Vine-killing canker spreads

The vine-killing bacteria on the nation's kiwifruit orchards is spreading, with 75 properties now showing symptoms of the bacteria threatening to cost the horticultural sector hundreds of millions of dollars.

The disease, known as PSA, has been confirmed on three orchards in the Te Puke region of the Bay of Plenty and movement restrictions have been put on a further two orchards strongly suspected of having the disease.

But Biosecurity Minister David Carter said tonight a total of 75 orchards had made contact about possible symptoms and the Ministry of Agriculture and Forestry (MAF) was investigating.

"We're now seeing it more widespread than we would want to see," he said.

"It looks as though we are dealing with a bigger problem than we thought."

Mr Carter said there was a possibility the bacteria had been in New Zealand for many years and that vines had shown lesser symptoms which had not been recognised until vines were stressed by a cold wet winter.

Mr Carter said his staff was now checking orchards far from the Bay of Plenty, in regions such as Motueka and Northland. Whether the bacteria had reached there was a key issue in the decision on eradication.

If Bay of Plenty orchards have to be managed as diseased, Zespri would need "disease-free zones" outside the region to supply markets such as China, which is likely to refuse fruit it claims could spread bacteria.

In Mt Maunganui, Zespri's director of grower services, Carol Ward, said actions taken to control the bacteria would be directed by MAF "and may well include the removal and destruction of affected materials".

"Zespri and MAF recognise the need to act quickly," she said.

Mr Carter said a decision on eradication would be made by the end of the week.

"While the preferred option of dealing with PSA is eradication, this decision can only be made once the spread of the disease is determined," he said. "We hope to know this by Friday afternoon".

But a New Zealand grower who unsuccessfully battled the disease in Italy's Lazio region, Opotiki Packing and Coolstorage Ltd (Opac) managing director Craig Thompson, said an outbreak there last season killed up to half the vines on some orchards, including one owned by his company.

"It proved to be incredibly virulent and aggressive on gold varieties of kiwifruit in the Italian region," he said.

The Italians had thought removing and burning infected vines would control the outbreak, but "we were too slow and we weren't aggressive enough with the vines we removed that might have been infected".

Mr Carter said that while there was a treatment which could contain the spread of the disease -- a copper spray -- it would only be applied to orchards which were confirmed to be infected.

Mr Carter said he did not want wholesale copper-spraying of orchards, in case the spray stopped fruit being exported when it was harvested next year.

NZPA WGT kca dj mgr

 

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