Kiwifruit disease in Whangarei orchard

BLOW FOR WORKERS: Whangarei's kiwifruit industry employs about 200 people, with numbers swelling in summer. PHOTO FILE

Growers are "shell-shocked but determined" at news a kiwifruit killing disease has infiltrated Whangarei - formerly the last region in the North Island free from the infectious Psa bacteria - putting the $38 million a year industry in Northland under more pressure.

There are 49 kiwifruit orchards in Whangarei, about 144 canopy hectares. The industry directly employs about 200 people year-round in Whangarei, with numbers swelling considerably during the harvest season. About 140 kiwifruit orchards in Northland produce about 5 per cent of the national crop and earned about $38 million last season.

New Zealand's 13,000 hectares are about 80 per cent infected with Psa (Pseudomonas syringae PV actinidiae) vine disease, first discovered in New Zealand in 2010.

The disease, found at an as-yet unidentified Maungatapere orchard, could reduce production, means orchards would need additional quarantine measures and rules out growing a particularly susceptible strain of golden kiwifruit.

Maungatapere orchardist Patrick Malley said growers had been readying themselves for the news for some time.

The infection did not affect export markets, as it could not spread via fruit.

"No one's going around screaming," Mr Malley said.

"Yet it's still a shock when it finally happens.

"As many growers as possible are getting behind the grower with the infection."

A golden kiwifruit variety, Hort 16A, was particularly susceptible to the disease and was the host of the current outbreak.

Mr Malley said for orchards that had not already begun to switch from Hort 16A, the find would be a particularly hard blow.

"There is a large cost [to replanting] and it's mainly the loss of income. There's no money for the 1-2 years it takes [a new variety] to start growing," Mr Malley said.

Staff from Kiwifruit Vine Health (KVH) - the organisation charged with containing the disease - would be conducting further testing at Maungatapere this weekend to determine whether other orchards were infected. Test results were expected by Tuesday at the latest, when an industry meeting would be held.

"Based on the symptoms found - die back and exudate - it's likely the disease has been in the area for some time and the symptoms are now starting to show," said KVH chief executive Barry O'Neil.

All growers in the region had been alerted to the bacteria's presence, discovered as part of the grower's seasonal disease checks, Mr O'Neil said, adding there was "absolutely no evidence" the grower had done anything negligent.

This spring, KVH had reported more widespread infection in the positive regions, so the Whangarei outbreak was not entirely unexpected, he said.

The disease spread through the moving of plant material between orchards, including new plants and budwood, or contaminated equipment. The disease could also spread up to 10km on the wind, making it "extremely difficult to contain", Mr O'Neil said.

He said last season had seen record kiwifruit production in New Zealand, despite Psa - a fact growers could take heart from. Growers were being advised to monitor their orchards, maintain strict hygiene procedures, implement a spray programme and not move any plant material or contaminated equipment between orchards.