Kiwi producer company Donato Mariani & figlio, comprising of around 20 hectares between the municipalities of Lanuvio and Velletri (Lazio), is located in one of the areas that were hit the hardest by kiwi bacteriosis (Psa) in 2008, when the disease first struck the region.
In the Winter of 2008, because of the Pseudomonas syringae pv. actinidiae disease, Mariani's yellow cv Hort 16A kiwis were damaged.
The grounds are in fact located in an area particularly affected by freezing temperatures during Winter which, as is known, make the bacteria more aggressive.
Following the infection, many hectares were uprooted.
Yellow cv Hort 16A kiwis were strongly damaged and therefore many hectares were removed.
As Dr. Marco Scortichini, bacteriologist from Rome's CRA, comments, "after trying and failing to grow yellow A. chinensis kiwis again because the variety was rather susceptible and the disease continued to outbreak, the orchard was almost entirely converted to green cv Hayward kiwis. Preventive measures were taken immediately and agronomic techniques were used to reduce the risk of a Psa infection."
Hayward trunk healed by removing sick parts and protecting affected wood.
The close collaboration between the company, Aprofruit technicians and Rome and Caserta's C.R.A. (Centre and Research Unit for Fruit Growing) helped to tackle the emergency in a short period of time and increasing the knowledge of the bacteria by taking samples of infected material.
"At the moment, the company started producing regularly once again, reaching satisfying yields (this year, 40 tonnes/hectare are expected) especially considering that the disease is still affecting the area."
The Mariani company.
The secret of such a success is the prompt and scrupulous activation of defence operations that have been made known to the kiwi production areas in Italy.
"We must consider that kiwi bacteriosis cannot be treated like a normal disease as it is, in fact, pandemic. A procedure must therefore be followed respecting the disease cycle, the phenological phases of the plant and the characteristics of the soil. Some agronomic practices must be modified accordingly, otherwise the measures taken will not be effective."
The Mariani company. Orchards are protected by hail nets also to prevent the bacteria from spreading after a hailstorm.
The company therefore undertook to protect plants during those moments when the bacteria is most likely to spread - germination, blossoming, post-setting, after harvesting and during Winter. By being careful during pollination and the growing of fruits, the aim was to safeguard production for the year and to reduce the risk of the disease spreading in the future.
In addition, protective treatments were carried out immediately before or after weather events that favour the bacteria such as hailstorms, strong rainfalls and freezes as well as right after Winter pruning. In particular, the company tried to protect all pruning cuts, even the small ones, as Psa can easily penetrate.
Mr. Donato Mariani (left) and dr. Marco Scortichini (right).
At the same time, particular measures were taken to avoid damaging plants while tying and curving young branches. Male pollinators, which were particularly affected by bacteriosis, were substituted by more resistant clones.
Dr. Scortichini observes that, "the pruning and growing techniques were slightly modified to favour air passing through the orchard thus reducing humidity levels."
"The chemical composition of the soil was also analysed, and it resulted in it being rather acid and unbalanced. By administering products capable of increasing pH levels and balancing macro and micronutrients the ideal conditions to cultivate kiwis are slowly being reinstated," concludes the researcher.
For further info:
C.R.A.-Centro di Ricerca per la Frutticoltura
Via di Fioranello, 52
00134 Roma
Tel.: (+39) 06 79348102
Fax: (+39) 06 79340158
Marco Scortichini
Email: marco.scortichini@entecra.it
Web: www.atlasplantpathogenicbacteria.it