Draft Import Risk Analysis - Biosecurity New Zealand

5.1.2.5. Risk estimation
The risk of ALSV being introduced into New Zealand with Malus budwood and causing
unwanted impacts is considered non-negligible mainly due to the lack of available
epidemiological information to show otherwise. However, the above risk estimation is subject to
review when further information on distribution, biology and potential impact becomes
available.
5.1.2.6. Assessment of uncertainty
There is considerable uncertainty around the taxonomy, biology, distribution and epidemiology
of this virus. As such this risk assessment should be reviewed once further relevant information
becomes available.
5.1.3. Risk management
5.1.3.1. Risk evaluation
Since the risk estimate for ALSV associated with imported Malus nursery stock is nonnegligible,
options for phytosanitary measures are provided for consideration.
5.1.3.2. Option evaluation
There are conceivably a number of management options available for ALSV on imported Malus
nursery stock. The following risk management options are assessed:
a. No phytosanitary measures required if the non-negligible level of risk is considered
acceptable;
b. Pest free area (PFA) (see section 4.3.7 for background): Malus nursery stock is imported
from areas that they are free of ALSV;
c. Pest free place of production (PFPP) (see section 4.3.7 for background): Malus nursery
stock is imported from a place of production that is free of ALSV;
d. Virus indexing of mother plants either prior to export to New Zealand or on arrival in
New Zealand in a post entry quarantine facility.
e. Inspection of mother plants.
No phytosanitary measures required
The level of assessed risk from ALSV is non-negligible mainly due to the lack of available
information on this disease agent. This risk analysis recognises that given the level of
uncertainty around the epidemiology of ALSV the low level of associated biosecurity risk may
be considered acceptable.
Pest free area (PFA)
Given the paucity of information available on the epidemiology of ALSV it does not seem likely
that, in the absence of a reliable low cost method for detecting and identifying the presence of
this virus, a reliable PFA determination could be obtained. Should an appropriate detection and
identification method be identified, a PFA declaration could be considered an effective
phytosanitary measure.
Pest free place of production (PFPP)
Given the paucity of information available on the epidemiology of ALSV it does not seem likely
that, in the absence of a reliable low cost method for detecting and identifying the presence of
this virus and knowledge of potential vectors, a suitably reliable PFA determination could be
obtained under most circumstances.
DRAFT Import Risk Analysis: Viruses, Viroids, Phytoplasma, Bacteria and Diseases of
Unknown Aetiology on Malus Nursery Stock
August 2009 Page 27 of 203