Alarm as Psa confirmed in Bay

Hawke's Bay kiwifruit orchardists are on heightened alert after an outbreak of the devastating vine-killing disease Psa-V in an orchard near Taradale.

A positive test result was confirmed yesterday and industry organisation Kiwifruit Vine Health (KVH) has established a controlled area that includes 43 kiwifruit orchards in the Hawke's Bay region.

It said the disease was found on an orchard near Taradale on Hort16A gold-variety vines.

KVH was set up to manage the response to Psa following its devastation of kiwifruit orchards in the Bay of Plenty, the centre of the Kiwifruit industry in New Zealand. It has since spread to the Waikato.

About half of the nation's vines have been infected since 2010, many cut back to stumps - considered the best way to tackle the disease. Many planted other crops entirely, including the new kiwi berry.

KVH chief executive Barry O'Neil said the spread to Hawke's Bay was very disappointing.

"Psa is without doubt a major challenge and it's having a huge impact on growers.

"Unfortunately autumn and spring are times of the year when we see the very worst of both its spread and impacts."

KVH will hold a meeting for Hawke's Bay growers on Monday.

"Based on the symptoms seen in the orchard, it is possible infection may have been present, but undetected in the area, for at least six months prior to identification this week.

"In many cases, symptoms are not visible for some time after infection, particularly over the winter dormancy period. Therefore, growers can't afford to be complacent, and should act as though Psa-V could be present in their area. Growers must be proactive to protect their orchards. Doing nothing is not an option."

Hawke's Bay Fruitgrowers Association kiwifruit chairman Peter Olsen said he did not know what Monday's agenda would be "but it is a very significant issue, both for Hawke's Bay growers and the industry".

He said many growers had grafted their vines to other varieties, particularly to G3, which is also a gold variety more but more resistant to the disease.

"Zespri have been encouraging them because it is a way of countering the spread of Psa - Hort16A is just so susceptible."

Hawke's Bay growers have not been complacent over the disease threat. Signs informing of the restrictions have been displayed wherever kiwifruit vines have been grown.

The Hawke's Bay Fruitgrowers Association wrote to councils and utility companies saying unarranged visits were no longer possible and staff had to be aware of orchard hygiene requirements.

In the association's newsletter, growers were told the responsibility was theirs and "gates should be chained and padlocked when you or your staff are not on the property".

Taradale kiwifruit orchardist Mark Ericksen has switched to the G3 variety but was "upping his spraying" as a precaution. Mr Olsen said he was keen to find out how the disease had spread to Hawke's Bay.

"I have no idea but you would have to suspect human transmission - perhaps pruning gear from people who have moved here."

Kiwifruit is very difficult to pollinate because blossoms are not very attractive to bees. Often pollen is mechanically blown and it is theorised infected pollen imported from overseas brought the disease to New Zealand.