G. Tacconi¹, L. Tosi², L. Nari³, L. Berra³, D. Spadaro⁴, S. Prencipe⁴, M. Rosati⁴, S. Saro⁵, A. Giacopini⁶, C. Morone⁷, M. Giannini⁸, S. Serra⁸, G. Cipriani⁹, M. Martini⁹, M. Scortichini¹⁰, Bardi¹¹, F. Savian¹², A. Lamontanara¹, V. Michelotti¹, L. Orru¹, P. Ermacora⁹.

1 CREA, Centro Genomica e Bioinformatica –Fiorenzuola d’Arda (Piacenza) Italy.
2 Agrea Centro Studi – S. Giovanni Lupatoto (Verona) Italy.
3 Fondazione Agrion – Manta (Cuneo) Italy.
4 DISAFA e AGROINNOVA, Università degli Studi di Torino Largo Paolo Braccini, 2 10095 Grugliasco (Torino) Italy.
5 ERSA – Servizio Fitosanitario e Chimico, Ricerca, Sperimentazione e Assistenza Tecnica (Udine) Italy.
6 Direttore Mercato Ortofrutticolo di Sommacampagna e Sona (Verona) Italy.
7 Settore Fitosanitario e Servizi Tecnico Scientifici – Regione Piemonte (Torino). Italy.
8 Veneto Agricoltura -Porto Tolle (Rovigo) Italy.
9 Università degli Studi di Udine (Udine) Italy.
10 CREA Centro di Ricerca Olivicoltura, Frutticoltura e Agrumicoltura (Roma) Italy.
11 CREA, Centro Ingegneria e Trasformazioni Agroalimentari (Torino) Italy.
12 CREA Agricoltura Ambiente, (Bologna) Italy.

Abstract
Since 2012, kiwifruit vine decline (KVD) became the most serious disease of kiwifruit in Italy: over 25% of the cultivated area are affected. “The leaves wither and face down as if to escape the sun; the roots darken and rot. Then the leaves fall (…). Within one or two years, the plant dries up and dies. There is no cure.” (The Guardian, 2020). These sentences well describe the syndrome: KVD is related to climate change, soil conditions and soil-borne diseases. Abiotic (aerial and underground conditions), biotic (fungi, oomycetes, bacteria) stresses and plant response (physiological and genetic aspects) were studied in the main kiwifruit area where KVD appears in Northern and Central Italy. Exceptional rainfall, high temperature for many days during the summer were recorded in the last years in different region, moreover water excess during the irrigations was consider the main causes of KVD, even if the same irrigation practices were successfully adopted by the farmer in the last 30 years ago. Different pathogens were isolated in many areas since 2014 until now, but a common agent was not identified. Neither of these factors taken alone appears to be able to lead to KVD and their combination that must be studied. The control of predisposing factors, such as water excess (by irrigation or rain) with the adoption of raised-beds and the optimization of irrigation, help to reduce KVD in the first years but does not solve the problem over five years in two field trials set up in two regions, Veneto and Piedmont, where KVD appear on raised-beds 2-3 years later than in plane field surface. Environmental monitoring (soil and aerial), plant physiology and metagenomic analysis used together will help to define the role of each factors. Moreover, germplasm evaluation for the identification of tolerant rootstock is ongoing.

Keyword: kiwifruit vine decline; water management, raised-beds, pathogens, rootstock, climate change.