Jamie Morton

Jamie Morton is science reporter at the NZ Herald.

New growing sites may help save kiwifruit

The Psa bacterium is here to stay so growers must manage it, says horticulture expert.

Ian Warrington says there is little, if any, chance of eradicating Psa. Photo / Alan Gibson
Ian Warrington says there is little, if any, chance of eradicating Psa. Photo / Alan Gibson

Kiwifruit growing regions outside the Bay of Plenty could soon play bigger parts in a $1 billion-a-year industry battling a bacterial scourge that is here to stay.

Professor Ian Warrington, co-president of the International Horticulture Congress, has suggested ways New Zealand could live with Psa-V, which has now spread as far as Hawkes Bay since its discovery in heartland Te Puke nearly two years ago.

"The importance of different growing regions in the future will be far more so than currently," he said.

But it was "very unlikely" the industry's heartland could be shifted away from the Bay of Plenty to cleaner ground.

"I'm talking about diversifying so we've got alternative growing areas where your integrated kiwifruit industry has a chance of getting supply from different regions where climates and seasons may have had different impacts on crops.

"And we'd be talking about innovative growers prepared to take the risk of getting into a new crop or perhaps, if we are able to be very certain about the resistance of new cultivars, then having the courage to put those into new areas and keeping the industry clean."

He put the chances of eradicating Psa at "pretty much zero".

"The question is, how can various management and chemical techniques be used to suppress it to an economic level where growers can survive and have a viable industry?"

More than $10 million has gone into an industry research and development programme to fight Psa, involving testing more than 300 products against it.

As of this week, 1669 orchards across the Bay of Plenty, Franklin, Waikato, Coromandel and Hawkes Bay had tested positive for Psa-V, covering about 59 per cent of New Zealand's kiwifruit hectares.

The long-term impact was this year estimated at between $740 million and $885 million, while up to 470 jobs each year over the next three years would be lost.


Psa around the world

Italy: Found in 1992, now widespread in main growing regions.

France: Found in 2010, 18 per cent of industry now affected.

Japan: Different strain found in 1989, managed by cutting back vines.

South Korea: Severely damaged its industry in 1992, now mostly confined to two regions.

Chile: Eight orchards tested positive this year.

- NZ Herald

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