Biosecurity Advice 2020-P11 - Release of the draft group pest risk analysis for soft and hard scale insects on fresh fruit, vegetable, cut-flower and foliage imports

6 November 2020


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This Biosecurity Advice notifies stakeholders of the release of the Draft group pest risk analysis for soft and hard scale insects on fresh fruit, vegetable, cut-flower and foliage imports.

The department is improving the effectiveness and consistency of the pest risk analysis (PRA) process. A key step in this process is the development of the group PRA approach, which considers the biosecurity risk posed by groups of pests across numerous import pathways. It applies the significant body of available scientific knowledge, including pest interception data and previous PRAs to provide an overarching analysis of the risks posed by groups of pests. 

The draft report is being issued for a 90 calendar day public consultation period, closing on 4 February 2021. The consultation period has been extended from the standard 60 days due to the Christmas/New Year holiday period.

Stakeholders are invited to have their say on the draft report. The department will consider all stakeholder comments received during the consultation period in preparing a final report.

Pest Risk Analysis (PRA) is the process of evaluating biological or other scientific and economic evidence to determine whether an organism is a pest, whether it should be regulated, and the strength of any phytosanitary measures to be taken against it. International Standard for Phytosanitary Measures 2: Framework for pest risk analysis, states that ‘Specific organisms may … be analysed individually, or in groups where individual species share common biological characteristics.’ This is the basis for the group PRA, in which organisms are grouped if they share common biological characteristics, and as a result also have similar likelihoods of entry, establishment and spread and comparable consequences—thus posing a similar level of biosecurity risk.

The group approach to PRA is a ‘building block’ that can be used to review existing trade pathways or be applied to prospective pathways for which a specific PRA is required. For example, it can be used as a component of a commodity-based risk analysis.

This is the third group PRA to be released for public consultation. Group PRAs for thrips and orthotospoviruses, and for mealybugs and the viruses they transmit were finalised in 2017 and 2019, respectively.

This group PRA considers the biosecurity risks posed by all members of the insect families Coccidae (soft scales) and Diaspididae (hard scales or armoured scales) in the insect order Hemiptera, which are associated with fresh fruit, vegetables, cut-flowers and foliage imported into Australia as commercial consignments from any country. In addition, this group PRA reviews the potential for soft and hard scale insects to act as vectors for plant viruses and whether these viruses are quarantine pests for Australia. Soft and hard scale insects and the viruses they transmit can have consequences across a range of crops by reducing yield, quality and marketability.

The draft group PRA identifies 243 soft scale and 331 hard scale species as quarantine pests for Australia. No species of hard scale was found to transmit plant viruses. Eight species of soft scales were identified as being able to transmit a total of four viruses associated with grapevines. However, these viruses are not quarantine pests because they are already present in Australia.

Soft and hard scale quarantine pests were estimated to have an ‘indicative’ unrestricted risk estimate (URE) of ‘Low’, which does not achieve the appropriate level of protection for Australia. This risk estimate is regarded as ‘indicative’ because the likelihood of entry can be influenced by a range of pathway-specific factors (such as the commodity, seasonal considerations, the incidence of pests in specific export production areas, or host range), and must be verified on a case-by-case basis. In some cases, the likelihood of entry may need to be adjusted to take account of these factors. To achieve an appropriate level of protection for Australia, measures will be required for soft and hard scale quarantine pests when the URE of ‘Low’ has been confirmed for a specific plant import pathway.

The draft group PRA identifies measures for soft and hard scale quarantine pests, and alternative risk management options. These may be considered on a case-by-case basis when developing new import conditions for specific commodities, or when reviewing existing import conditions for commodities that are currently traded. These measures are consistent with long-standing established policy for scale insect quarantine pests.

Where measures are required, they include the following options:

  • pre-export visual inspection and if found, remedial action (e.g. suitable treatment) to manage the identified pest
  • a systems approach
  • treatment
  • area freedom.

On-arrival verification will be undertaken to provide assurance that Australia's import conditions have been met and appropriate level of protection achieved. Imported goods that are frequently found to be infested with soft and hard scale insects may be subject to mandatory, pre-export treatment approved by Australia.

The draft group PRA and information about the group PRA process are available on the department’s website. Printed copies of the report are available on request.

The department invites stakeholders interested in receiving information and updates on biosecurity risk analyses to subscribe via the department’s online subscription service. By subscribing to Biosecurity Risk Analysis Plant, you will receive Biosecurity Advices and other notifications relating to plant biosecurity policy, including this risk analysis.


Dr Chris Parker
First Assistant Secretary
Biosecurity Plant Division

Last reviewed: 6 November 2020
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