Kiwifruit infection found in fresh area

Psa has been found well outside of the area originally thought to be infected. Photo / APN

The discovery of a form of kiwifruit vine disease Psa in an orchard in Waihi, well outside the nearest infection zone, has raised grim possibilities for other growing regions outside the Bay of Plenty.

But industry group Kiwifruit Vine Health (KVH) says the identification of the virulent Psa-V at a green kiwifruit orchard south of the Hauraki township could provide clues to help battle the bacterial canker.

The find has forced KVH to define a new "priority zone" south of the town and extend a "high-risk zone" across the Waihi region, covering about 190ha of orchards.

The priority zones, now covering Te Puke and Tauranga, are sites confirmed with Psa-V, while high-risk zones mark adjoining areas that are the next most at risk.

KVH chairman John Burke said symptoms from the orchard were "pretty typical" of the vicious strain.

"We are doing some tracing studies and taking an in-depth look at what possible links we could have with the spread of the disease, although it's most likely it's occurred through inadvertent plant movement at some stage."

The infected vines would be bagged and burned and, while there were no orchards adjoining the site, other growers around Waihi had been put on alert.

They would discuss the development at a meeting in the town this afternoon.

"Obviously there's now a spotlight on that area in terms of monitoring and surveillance, and we're trying to prevent any movement of plant material to and from there," Mr Burke said.

The affected orchard had been "pretty tightly run" since the outbreak was discovered in Te Puke in November - raising a question over whether Psa had been in New Zealand long before then.

"There's a real risk that if the disease had been in New Zealand for a period of years, then you've got all of that period where there could have been links between potentially infected orchards in Te Puke and other orchards around the country.

Mr Burke said a better picture of how long Psa had been in the country would "give us a few more clues to add to the puzzle".

"We are working hard on finding some solutions and there are strands of stuff already coming through, but it may take a little bit of time before we can get some information that we can feed out to the industry."

The latest blow came when there was already wide concern among growers, Kiwifruit Growers Incorporated chairman Peter Ombler said.

"Growers are very concerned, but equally, they're gritting their teeth and doing what they can to protect themselves."

The spread of Psa to Waihi was a "big shift".

"What it's shown is that it has the potential to move a long way and it will only heighten the awareness of growers in Kerikeri or Nelson."