There's no Psa in Whangarei - botched tests

By Lindy Laird


The kiwifruit killing disease that has wreaked havoc on New Zealand's industry has not shown up in Whangarei despite botched tests giving local growers the fright of their lives.

Disease watchdog and adviser group Kiwifruit Vine Health (KVH) ordered the retesting of material from Whangarei and Kerikeri orchards after being suspicious of inconsistencies in Psa-V laboratory test results from late October. A lack of progression of any Psa-V symptoms on orchards in those areas also led to a review of laboratory Psa-V testing processes.

Four Whangarei growers were given the all-clear before Christmas after two laboratories delivered consistent results, and the general testing process was reviewed.

One of those orchardists, district KVH co-ordinator Alan Horsfold said the news was great for Whangarei growers.

"There is no Psa-V in Whangarei. That's a very positive thing for the local industry."

It is believed cross-contamination of slides caused a blind testing programme of samples to return "positive", "not detected" and a "weak positive" results in November, until a new regime of tests and audits was ordered.

Mr Horsfold said he believed that despite the worrying mix-up, the testing process for Psa-V is robust.

The four Whangarei orchards have returned to "exclusion zone" status after being treated as preliminary containment zones following the incorrect results.

"We are back to where we were, taking every precaution possibly," Mr Horsfold said.

Growers had learned to accept stringent precautions against the industry-crippling bacterium. Local growers recently met and reaffirmed their protocols related to pollen and any plant material, orchard hygiene and the movement of equipment and workers.

Whangarei, north west Auckland and Nelson are the only kiwifruit growing areas in New Zealand that are Psa-free. It was first found in the Bay of Plenty two years ago and has affected 69 per cent of New Zealand orchards.

The outbreak has been traced to China.

University of Otago scientists have confirmed the strain originated in China and may have been imported in pollen in June 2009.

There are 102 orchards in a controlled area in Kerikeri established after the bacterial infection was confirmed on three orchards there last year.

Meanwhile, Northland growers look set to cash in after the larger growing areas have taken a body blow. The expectation is that even with a smaller crop, the export return on the green variety will be as much as in previous, more productive years while prices will be up even further for the lucrative but Psa-vulnerable gold variety.

- NORTHERN ADVOCATE

© Copyright 2014, APN New Zealand Limited

Assembled by: (static) on red akl_a5 at 24 Apr 2014 19:09:59 Processing Time: 1466ms