Plant & Food Research scientists have found a way to speed up the kiwifruit vine's defence against PSA disease.
It's similar to the way people boost their immune systems by taking vitamins.
About 20% of New Zealand's kiwifruit orchards have now been infected with PSA.
Scientist Tony Reglinski says this latest research has found the vines do resist the disease, but react too slowly to it.
He says field tests are underway on a product which is injected into the trunk of the vine, boosting its immune system and priming it for defence against disease.
If successful, Mr Reglinski says it would be used in conjunction with other protective sprays to slow down the disease progress until a long-term resistant kiwifruit variety can be found.
Latest figures from Kiwifruit Vine Health show the virulent form of PSA has now been confirmed on 689 orchards spread throughout the Bay of Plenty region, with a marked increase of 255 new cases this week.
The agency is still waiting on a test result from an orchard in Kerikeri which will determine whether the Northland region remains clear of PSA V.