Kiwifruit growers will have to learn to live with Psa, just as other growers have to cope with crop diseases.
That's the view of Katikati Fruitgrowers Association chairman Hugh Moore, who says the spread of the kiwifruit vine disease to Katikati was inevitable.
"It was just a matter of time before it was found here," said Mr Moore, a fruitgrower in the Katikati area for 40 years.
This week, Kiwifruit Vine Health, the body set up to co-ordinate management and control of Pseudomonas syringae pv actinidiae (Psa), said the disease had been confirmed in Katikati and Horowhenua orchards for the first time.
The same disease caused widespread vine losses in the Lazio district of Italy.
Mr Moore said kiwifruit orchardists now faced "the real world of fruit growing".
"Pipfruit growers have for years had to cope with bacterial diseases, including fire blight, and we in the kiwifruit industry now have to do the same.
"I was a pear grower here at Kauri Point for 15 years and managed Erwinia amyloura (fire blight), which acts in a similar manner to Psa during cold, wet winter conditions.
"The controls that our kiwifruit industry is recommending now are identical to those that every pear and pipfruit grower worldwide has used for decades.
"The controls and industry drive at present is critical to understanding this disease, along with the support of Biosecurity NZ to isolate and gauge how widespread and severe this problem is."
Zespri and Maf Biosecurity hadn't over-reacted to the discovery of the disease on a Te Puke orchard on November 5, Mr Moore said.
"Quick action when this thing was first discovered was essential, even though it might have been with us for years."
Cutting out and burning diseased vines, changing orchard practices including sterilising pruning and girdling tools and more winter "clean-up sprays" were among the answers to controlling Psa, he said.
Mr Moore believes most diseases, including Psa, are present all the time and rise and fall with weather conditions and seasons.
"Plant stress can also be a factor, just the same as illness in humans."
Those stresses could include "girdling" vines - cutting into the trunks to stress the plants into producing more fruit.
"There are about 50 different types of this particular bacteria. The leaf symptoms of another disease PV are 'identical' to Psa and were called bacterial leaf spot in 1994, also fungi infections with similar symptoms were recorded by Hawthorn in 1982.
"The statement by many older growers that they have seen the same leaf conditions before is very true whether they were Psa, PV, PSS or a fungal infection," he said.
"As an industry we now need to produce data tables of weather conditions that highlight when Psa could strike again (similar to the Mills tables for blackspot on pipfruit), so that action can be taken once research is complete."
INFECTION UPDATE
- 107 orchards have tested positive for Psa.
- Most (about 75 per cent) are within a 23km area south of Te Puke township.
- Psa identified in Hawke's Bay, Tauranga, Whakatane/ Edgecumbe, Waikato, Golden Bay, Motueka, Gisborne, Katikati and Horowhenua.
- 44 of the 107 Psa orchards grow green fruit, the rest are gold orchards.
- Most Psa considered display primary symptoms - leaf spotting.
- Up to 30 orchards demonstrating primary symptoms have removed infected vines.
- Three orchards with advanced Psa have cut significant canopy area and removed infected materials.
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