pest surveillance network, to capture ongoing surveillance activities being carried out by a variety of plant health stakeholders.

The present system for detecting exotic pest incursions in Australia is based on a combination of specific monitoring activities, general surveys across northern Australia, state government and industry awareness programmes, and ad-hoc reporting (by growers, members of the public, etc).

The success of incursion management relies heavily on grower participation in passive or general surveillance to increase the chance of early detection of exotic pests. Currently, the OCPPO and Plant Health Australia (PHA), have developed a national plant pest hotline telephone reporting system, with associated targeted publicity awareness material, to more effectively capture potential detection information through general surveillance activities. The Department of Agriculture Forestry and Fisheries (DAFF) has produced a field guide to exotic pests of forest and amenity trees and timber to encourage early reporting of suspect outbreaks of these pests.

States have the major role surveying forest health. Annual surveys of plantations and routine general surveillance of commercial forests are conducted by state forest agencies. The surveys in native forests target key areas and perceived high-risk zones.

The Commonwealth, through state government agencies, runs a national trapping programme for Asian gypsy moth. The national Asian gypsy moth trapping programme serves as an early warning system to detect incursions of exotic Lymantrid species entering through Australian ports. It is funded by DAFF and coordinated by the OCPPO. Ships and shipping containers are seen as likely pathways for entry, so the trapping programme is centred in the first ports-of-call. The programme is based on a network of Delta traps on a 1-kilometre grid out to 2 kilometres from port facilities, and a 2-kilometre grid from the boundary of the 2-kilometre zone out to 5 kilometres from the port facility centre. Actual trap numbers per port facility vary, with a maximum of 40 traps per port. The surveillance network includes over 450 traps. Field monitoring/servicing of traps is carried out by state agriculture or forestry agencies.

The Northern Australia Quarantine Strategy (NAQS) is a programme of AQIS that is responsible for monitoring and surveillance to provide advanced or early warning of exotic pest threats. The purpose of the programme is to limit the opportunity for exotic pests to establish and remain undetected in remote areas. Surveillance targets are based on pest risk analyses that identified northern Australia as a pathway for entry of exotic pests of major plant host groups.

Exposure of NAQS scientists to exotic pests in the region builds expertise and increases confidence that exotic pests will be detected in regular surveys across northern Australia. The onshore component of the NAQS monitoring and surveillance programme covers a coastal band, 20 kilometres in width, across northern Australia, from Broome in the west to Cairns in the east. NAQS activities also extend offshore to East Timor, Papua New Guinea and Indonesia. The initiative includes trapping for exotic fruit flies on the islands of the Torres Strait, as well as a public awareness programme known as Top Watch.

Pest diagnostic capacity

Early detection of suspect exotic pest incursions, followed by rapid and accurate diagnosis, is essential if opportunities for eradication are to remain viable. The development and maintenance of appropriate diagnostic procedures to accurately diagnose plant pests - and in particular, exotic plant pests - are essential components of any pest preparedness and response activities. It is obvious that the correct and timely identification of exotic pests is essential in not only triggering response actions, but also in confirming negative results. A decision on whether to eradicate, contain or manage an outbreak of an exotic pest must be made quickly and depends on an ability to obtain a rapid and accurate diagnosis of the organism involved.

There are a number of factors that constitute good diagnostic capacity. These include: taxonomic or diagnostic expertise to identify target organisms, both in the laboratory and field, access to validated reference specimens and associated records, dedicated laboratory facilities with the necessary equipment, chemicals, etc, required for specialist diagnostic tests. In the event of a serious incursion, these facilities must be able to handle a high volume of samples and, if necessary, be registered as quarantine areas by AQIS - subject to controls on the movement of personnel, plant material and equipment, nationally-agreed protocols and minimum standards for diagnostic testing. Systems should exist for auditing to ensure reliability of tests and national coordination to avoid unnecessary duplication of services and to make the most of a declining pool of resources for diagnostic work.

In 1998, a Bursaphelenchus sp. nematode was detected on various pine species in Melbourne. Local government workers initially reported the dying pines. As a precaution, a national response was developed that included a survey and eradication of infected pines in Melbourne. Infected pines showed a syndrome of sudden decline and death, but the syndrome was not consistent and was compounded by other disease and abiotic factors such as salt levels. Pathogenicity testing and diagnostics have proven difficult and no confirmation of the species, or illustration of it being a pest, has been made to date. During the national surveys many previously undescribed nematodes were found (not causing primary disease). This case highlights the lack of understanding of current plant health status, roles of exotics in a new ecosystem and lack of plant health capacity to diagnose potential plant pests, especially those that may not be of major pest status elsewhere.

Diagnostic services in Australia are provided via a combination of government laboratories (state agencies and CSIRO), commercial laboratories, universities, and pest and disease specialists who perform diagnostic duties as part of their job. A recent assessment of the current status of diagnostic capacity in Australia found that:

The OCPPO and PHA have recognized the importance of strengthening diagnostic capacity and are committing resources to the development of national diagnostic standards for priority exotic plant pests as well as a diagnostic network to identify and network domestic and international diagnostic expertise to be used in pest identifications.

For forestry, diagnostic protocols being developed include: pine pitch canker (Fusarium circinatum), Eucalyptus rust (Puccinia psidii) and Bursaphelenchus spp. Key elements of protocols and a national network include:

Stage 1: Initial detection

· Diagnostic information:

· Notification/reporting:

Stage 2: Intermediate diagnosis - "alters" to confirm tentative diagnosis

· Protocol for handling material, including:

· Diagnostic information:

· Reporting:

Stage 3: Specialist diagnosis - agreed reference laboratory verifies diagnosis

· Diagnostic information:

· Reporting

Communication roles and responsibilities

A clear understanding of incursion management procedures needs to be effectively communicated to a wide range of plant health stakeholders. These should encompass several areas, such as, initial detection and reporting, through to compliance with quarantine and control activities. A lack of a strategy for ensuring that there are functional lines of communication between government agencies, industry bodies and other stakeholders can impede the effectiveness and acceptance of incursion responses. Communication strategies need to identify the key industry players to be contacted in the event of an exotic pest outbreak, and to ensure that industry is aware of appropriate procedures for liaising with incursion activities including media, especially during the early stages of an incursion. Effective systems for management and coordination at the Commonwealth, state and industry level are essential for the success of incursion response programmes.

Current biosecurity planning in coordination with governments and industry is developing industry specific communication and management strategies to effectively identify agreed government, industry and public involvement.

Legislative authority to respond to an exotic incursion

Recommendations made by the Consultative Committee (CC) for response actions are carried out under state legislation, which for Queensland is the Plant Protection Act 1989, for Victoria is the Plant Health and Plant Products Act 1995, and so on (the relevant acts are listed in Table 2). These acts enable government agencies to:

In the event of a new incursion, it is primarily the state plant protection legislation listed in Table 2 that will be utilized to respond. The Commonwealth Quarantine Act 1908 operates alongside relevant state acts and has broad coverage over matters of quarantine concern in Australia. However, in cases where a state law is inconsistent with a Commonwealth law, the Commonwealth law prevails and the state law is invalid. Areas where legislation could impact on effective response to an exotic incursion include:

Funding and compensation

Currently, incursion funding requires negotiation with the relevant Finance Department in the state/territory and Commonwealth, on the occasion of each incursion. There are no funds in reserve to mount immediate action, such as delimiting surveys, where an outbreak is suspected or confirmed. In practice the affected state(s), in view of the emergency, proceeds with containment operations before funding is settled on the expectation of reimbursement on a customary 50:50 cost-sharing basis. A further complication is that emergency actions by an affected state must frequently be taken before the nature of the containment actions is endorsed through the Consultative Committee process, in expectation that the state's actions will be ratified retrospectively.

The Plant Health Committee (PHC) considered the matter of standardization of costing for eradication campaigns in 1998 (PHC 18). It recommended to the Standing Committee for Agriculture and Resource Management that cost-sharing arrangements should cover the full costs of diagnostic services (including on-costs) and the direct costs of other response actions, such as salaries for existing and additional staff, with the states covering basic infrastructure costs (i.e. on-costs/overheads). In addition, the PHC agreed that cost-sharing arrangements should only be applied to targeted surveys to delineate the extent of an outbreak, concentrating primarily on the edges of the known outbreak site, and to restore pest-free-area status in the outbreak area.

The general principles governing Commonwealth/state cost-sharing arrangements for response actions are now reasonably clear-cut and there is usually agreement between the states and Commonwealth on what is and isn't covered under these arrangements. However, the specific details of cost-sharing can be less clear, especially in cases where there is debate on whether the programme is an eradication campaign or a suppression programme. Approval of funding by the Primary Industry Standing Committee (PISC) is not guaranteed and considerable negotiation on the part of officers in both state and Commonwealth departments can be required to secure funding. PISC agriculture agencies and individual agricultural industries are currently developing and negotiating cost sharing models between governments and industries. The core principle being applied is that the level of contribution by government or industry would be based on the pest's level of impact and benefits of control/eradication to an industry versus the public.

Defined endpoint and monitoring

The outbreak of an exotic pest may result in an immediate loss of access to interstate and international markets, until certain conditions can be met or eradication is declared. For exporting industries in particular, the costs associated with restrictions on host produce can be significant.

While there are IPPC guidelines on eradication and developing area freedoms, these guidelines are generic. Before initiating a response programme, clear goals and milestones should be set; based on biological and operational factors, ongoing monitoring and review of the programme, and the likelihood of success. Factors such as increased distribution, ineffective controls, and persistence - among others - can trigger the legitimate closure of a programme and/or direct it into developing area freedoms, or ongoing management. If the pest outbreak is restricted to only a part of the country it is possible to use surveys to establish areas that are unaffected by the disease. "Pest Free Areas" (area freedom) can be used to underpin access to local and overseas markets for various plant products provided that these are established, maintained, and verified as being pest free in a manner consistent with the IPPC standard.

An increased level of preparedness and response planning

In 2000, the national Forest Health Committee released a Generic Forest Incursion Management Plan (GIMP) to facilitate preparedness and response actions to potential new incursions of exotic pathogens or invertebrate pests into Australia.

Currently, Plant Health Australia, in association with various members, is developing specific industry biosecurity plans, which - at this time - do not include forest industries, but may serve as a model for future development of emergency response planning. Key elements to developing appropriate response plans include:

It is impractical to develop pest-specific planning for all the numerous potential plant pests and, therefore, a generic system is required that can offer procedures to facilitate rapid development of pest-specific responses based on incursions. In Australia, there is a generic incursion management plan that offers a structured approach to assess and respond to incursions through the Plant Health Committee, Forest Health Committee and/or Australian Weeds Consultative Committee, which are composed of technical and policy staff from relevant government agencies. In Australia, the majority of exotic pest responses are managed under generic incursion management due to the number and scope of pest incursions and potential pest incursions. In most instances, appropriate and timely diagnostics, quarantine, management, communication and funding decisions have been made.

Specific pest response plans can be developed for targeted key pests and those that have very high potential impacts. In pest-specific plans, information on biology and ecology - such as host ranges, agreed diagnostic procedures, quarantine procedures, management procedures, communication and funding - is developed prior to an incursion and can aid in a rapid response and a clear understanding of roles and responsibilities. While pest-specific plans can assist in the decision and response process they are not static and require constant updating. There is currently a major initiative to involve governments and industry in developing biosecurity strategies for key specific pests, to enable more defined funding arrangements and a better level of preparedness.

Factors whose development prior to an incursion aid in effective responses include:

· Prevention:

· Preparedness:

· Response planning:

[1] Ministry of Agriculture and Forestry internal paper on biosecurity funding.
[2] Pimental, D., et al 1999. "Environmental and Economic Costs Associated with Non-Indigenous Species in the United States."
[3] Hackwell, K., and Bertram, G., 1999, "Pests and Weeds - A blueprint for action," compiled for the New Zealand Conservation Authority.

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