Kiwifruit growers facing the industry's biggest biological threat are being asked to take a brave punt - cut out the vulnerable gold kiwifruit vines that have been the industry's stellar performer and invest in a new variety that might also succumb to the destructive bacteria Psa-V.

Licences for the new G3 variety were issued this week despite vine failures at two G3 orchards near Te Puke, the heartland of an industry that is an important export earner and the biggest driver of the Bay of Plenty economy.

Gold growers who managed to get a crop to market last year have just received their last payments and face a two-year wait to get a partial crop from the new G3 variety - if it survives the critical first spring.

The cost of converting to G3 is estimated at $60,000 a hectare but gold growers have little choice but to convert as there are no buyers for the hundreds of Psa-damaged orchards.


Up to 120 growers in the heavily indebted gold sector are expected to be refused further bank loans because their property values have collapsed.

But the Government has refused to declare Psa an "on-farm adverse event" which would give the worst-hit growers financial and other aid.

The toll on growers is such that industry leaders have prepared suicide prevention strategies and guidelines on where to find help.

Many growers are nearing retirement age and face rebuilding their orchards with savings, or remortgaging.

Scientists are confident G3 will withstand Psa better than the existing Hort16A variety, and say they have isolated the circumstances that caused G3 to struggle at two trial orchards.

The vine-killing bacteria that arrived in 2010 has run rampant through the high-value gold orchards around Te Puke.

But last spring it also attacked green kiwifruit vines, affecting yields in the just-completed harvest.

The disease has spread to Opotiki, Katikati and Tauranga, where it is expected to prove just as destructive. It has also been found in south Auckland but has yet to show up in Northland or Hawkes Bay, the other main kiwifruit districts.

A Ministry of Primary Industries investigation has been unable to pinpoint how the bacteria slipped into the country in 2010, two years after a devastating outbreak in Italy.

Both the Italian and New Zealand outbreaks are thought to originate from a Chinese strain.

Kiwifruit exports earned $996 million in 2010 but production has fallen for the past two years and is expected to slump next year because about 1600ha of the Hort16A gold variety have been removed.

Infected kiwifruit vine

Airborne bacteria which invade plant vascular system and cut off water supply, causing it to wither and die.

* Number of affected orchards: 1218

* In Te Puke: 923

* Other affected areas: Whakatane, Opotiki, Katikati, Tauranga, South Auckland.

* Hectares affected: 6362, 46 per cent of area planted in kiwifruit.

* By variety: 54 per cent of gold kiwifruit canopy, 42 per cent of green.

Source: Kiwifruit Vine Health