Biosecurity Advice 2018-18 - Announcement of the pest risk analysis for bacterial pathogens in the genus Xylella

2 August 2018

This Biosecurity Advice announces the pest risk analysis for bacterial pathogens in the genus Xylella.

The Department of Agriculture and Water Resources (the department) expects to release a draft report for a 60 day public consultation period in early 2019.

The importation of nursery stock and plant tissue culture is currently subject to emergency measures to manage the risk presented by the bacterial pathogen, Xylella fastidiosa.

This pest risk analysis was initiated to: assess the risks presented by Xylella fastidiosa and its subspecies; evaluate the emergency measures; consider ongoing phytosanitary measures; and ensure any ongoing phytosanitary measures are technically justified. Since this pest risk analysis was initiated, a second species of Xylella, X. taiwanensis, has been newly identified. Worldwide research on Xylella species, subspecies and strains is continuing, and for this reason the scope of this pest risk analysis has been expanded to include all Xylella species.

The department has regulated Xylella fastidiosa for more than 35 years in imported nursery stock, such as grapevines, peaches and plums, from countries known to be hosts at that time. In 2013, Xylella fastidiosa was detected in Europe and in subsequent years began causing significant and ongoing economic losses in olive and almond orchards in Italy and France. Therefore, the department implemented emergency measures for live plant material (excluding seed) of around 20,000 different species, in 89 plant families, coming from high-risk countries. Information about the changes made to import conditions for Xylella host material is available on the department’s website.

Xylella bacterial pathogens can infect more than 400 different plant species. The diseases caused by Xylella have had different names depending on the host species, including: Pierce’s disease, almond leaf scorch, bacterial leaf scorch, citrus variegated chlorosis, olive quick decline and olive leaf scorch. In Europe and the Americas, Xylella species have caused significant damage to amenity trees and numerous crops such as grapes, citrus, plums, olive, almonds and pecan. The Xylella host range is expanding each year to include many horticultural, agricultural crops, ornamental plants and Australian species grown overseas (such as Eucalyptus and Acacia). Due to the severity of disease reported across a wide range of host plants, Xylella fastidiosa is considered the number one pest threat to Australian horticultural and agricultural industries, and to the environment.

More information about this pest risk analysis is available at the department’s website.

The department expects to release a draft report for public consultation in early 2019. A Biosecurity Advice will be issued to invite comment at that time. The department will consider all stakeholder comments received during the consultation period in preparing the final report.

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

Dr Marion Healy
First Assistant Secretary
Biosecurity Plant Division

Telephone: 1800 900 090 (option 1, option 1)

Email: Imports
Last reviewed: 30 September 2020
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