Grower begins to destroy kiwifruit

The first grower confirmed to have diseased kiwifruit vines has cleared 4000sq m of his Te Puke orchard in an attempt to stop Psa spreading. Photo / APN

The first grower confirmed to have diseased kiwifruit vines has begun to cull large sections of his orchard as biosecurity officials say full-scale eradication looks increasingly difficult.

Russell West has cleared 4000sq m of his Te Puke orchard in an attempt to prevent the spread of Psa.

His concern over brown spots on his kiwifruit leaves was the spark for the massive investigation into the spread of the vine-killing disease in the North Island.

Yesterday he described the "terror" of realising the presence of the pathogen in his backyard, saying he immediately "thought he needed a whisky".

"What we were frightened of getting in New Zealand is here. Now we're faced with managing it.

"I would really like to know how it got in the middle of the orchard ... There's no sign of any pattern of infection. No pattern that makes sense."

Ministry of Agriculture and Forestry approval for Mr West to cut his vines came as the Government opted for "aggressive containment" of Psa, rather than taxpayer-funded eradication.

"Obviously eradication of the disease is what we all want and this is certainly not being ruled out," Biosecurity Minister David Carter said yesterday. "But with around 500ha now infected, eradication is looking increasingly difficult, at least in the short term ... aggressive containment is the best option for now."

Maf and the kiwifruit industry were working together on containment, including removal of infected plant material and its safe disposal; spraying infected vines; controlling the use of artificial pollination and advice on the use of beehives for pollination; and controls on the movement of people and equipment around infected properties, said Mr Carter.

Zespri corporate and grower services director Carol Ward said the disease was spreading through the vines, and there were symptoms "of a red ooze".

On some orchards, the disease has progressed from leaf spotting to the collapse of the vines, with some bleeding a red liquid from cankers.

The source of the pathogen is still not known. Kiwifruit experts suggested last week that Psa might have lain dormant in vines for years, but historical vine samples dating back to 1980 had shown no evidence of it so far.

Maf was investigating the possibility that Psa had been transmitted to the vines by artificial pollen.

Response manager David Yard said yesterday that preliminary tests had indicated Psa was present in imported and local pollen which had been used on last season's crop. However these tests were inconclusive and Maf had called for retesting. In the meantime it was cautioning growers against the use of artificial pollen.

Another theory was that the pathogen travelled back to New Zealand with growers or Zespri officials who observed infected orchards in Italy.

THE NUMBERS

11 orchards confirmed with Psa
3 other orchards quarantined
28 orchards cleared by Maf
93 orchards being investigated
195 orchards with suspected symptoms of Psa

- additional reporting: NZPA