Italian researchers who have been battling kiwifruit vine canker for years say they are making significant progress in developing a careful strategy for curbing the PSA bacteria now hitting vines on orchards throughout New Zealand.
``Our protocol working is quite well to reduce PSA infection and, in the meantime, to increase kiwifruit production too,'' research coordinator Professor Giorgio Balestra, of Tuscia University at Viterbo told NZPA.
The news came as New Zealand orchardists met today in efforts to develop a containment regime for the bacteria in diseased orchards from the Bay of Plenty to Motueka.
Though details of the research have so far only been published in Italian, Prof Balestra said additional data collected over the past kiwifruit season -- in which the disease ravaged golden kiwifruit orchards -- was being analysed for the project.
``In a short time, I think we'll be ready to develop and spread additional and useful information for growers.''
Researchers and producers in the provinces of Latina, Rome and Viterbo have been trialling containment of the bacteria which causes kiwifruit canker -- scientifically known as Pseudomonas syringe pv. actinidiae (PSA) -- by monitoring 2000 gold kiwifruit vines and 6000 vines of green cultivars.
``We are very satisfied with the results'', said Giovanni Lucci, a trial manager for the Timac Agro Italia horticulture company which has hosted some of the trials.
Producers outside the official trials who had adopted the experimental protocol were also very satisfied with the results, he said. ``We are heading in the right direction to find a solution''.
The researchers have been using copper-based sprays to suppress bacteria, sometimes a spray of copper nitrate alone, or in combination with a range of nutrients, and ``biostimulants'' which help boost the plant's resistance to disease.
Leaves were dosed with nitrogen, phosphonic acid, iron, manganese and zinc and roots were irrigated with a formula of diluted algae extracts, humic and fulvic acids and organic nitrogen.
They aimed to protect the plants from infection and re-infection, and said the stimulation of root development and internal responses in the vines seemed to activate the vines' own defence systems.
Early results showed green kiwifruit grown with the regime were heavier than those on untreated vines, and good containment of the bacteria.
The researchers also found the bacteria seemed to be a greater risk to plants in specific seasons and stages of growth.
Italian researchers develop regime to contain PSA
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