Questions and answers: Final pest risk analysis report for Drosophila suzukii

24 April 2013​​​​
Pest risk analysis (PRA)

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Why has this PRA being undertaken?

The Department of Agriculture, Fisheries and Forestry helps people and goods move in and out of Australia while keeping Australia safe and protecting our industries from pests and diseases that exist in many other parts of the world.

As part of this role, Australia has responded to the incursion of a new pest, spotted-wing drosophila (Drosophila suzukii), in North America where it was confirmed attacking a range of fresh fruits in 2009. Later, it was confirmed present in Europe where it was also attacking a range of fresh fruits.

Australia imports several host fruit from the USA – cherries, strawberries and table grapes that could allow this pest to enter and establish in Australia.

The department announced the commencement of a PRA on 31 March 2010. The release of the final PRA report completes the current risk assessment process.

What did Australia do about Drosophila suzukii while the PRA was being finalised?

In response to the risks associated with the import of host fruits that Drosophila suzukii can attack, Australia introduced emergency quarantine measures on cherries, stone fruit, strawberries and table grapes. Emergency measures were applied before trade in host commodities could re-commence for the 2010 season. Those measures applied to current imports and those that are imminent because of an import risk assessment or policy review.

Why didn’t Australia ban imports until the PRA was completed?

Under the WTO SPS Agreement , Australia is obliged to consider emergency measures that manage the risk of a pest entering and establishing in Australia and are least trade restrictive.

What are emergency measures?

Emergency measures are immediate actions taken in response to a new or unexpected quarantine risk.

Once emergency measures are applied, under the SPS Agreement, Australia has an obligation to conduct a PRA to assess the long-term risk and ensure that continuing the measures is technically justified.

What were the emergency measures and why are they considered effective?

Strawberries and cherries from the USA already have methyl bromide fumigation as a treatment to manage other quarantine pests – methyl bromide fumigation is internationally recognised as effective in killing insects.

Before Australia accepted this treatment as effective against Drosophila suzukii, we required information from the USA confirming its efficacy. Australia received efficacy information for all fruits, showing 100% mortality of thousands of Drosophila suzukii, before trade re-commenced.

Since the information provided was still considered preliminary, Australia required an additional inspection to verify the treatment was effective. The USA authorities were required to perform a 600 unit fruit inspection, where fruit is either cut to detect internal life stages (strawberry) or inspected under optical magnification (x20; cherries & table grapes) to identify infested fruit. The detection of live Drosophila suzukii results in the rejection of the treatment lot.
To verify that the emergency measures had been completed, the department performed another 600 unit inspection.

Are the emergency measures still active?

The emergency measures were in place for two years. This provided time for the US to develop measures that were more permanent. Australia accepted methyl bromide fumigation as a suitable standalone treatment for strawberries for the 2011 export season and for cherries for the 2012 export season.  Australia accepted a combination treatment of sulfur dioxide/carbon dioxide fumigation followed by cold treatment for table grapes for the 2012 export season. Treatments were accepted based on submissions from the US supporting the efficacy of a proposed treatment.

Stakeholders were notified of these changes by a quarantine alert.

The US also provided treatment efficacy information for methyl bromide fumigation for peaches and nectarines and the final PRA report recommends this treatment as suitable to manage Drosophila suzukii.

What is a PRA and how does it work?

A pest risk analysis (PRA) is a process that identifies and assesses risks posed by a pest or disease relevant to imports. If those risks exceed Australia’s appropriate level of protection, the PRA specifies what measures should be taken to reduce those risks to an acceptable level. A PRA is conducted to the same scientific standard as an Import Risk Analysis (IRA) as described in the Import Risk Analysis Handbook 2011, available on the department's website.
Like an IRA, this PRA was issued as a draft report for consultation.

Where there any submissions received on the draft PRA for Drosophila suzukii?

The department issued a draft PRA report for Drosophila suzukii on 21 October 2010 for stakeholder comment.

Eight submissions were received, seven domestic and one from an international stakeholder. The comments were considered and where relevant, included in the final PRA report.

What pathways were identified in the final PRA report?

The final PRA report identified fresh fruit as a pathway that presents a risk above Australia’s appropriate level of protection. Hosts identified include;

  • caneberries, cherries, stone fruit, strawberries, blueberries, grapes, mulberries, figs, hardy kiwis, gooseberries and currants.

What quarantine measures have been recommended for Drosophila suzukii?

The recommended quarantine measures are a combination of risk management measures and operational systems that will reduce the risk associated with the importation of host commodities into Australia to achieve Australia’s appropriate level of protection (ALOP), specifically:

  • area freedom; or 
  • a systems approach; or 
  • application of a treatment effective against the most tolerant life stages of Drosophila suzukii. Approved treatments include methyl bromide fumigation for strawberry, cherry and stone fruit (peach and nectarine only), or
  • sulphur dioxide/carbon dioxide fumigation followed by a six day cold treatment for table grapes;
  • a supporting operational system to maintain and verify the phytosanitary status of consignments. The department will verify that the proposed phytosanitary measures have occurred.

Will Australia be adequately protected from Drosophila suzukii?

A comprehensive risk assessment of import pathways has been undertaken and, where appropriate, risk management options are recommended to manage the risks associated with commodities that could allow Drosophila suzukii to enter and establish in Australia. The final PRA report is based on the latest available scientific information and the measures proposed reflect Australia’s overall approach to managing quarantine risks.

Are there any regional differences for Australian states?

No. Drosophila suzukii is absent from all of Australia. The initial emergency measures and the recommendations of the final PRA report apply to all of Australia.

Does Australia allow any imports of host fruit?

Australia currently only imports host fruit from the USA – strawberry, cherries and table grapes.

Australia has completed an IRA for stone fruit (apricots, nectarines, peaches and plums) from the USA on 19 July 2010 and the final PRA report outcomes will apply to this commodity. The US provided efficacy data on methyl bromide fumigation for peaches and nectarines. The final PRA report recommends that stone fruit (peach and nectarine only) be fumigated with methyl bromide. The acceptance of a treatment for stone fruit to manage Drosophila suzukii completes the IRA process for US stone fruit and will allow imports for the first time.

Quarantine measures for Drosophila suzukii in apricots and plums have not been established, so trade in these commodities from the USA is currently not permitted.

Australia has released the final IRA reports for table grapes from China and for table grapes from Korea. The final PRA report measures apply to these commodities.

Does this give the go-ahead for the importation of all host commodities?

Yes. The release of the final PRA report provides the policy framework to allow imports of host commodities of Drosophila suzukii providing they have approved measures and operational requirements in place.

Any new quarantine measures proposed will need to be accompanied by a submission that supports their efficacy at managing the risk of Drosophila suzukii.

In addition, for commodities that currently do not have existing or previous import conditions, a risk assessment will be conducted to identify all pests associated with that particular commodity.

Does imported food need to comply with Australia’s food standards?

Imported food for human consumption must satisfy Australia’s food standards. Australian law requires that all food, including imported food, meets the standards set out in the Australia New Zealand Food Standards Code. Food Standards Australia New Zealand (FSANZ) is responsible for developing and maintaining the Code. The standards apply to all food in Australia, irrespective of whether it is grown domestically or imported.

Last reviewed: 4 November 2019
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