Three hundred products have been tested and thousands of hours of research conducted but no cure has been found, or is likely to be found, for the kiwifruit vine disease Psa-V.
A total of three hundred products have been tested for Psa-V but no cure has been found.
Barry O'Neill CEO of Kiwifruit Vine Health says the reality is Pseudomonas syringae pv actinidiae is here to stay.
“It's not going away. There is nothing known that will eradicate it and it is unlikely new more tolerant varieties of kiwifruit will be available for at least five to 10 years.”
By mid-January 2047 orchards, 1058 of them in the Te Puke area, had the disease which had also been found in all growing regions with the exception on Whangarei, North West Auckland, Wanganui Horowhenua and South Island.
Grim though that sounds, Barry says other fruit growing industries including pip and stone fruit have contended with similar bacterial diseases for decades and survived.
The kiwifruit industry will never be the same and growing kiwifruit commercially has become more difficult and expensive, but by no means impossible.
Accepting the disease is here to stay doesn't mean a reduction in research and development to find ways to manage it. Work is going on in New Zealand and off-shore, funded by industry, government and companies at levels from practical orchard management techniques to hi-tech scientific research.
Among the 330 products tested since 2010, some have shown promise but unless they are registered by the Ministry for Primary Industries for use against Psa-V they cannot make claims to that effect.
One such product is Citrox BioAlexin which displayed some efficacy against Psa-V in certain varieties of kiwifruit in the KVH Product Testing Programme. However, it does not currently hold a registered label claim for Psa-V control, but is registered and can be used as a foliar fertiliser. The company which makes the organic BioGro approved product says it is designed to aid plant and crop health and quality through improved nutrition. “It assists in the activation of the plants natural protection and defence mechanisms (phytoalexins) during the whole season. Use at times of stress for the plant to ensure the best chance of recovery. BioAlexin can be used on in full season programs for grapes, all fruits, vegetables, cereals, flowers, berry fruit, turf and hydroponics.”
Citrox (NZ) Ltd is currently in the process of obtaining registration of Citrox BioAlexin as a Psa-V control product.
MPI's Agricultural Chemicals and Veterinary Medicines Group says that regardless of the product or substances involved, if something is being used, promoted or trialled as a treatment for disease in any crop plant, it must be registered.
Growers planning to use any product on their vines to treat Psa-V, need to ensure it has been approved for that use by the ACVM group.
In a statement the ministry says: “While this may seem unnecessarily bureaucratic, particularly where kiwifruit growers are desperately trying to preserve their crops and livelihoods, full registration of agricultural compounds is required to ensure the protection of the industry and its markets.
“Where any products are used on commercial crops, there is an increased risk of residues in fruit and with that, comes potential trade impacts. In addition, there is also risk associated with lack of efficacy and plant safety (loss of your vines).
“Should you wish to trial or use any product on vines for the purposes of controlling/managing Psa-V, you must ensure an appropriate approval has been granted.”
“In general, fertilisers are exempt from the requirement of registration unless they are being used for a purpose other than improving the general health of the vine. Fertilisers cannot be used in a manner other than what is specified on the label. A claim for treating disease cannot be made unless the product has been fully registered to support that claim. Anyone applying fertilisers should use them in accordance with the label instructions to manage any potential risks.
“ACVM is committed to helping make the approval process as fast and painless as possible,” the statement said.