Wollemia nobilis (Wollemi Pine) - Biosecurity New Zealand
Wollemia nobilis (Wollemi Pine) - Biosecurity New Zealand
Wollemia nobilis (Wollemi Pine) - Biosecurity New Zealand
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It is possible that a serious infection of a Botryosphaeria species could kill the host and<br />
effectively prevent the host and the associated disease from establishing in <strong>New</strong> <strong>Zealand</strong>.<br />
This would only be the case for the most pathogenic species of Botryosphaeria found on<br />
<strong><strong>Wollemi</strong>a</strong> <strong>nobilis</strong> nursery stock. It is unlikely that a Botryosphaeria infection would become<br />
necrotic in the host and therefore not be able to spread from the host into the <strong>New</strong> <strong>Zealand</strong><br />
environment, as species of Botryosphaeria can act as an endophyte. The only remaining<br />
option for avoiding exposure is if the host plants are not moved into the <strong>New</strong> <strong>Zealand</strong><br />
environment. As the intention of any importer would be to plant the imported <strong><strong>Wollemi</strong>a</strong><br />
<strong>nobilis</strong> nursery stock into the <strong>New</strong> <strong>Zealand</strong> environment, this final limitation to exposure is<br />
removed.<br />
11.2.4 Establishment Assessment<br />
As indicated in the exposure assessment, the intention of any importer would be to plant the<br />
imported <strong><strong>Wollemi</strong>a</strong> <strong>nobilis</strong> nursery stock into the <strong>New</strong> <strong>Zealand</strong> environment, therefore<br />
allowing any Botryosphaeria infection to establish a viable population.<br />
11.2.5 Conclusion of Exposure and Establishment Assessment<br />
Given that the imported and contaminated <strong><strong>Wollemi</strong>a</strong> <strong>nobilis</strong> plants themselves can act as the<br />
agent for exposure and establishment, and the intention of any importer would be to plant the<br />
imported <strong><strong>Wollemi</strong>a</strong> <strong>nobilis</strong> nursery stock into the <strong>New</strong> <strong>Zealand</strong> environment, the likelihood of<br />
exposure and establishment is very high and therefore non-negligible.<br />
11.2.6 Consequence Assessment<br />
In the context of the pathway for importing nursery stock contaminated with Botryosphaeria<br />
sp., any potential consequences to people, the <strong>New</strong> <strong>Zealand</strong> environment, and the<br />
<strong>New</strong> <strong>Zealand</strong> economy will only become apparent after establishment and some degree of<br />
spread.<br />
Potential for spread<br />
Botryosphaeria species can produce abundant conidia on the surface of infected stems or<br />
fruits. The majority of the ascospores and conidia are dispersed by air and rainwater,<br />
respectively. Usually, spore discharge occurs just after periods of surface wetness.<br />
Waterborne ascospores and conidia may be present in rainwater run-off from diseased and<br />
pruned limbs. The transmission of Botryosphaeria within and among adjacent plants may<br />
occur through stem run-off, raindrop splashing and pruning equipment. Similarly, the longdistance<br />
transmission of this fungus may occur through air, pruning equipment, insects and<br />
birds. Species of Botryosphaeria are considered in many cases to have a wide potential host<br />
range, making potential hosts widely available. A species of Botryosphaeria introduced into<br />
the <strong>New</strong> <strong>Zealand</strong> environment from <strong><strong>Wollemi</strong>a</strong> <strong>nobilis</strong> nursery stock would be expected to<br />
spread relatively rapidly over its maximum potential range.<br />
Import Risk Analysis: <strong><strong>Wollemi</strong>a</strong> <strong>nobilis</strong> (<strong>Wollemi</strong> <strong>Pine</strong>) Araucariaceae Nursery Stock from Australia 14 March 2008 Page 107 of 193