Review of policy: Alternative risk management measures to import




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Pest risk analysis


Plant Biosecurity has conducted this pest risk analysis (PRA) in accordance with the International Standards for Phytosanitary Measures (ISPMs), including ISPM 2: Framework for pest risk analysis (FAO 2007) and ISPM 11: Pest risk analysis for quarantine pests, including analysis of environmental risks and living modified organisms (FAO 2004). The standards provide a broad rationale for the analysis of the scientific evidence to be taken into consideration when identifying and assessing the risk posed by quarantine pests.

Following ISPM 11, this pest risk analysis process comprises of three discrete stages:



  • Stage 1: Initiation of the PRA

  • Stage 2: Pest Risk Assessment

  • Stage 3: Pest Risk Management

Phytosanitary terms used in this PRA are defined in ISPM 5 (FAO 2012).

1.9Stage 1: Initiation of the PRA


The initiation of a risk analysis involves identifying the reason for the PRA and the identification of the pest(s) and pathway(s) that should be considered for risk analysis in relation to the identified PRA area.

This commodity-based pest risk assessment was initiated by Plant Biosecurity as a basis for a review of the existing phytosanitary regulations to import Lilium spp. cut flowers material into Australia.

In the context of this PRA, Lilium spp. cut flowers are a potential import ‘pathway’ by which a pest can enter Australia.

The pests associated with Lilium spp. cut flowers from Taiwan were tabulated from published scientific literature, such as reference books, journals and database searches. This information is set out in Appendix A and forms the basis of the pest categorisation.

For this PRA, the ‘PRA area’ is defined as Australia for pests that are absent from Australia or of limited distribution and under official control in Australia.

1.10Stage 2: Pest Risk Assessment


A pest risk assessment is the ‘evaluation of the probability of the introduction and spread of a pest and of the magnitude of the associated potential economic consequences’ (FAO 2012). The pest risk assessment provides technical justification for identifying quarantine pests and for establishing phytosanitary import requirements.

This is a commodity-initiated pest risk analysis and risk is estimated through a standard set of factors that contribute to introduction, establishment, spread or economic impact potential of pests. This pest risk assessment was conducted using three consecutive steps: pest categorisation; assessment of the probability of entry, establishment and spread; and assessment of potential consequences.


1.10.1Pest categorisation


Pest categorisation is a process to examine, for each pest identified in Stage 1 (Initiation of the PRA process), whether the criteria for a quarantine pest is satisfied. In the context of cut flowers, pest categorisation includes all the main elements of a full pest risk assessment but is done in less detail and is essentially a quick assessment to identify pests of quarantine concern. The process of pest categorisation is summarised by ISPM 11 (FAO 2004) as a screening procedure based on the following criteria:

  • identity of the pest;

  • presence or absence in the endangered area;

  • regulatory status;

  • potential for establishment and spread in the PRA area; and

  • potential for economic consequences (including environmental consequences) in the PRA area.

Pests are categorised according to their association with the pathway, their presence or absence or regulatory status, their potential to establish or spread, and their potential for economic consequences. Pests associated with Lilium spp. cut flowers listed in Appendix A were used to develop a pathway-specific pest list for Lilium spp. cut flowers from Taiwan. This list identifies the pathway association of pests recorded on Lilium spp. cut flowers and their status in Australia, their potential to establish or spread, and their potential for economic consequences. Pests likely to be associated with cut flowers, and are absent or under official control in Australia, may be capable of establishment or spread within Australia if suitable ecological and climatic conditions exist.

1.10.2Quarantine pests associated with Lilium spp. from Taiwan


Quarantine pests associated Lilium spp. cut flowers from Taiwan are identified in Appendix A. The quarantine pests of Lilium spp. from all sources identified in the pest categorisation are listed in Table 3. These pathogens fulfil the International Plant Protection Convention (IPPC) criteria for a quarantine pest. Specifically:

  • these pests are economically important (as they cause a variety of direct and indirect economic impacts, such as reduced yield, reduced commodity value, loss of foreign or domestic markets); and

  • these pests are not present in Australia or have a limited distribution and are under official control.

Association with the host commodity provides the opportunity for pathogens and pests to enter Australia. Arthropod pests have a direct pathway on cut flowers. Viral pathogens may be transmissible in the presence of arthropod pests that act as vectors. However, cut flowers have a lower pest risk than nursery stock and material for planting given the chance of establishing a disease in a new environment is significantly enhanced if the diseases can develop within a living plant, and this plant is grown in the proximity of other hosts. The Lilium spp. cut flower species assessed are not propagable.

Table 3 Quarantine pests for Lilium spp. cut flowers from Taiwan

Pest

Common name

      ARTHROPODS

COLEOPTERA (beetles, weevils)




Harmonia axyridis (Pallas) [Coccinellidae]

Lilioceris formosana Heinze [Chrysomelidae]

Lilioceris merdigera (Linnaeus) [Chrysomelidae]

Sangariola punctatostriata (Motschulsky) [Chrysomelidae]

Harlequin ladybird

Leaf beetle

Leaf beetle

Lily leaf flea beetle



DIPTERA (flies, gnats, midges)




Liriomyza huidobrensis (Blanchard) [Agromyzidae]

Liriomyza trifolii (Burgess) [Agromyzidae]

Chromatomyia horticola Goureau [Agromyzidae]

Leafminer

Leafminer

Leafminer


HEMIPTERA (aphids, leafhoppers, mealybugs, psyllids, scales, true bugs, whiteflies)

Pseudococcus comstocki (Kuwana) [Pseudococcidae]

Comstock's mealybug

LEPIDOPTERA (moths, butterflies)




Agrotis segetum Denis & Schiffermüller [Noctuidae]

Euproctis taiwana (Shiraki) [Lymantriidae]

Kaniska canace Linnaeus [Nymphalidae]

Orgyia postica Walker [Lymantidae]

Xylena formosa (Butler) [Noctuidae]

Cutworm, dark moth

Tussock moth

Blue admiral

Tussock moth

Cutworm


THYSANOPTERA (thrips)




Haplothrips chinensis Priesner [Phlaeothripidae]

Frankliniella intonsa (Trybom) [Thripidae]

Megalurothrips distalis (Karny) [Thripidae]

Chinese thrips

Flower thrips

Bean blossom thrips


VIRUSES




Lily mottle virus LMoV [Potyviridae: Potyvirus]

Lily virus X LVX [Flexiviridae : Potexvirus] (synonym Lily X potexvirus)

Plantago asiatica mosaic virus PlAMV [Alphaflexiviridae : Potexvirus]

Strawberry latent ringspot virus SLRSV [Secoviridae : Genus Unassigned] Tobacco ringspot nepovirus TRSV [Secoviridae : Nepovirus]





1.10.3Entry, establishment and spread


Details of how to assess the ‘probability of entry’, ‘probability of establishment’ and ‘probability of spread’ of a pest are given in ISPM 11 (FAO 2004).

Probability of entry


The probability of entry describes the probability that a quarantine pest will enter Australia as a result of trade in a given commodity, be distributed in a viable state in the PRA area and subsequently be transferred to a host.

  • Lilium spp. flowers are assumed to come from areas where the above pests occur and are, therefore, likely to enter on imported lily cut flowers.

  • The pests’ ability to survive on host cut flowers which are maintained in healthy condition during transport acts to assist their viability en route to, and during distribution across, Australia.

  • Viruses, as a rule, systemically infect all parts of host plants. Therefore, cut flowers provide a pathway for viruses.

  • The bulk of Taiwan’s imports of certified bulbs for planting are from the Netherlands. Planting stock is of high health status and certified for freedom from viruses of quarantine concern for Taiwan by the Netherlands. Therefore, the probability of infected mother plants in Taiwan will be reduced and the entry of infected cut flowers into Australia through cut flower importations will be similarly reduced.

  • Due to their short shelf life, Lilium spp. cut flowers will be transported in cool conditions, which are unlikely to adversely affect survival of arthropod pests and viruses.

  • Cut flowers may contain arthropod pests which may be hidden in stem sheaths or closed flowers. These pests may not be detected by inspection.

  • Due to the nature of packaging arthropod pests are likely to remain associated with the commodity.

  • Upon arrival in Australia, arthropod pests may readily be distributed to susceptible hosts. Identified pest such as thrips and coleopterans are quite mobile with wide host ranges and are likely to readily find a suitable host species. Lilium spp. cut flowers are likely to be widely distributed through florists and other points of sale. Due to the short shelf life of lily cut flowers, their distribution is likely to occur soon after importation, which will assist the probability of arthropods being distributed in a viable state.

Probability of establishment


Establishment is defined as the ‘perpetuation for the foreseeable future, of a pest within an area after entry’ (FAO 2012).

  • The categorisation process has not highlighted any fungal or stramenopile pests that are associated with Lilium spp. cut flower imports from Taiwan. The pests of concern are viruses and arthropods.

  • Due to the systemic nature of viruses, propagative material is a major pathway for dispersal. However, the scope of Lilium spp. cut flowers from Taiwan is limited to varieties which are free of bulbils. These varieties are non-propagable. Therefore, systemic viruses are highly unlikely to establish.

  • Lilium spp. cut flowers are likely to be disposed of in backyard compost heaps or as green waste in backyards, roadsides and other public locations, as well as in municipal waste disposal. The disposal of lily cut flowers in municipal waste is likely to reduce the probability of establishment of arthropod pests. However, disposal in other locations will provide the opportunity for establishment.

  • Once arthropod pests have been distributed to a susceptible host, the likelihood of establishment is considered high.

Probability of spread


Spread is defined as ‘the expansion of the geographical distribution of a pest within an area’ (FAO 2012). The probability of spread considers the factors relevant to the movement of the pest, after establishment on a host plant or plants, to other susceptible host plants of the same or different species in other areas.

  • The ability of arthropod pests to be introduced and distributed throughout Australia on cut flowers through human mediated spread (distribution to florists and other points of sale) is a high risk for continued spread post-border in Australia. Pest related factors which would aid the spread of the pest once it has established in Australia (such as wind or mechanical transmission) will increase the pest’s ability to spread.

  • The systemic nature of some of the pests associated with propagative material (i.e. viruses) is a major pathway for dispersal. However, the scope of Lilium spp. cut flowers from Taiwan is limited to varieties which are free of bulbils. These varieties are non-propagable. Therefore, systemic pests are unlikely to establish and spread via propagation.

3.2.4 Consequences


The purpose of assessment of potential consequences in the pest risk assessment process is to identify and quantify, as much as possible, the potential impacts that could be expected to result from a pest’s introduction and spread.

The basic requirements for the assessment of consequences are described in the SPS Agreement, in particular Article 5.3 and Annex A. Further detail on assessing consequences is given in the ‘potential economic consequences’ section of ISPM 11. This ISPM separates the consequences into ‘direct’ and ‘indirect’ and provides examples of factors to consider within each.

The introduction of pests which meet the criteria of a quarantine pest will have unacceptable economic consequences in Australia as these pests will cause a variety of direct and indirect economic impacts. The identified pests are of economic concern and do not occur in Australia. A summary and justification is provided below:


  • Direct impacts of the introduction and spread of multi-host pests in Australia will not only affect the imported host but also other hosts. Introduction and establishment of quarantine pests in Australia would not only result in phytosanitary regulations imposed by foreign or domestic trading partners, but also in increased costs of production including control costs.

  • Quarantine pest introduction and establishment would also be likely to result in industry adjustment. The potential economic impact for cut flowers is high. Without controls these pests have the potential to spread further in the trade network and could potentially expand their host range.

  • Arthropod pests such as flower thrips can cause damage to ornamental flower buds, and to flowers of many leguminous plants or fruit crops which will not only require control if they establish and spread. They will affect cut flower trade as phytosanitary restrictions can apply.

  • Most viruses of quarantine concern on lilies affect ornamentals and can cause deformation, asymmetrical opening of flowers, or necrosis and discolouration leading to decreased flower value and potential loss of markets locally and internationally. Others such as Tobacco ringspot nepovirus and Strawberry latent ringspot virus have a wide host range and can affect different crop species and ornamentals.

  • Viruses are considered important as they cause a variety of direct and indirect economic impacts, such as reduced yield, reduced commodity value and loss of foreign or domestic markets. Therefore, these pests have a potential for economic consequences in the PRA area. Cut flowers do not present a direct pathway for viruses, which need to be vectored into suitable hosts. However, the presence of these pathogens in Australia would impact upon Australia’s ability to access overseas markets.

3.2.5 Unrestricted risk estimate


As a result of these pathway specific factors, the overall likelihood for the probability of entry, establishment and spread is considered to be above the ALOP for arthropod quarantine pests entering on Lilium spp. cut flowers in the absence of management measures.

Arthropods and viruses listed in Table 3 are of economic significance and are either absent from Australia, or if present, are under official control. Therefore, arthropod pests of Lilium spp. cut flowers meet the IPPC criteria for a quarantine pest and phytosanitary measures are justified to manage these pests.


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