Psa source: court action considered

Scientific evidence that the vine disease Psa-V originated in China may not be enough for growers to take a court case against the Ministry for Primary Industries.

New Zealand Kiwifruit Growers Inc. president Neil Trebilco says the research just released by the University of Otago is not enough to back a court case over a possible bio-security breach.

File photo.

'This is another important piece of evidence in understanding the disease but the report doesn't identify the vector,” he says.

NZKGI will re-evaluate, in light of the evidence, the possibility of taking the ministry to court, but Neil says it would be necessary to show how the disease arrived in New Zealand and that there was a failure of duty of care.

However, the work done by the University of Otago team in sequencing the genome of Psa-V was a vital piece of work in furthering the understanding of the disease.

'I want to thank the university of Otago team involved in the work and the post-harvest companies which helped finance it. This has provided yet another step in the long war against Psa.”

Neil says what is disturbing is the evidence that the bacteria has the ability to change its virility and mode of action and it is vital that no other altered strain of the disease enters the country.

Minister of Primary Industries Nathan Guy says it is not unexpected that Psa has potentially come from China.

What various studies, including this one, have shown is that it is inconclusive as to exactly how Psa entered New Zealand.

'The Ministry for Primary Industries are continuing to keep a watching brief on the issue of the pathway tracing and will follow up on any new information provided.

'The focus of the Government now is to support the kiwifruit industry the best we can. That is why in 2010 the Government provided $25million, matched by industry, to support the initial response and ongoing research and development.

'We are also working with Kiwifruit Vine Health to effectively implement the National Pest Management Plan.

'Government spending on biosecurity is now almost double what it was in 2000, and last year saw one of MPI's biggest border staff recruitment intakes ever.

'Following the Psa outbreak, MPI commissioned an independent review of import requirements and border processes for kiwifruit plant material. All recommendations from the Sapere report will be adopted, but at the same time the review found that any shortcomings at the border were not necessarily the reason Psa got into New Zealand.”

The Otago University study which shows Psa-V originated in China is published in the international science journal PloS One, and backs findings the university team made in May last year, when it linked the New Zealand Psa outbreak in 2010 to bacteria found in China, but said more data was needed to confirm the link.

Associate Professor Russell Poulter, Professor Iain Lamont and Dr Margi Butler, all from the University of Otago's Department of Biochemistry, have been working with the kiwifruit industry since the Psa (Pseudomonas syringae pv. actinidiae) bacterium was first detected in a Te Puke orchard in November 2010.

The arrival of new advanced genomics technology – through the government funded initiative, New Zealand Genomics Limited – allowed the Otago biochemists to show the New Zealand strain was significantly different from the Italian strain and, therefore, Italy could not have been the source.

Critically, it also put to bed any rumours that New Zealand may have been the source of historical Italian outbreaks.

The university says that through a process of elimination, Chinese pollen appears to be the likely source of New Zealand's outbreak.

The Otago biochemists have been able to source some Chinese Psa samples for sequencing and the results indicate that China is the original source of both the Italian and New Zealand outbreaks.

More recently, Psa has been confirmed in Chile and work has begun on sequencing these strains. Preliminary data suggests that the Chilean strain also originates from China.

"These findings paint a clear picture of an independent Chinese origin for both the Italian and the New Zealand outbreaks and suggest the Chilean strains also come from China," says Russell.

The researchers are now sequencing a further 20 strains, mostly from China but also Korean and Turkish strains.

"Some Psa may be inherently more virulent due to the particular ICE they carry. This has worrying implications as strains of kiwifruit that are resistant to one type of Psa might not be resistant to another," Dr Poulter said.

"This means strict border control by kiwifruit-producing countries is more important than ever."



Posted on 01-03-2013 13:32 | By Capt_Kaveman

person who imported the pollen to start with , biosecurity for letting it in,all orchards around where it start to be allow to travel freely including govt not closing off the district including all ways in or out of this orchard, as what was stopping someone driving onto an infected orchard then travel to another anywhere in nz?

PSA Source Scientific Evidence

Posted on 01-03-2013 17:25 | By Zestco

I have read the Otago University publication. Your quote of Dr. Poulter differs from what I understood from the publication. The authors provide scientific evidence- That the Italian, New Zealand and Chilean PSA had a common origin from China but subsequently, have acquired some additional genetic material from the local (Italy, New Zealand, Chile) environment. This Chinese genealogical form evolved about two decades ago, therefore in terms of evolution - 'recent” The revelation that the current PSA shared a common recent ancestor in China compels the industry to reexamine the probable plant material carrier (vector) of the disease into New Zealand and Italy. I gather from two Plant & Food / Zespri Publications (Hort16A' Leader Dieback Italy Year 1 Manning M, Riccioni L and Spinelli R June 2006 " and Reducing the threat from New Zealand vine diseases Manning M, Casonato S, Currie M, Weber P. March 2010 ) the new strain of PSA has been around for more than 10 years in Italy and in New Zealand. A common factor is the 1st symptoms of PSA were seen on Hort 16A, both in Italy and NZ in or before 2004. This implies that the common factor (or vector) is Hort16A. Could it be that Plant & Food Research may have brought in (PSA) on asymptomatic scion wood from China over (approximately) the last 20 years? Another question that arises from the two Zespri publications is why was this 'new disease” incidence not reported to Biosecurity New Zealand or the Italian authorities at the time? The authors claim they did not know what the disease was. Would it not be mandatory to report a 'new unknown disease”? I deduce that imported pollen which arrived much later into NZ is clearly not the 'vector”. The pollen companies have been unfairly victimized! It is time to focus on Hort 16A as the primary carrier of the disease into NZ and why a 'unknown disease” was not reported to Biosecurity NZ?. It is time for a Royal Commission of Inquiry over the whole debacle of PSA, copper, streptomycin, elicitors, new varieties and now the marketing issues in China.

PSA Source Scientific Evidence

Posted on 02-03-2013 09:31 | By Zestco

Dear Editor, Could you please add my name and phone number under my comment. Nathan Balasingham 09 2383893 thanks Zestco

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