Psa outbreak: Fears copper-spray plan may harm vines

Leaf spot identified which could be the kiwifruit disease Pseudomonas syringae pv actinidiae. Photo / APN

The Ministry of Agriculture and Forestry is preparing to copper-spray kiwifruit orchards affected by the vine-killing Psa bacteria, despite reservations it could do more harm than good.

Copper-spraying was put off today over fears from officials it would defoliate vines.

MAF Biosecurity deputy director-general Barry O'Neil said spraying over Te Puke orchards will begin tonight or tomorrow morning.

According to OneNews, five kiwifruit orchards are currently under quarantine, three of which have confirmed cases of PSA. Twenty others are currently being investigated by MAF.

Growers were still regularly getting in touch with authorities over infection concerns.

Zespri chief executive Lain Jager said as of this afternoon, 135 growers had made inquiries, with 78 of them having suspected PSA cases. The rest appeared clear.

MAF Biosecurity deputy director-general Barry O'Neil said lab test results of samples from nine orchard sites would be returned tomorrow, and by Saturday that would have increased to 40.

Eradication the "number one goal"

OneNews reported that officials will have the results from around 70 orchards by Sunday, which will be enough for authorities to know just how dangerous and widespread the disease is.

MAF was already looking for the disease in other provinces, and if it was found to have become too widespread the third option became a question of how the industry managed the problem.

"We will begin to get a clear picture of that I think by Friday, and a much fuller view perhaps over the weekend," said Mr Jager.

Mr Jager said there were many variables, and obvious questions about when and how PSA had got here, and that it remained possible it had been dormant here for years.

There had been no evidence of the orchardists affected having operated any differently than others, he said.

Dr O'Neil said there was also a possibility that the strain of Psa could be different to those identified overseas.

"It may be that this organism in New Zealand is a far more mild situation, and if we are not able to eradicate, it may be that orchardists will be able to manage this problem relatively easily within normal orchard practice methods."

Mr Jager said the number one goal was to eradicate Psa from New Zealand, and if that wasn't possible, the second option was to try to contain it

Export markets still open

As officials battle to get on top of the potentially destructive kiwifruit vine bacteria outbreak in the Bay of Plenty, export markets have confirmed they don't intend blocking incoming fruit.

Australia had taken a stance that the fruit itself didn't present risks, and Japan and the United States had taken the same stance.

"The only two actions that have been taken to date are actions that I think are quite reasonable and understandable, which is against New Zealand nursery stocks.

"Those actions were taken by Australia and the USA, and not dissimilar to actions we took in 1998 with respect to ensuring nursery stock coming into New Zealand was not presenting a risk to our kiwifruit industry from those countries that may have had Psa."

- NZPA and NZ Herald staff