THE potato disease zebra chip has crept alarmingly close to Australia with Norfolk Island officials confirming its presence.
A quarantine survey on the island, which is about a three hour flight from Australia’s east coast, detected the Zebra chip causing bacterium, Candidatus Liberibacter solanacearum, and its insect vector, the Tomato-potato psyllid (Bactericera cockerelli).
The survey was conducted in 2014 by Norfolk Island biosecurity personnel in conjunction with researchers from the Plant Biosecurity Cooperative Research Centre (CRC) and Queensland Alliance for Agriculture and Food Innovation (QAAFI).
During the survey, Plant Biosecurity CRC researchers Dr Andrew Geering and Dr John Thomas set insect traps.
The tomato-potato psyllid (Bactericera cockerelli) was recognised in trap contents by Federal Government entomology colleagues.
“The insect and the disease would be major threats to Australian growers if they arrived on the mainland,” Dr Geering said.
There are strict quarantine measures in place for movement of goods between Norfolk Island and Australia
It’s thought the psyllid could have come from New Zealand, arriving on illegally imported plant material or in cargo.
The psyllid and bacterium are widely spread at varying densities across the island with no likelihood of eradication possible with the available resources.
Biological control options for the psyllid are however being considered by the Norfolk Island Government to reduce population levels.
“While it’s a worrying incursion, it does give us a chance to identify the best management strategies for this pest in a sub-tropical environment,” Dr Geering said.
“Initial observations are that the disease situation in the colder climate of New Zealand is slightly different to that on Norfolk Island.
“The disease epidemiology on Norfolk Island is much more like that which could occur in Queensland.
“Understanding the hosts and spread of the psyllid will give us a real advantage in preparing for any possible Australian incursion.”
While the Tomato-potato psyllid has an extensive host range, solanaceous plants such as potatoes, tomatoes and capsicum are preferred targets.
The psyllid is currently found in North and Central America, and in 2006 it was detected in the Auckland region of New Zealand.
There have been no detections of this psyllid in mainland Australia.
Zebra chip has been estimated to cost New Zealand potato growers some $200 million dollars between 2006 and 2012.
Ausveg has previously been very vocal about the threat posed by New Zealand potatoes.
But Ausveg communications manager Andrew MacDonald the organisation was looking at the discovery as an opportunity.
“While any discovery of the Tomato potato psyllid (TPP) is concerning, the fact it has been detected on Norfolk Island during this major quarantine survey puts us on the front foot in terms of preventing the pest from reaching mainland Australia,” Mr MacDonald said.
“Ausveg remains deeply concerned about the potential impact of the TPP on the Australian potato industry and is of the view that every available measure should be taken to prevent its arrival here.”
“Infection by the Zebra chip bacterium leads to reduced plant health and discolouration of tubers, rendering them unsalable.
“The discovery highlights the ongoing risks associated with the importing of fresh potatoes into Australia from New Zealand and is further evidence of why these imports should not be allowed to occur.”
“This discovery on Norfolk Island highlights the importance of remaining vigilant to ensure the TPP does not make its way onto mainland Australia, and we will continue working with all relevant parties as part of ongoing efforts to ensure the Australian potato industry remains free of the TPP.”