Since the 1990s, severe decline and mortality events have affected the Fraxinus species widespread in Europe. The disease observed for the first time on common ash (Fraxinus excelsior) in Poland, quickly spread to over 20 states of the old continent causing serious damage from both an ecological and economic point of view. In Italy, the first symptoms were observed in Friuli Venezia Giulia in 2009, and subsequently in other regions of Northern and Central Italy. Since the mid-2000s, the disease was attributed to the ascomycete fungus Hymenoschyphus fraxineus, however, recent studies have made it possible to expand knowledge on the causes of the decline of the ash tree and to associate other pathogens with the disease, and in particular, two aggressive pathogens belonging to the Botryosphaeriaceae family, Diplodia fraxini and D. subglobosa and various species of the Phytophthora genus. Despite this, some etiological aspects of the disease are still not clear and in particular, the temporal dynamics with which the various pathogens determine the appearance of symptoms. Therefore, given the alarming spread of the disease in Veneto, as part of this degree thesis, research was started aimed at broadening the information on the topic, and in particular on the phytopathogenic species involved in the symptoms of necrosis and collar rot. Specifically, the investigations were conducted in an ash grove in Cadore (Belluno, Veneto). Within the investigation site, two plants with the typical symptoms of the disease were identified at random and samples were taken in the collar and root area. Laboratory analyzes made it possible to isolate and characterize 203 colonies belonging to 24 species of fungi and oomycetes. The results obtained confirmed the etiological complexity of the disease and allowed us to clarify the temporal and spatial dynamics of attacks by Diplodia fraxini, Phytophthora plurivora and Armillaria cepistipes. Overall, the results obtained highlight a network of ecological interactions between the three phytopathogenic species.
A partire dagli anni ’90, estesi fenomeni di deperimento e moria hanno interessato con sempre maggiore frequenza tutte le specie del genere Fraxinus diffuse in Europa. La malattia osservata per la prima volta su frassino maggiore (Fraxinus excelsior) in Polonia, si diffuse rapidamente in oltre 20 stati del vecchio continente causando gravi danni dal punto di vista sia ecologico che economico. In Italia, i primi sintomi furono osservati in Friuli Venezia Giulia nel 2009, e successivamente nelle altre regioni del Nord e del Centro Italia. A partire dalla metà degli anni 2000, la malattia fu attribuita al fungo ascomicete Hymenoschyphus fraxineus, tuttavia, studi recenti hanno permesso di ampliare le conoscenze sulle cause del deperimento del frassino e di associare alla malattia anche altre specie, ed in particolare, due patogeni aggressivi afferenti alla famiglia delle Botryosphaeriaceae, la Diplodia fraxini e la D. subglobosa e varie specie del genere Phytophthora. Nonostante ciò, alcuni aspetti eziologici della malattia ancora non sono chiari ed in particolare, la dinamica temporale con cui i vari patogeni determinano la comparsa dei sintomi. Pertanto, vista l’allarmante diffusione della malattia in Veneto, nell’ambito di questa tesi di laurea è stata avviata una ricerca volta ad ampliare le informazioni sul tema, ed in particolare sulle specie fitopatogene coinvolte nei sintomi di necrosi e marciume del colletto. Nello specifico le indagini sono state condotte in un frassineto del Cadore (Belluno, Veneto). All’interno del sito di indagine sono state individuate at random due piante con i sintomi tipici della malattia e prelevati campioni di fusto nella zona del colletto e di radici. Le analisi di laboratorio hanno consentito di isolare in purezza e caratterizzare 203 colonie appartenenti a 24 specie di funghi ed oomiceti. I risultati ottenuti hanno confermato la complessità eziologica della malattia e consentito di chiarire la dinamica temporale e spaziale degli attacchi di Diplodia fraxini, Phytophthora plurivora e Armillaria cepistipes. Nel complesso i risultati ottenuti evidenziano una fitta rete di interazioni ecologiche tra le tre specie fitopatogene.
Nuove acquisizioni sull’eziologia del deperimento del frassino maggiore in Italia
ZUIN, GIACOMO
2022/2023
Abstract
Since the 1990s, severe decline and mortality events have affected the Fraxinus species widespread in Europe. The disease observed for the first time on common ash (Fraxinus excelsior) in Poland, quickly spread to over 20 states of the old continent causing serious damage from both an ecological and economic point of view. In Italy, the first symptoms were observed in Friuli Venezia Giulia in 2009, and subsequently in other regions of Northern and Central Italy. Since the mid-2000s, the disease was attributed to the ascomycete fungus Hymenoschyphus fraxineus, however, recent studies have made it possible to expand knowledge on the causes of the decline of the ash tree and to associate other pathogens with the disease, and in particular, two aggressive pathogens belonging to the Botryosphaeriaceae family, Diplodia fraxini and D. subglobosa and various species of the Phytophthora genus. Despite this, some etiological aspects of the disease are still not clear and in particular, the temporal dynamics with which the various pathogens determine the appearance of symptoms. Therefore, given the alarming spread of the disease in Veneto, as part of this degree thesis, research was started aimed at broadening the information on the topic, and in particular on the phytopathogenic species involved in the symptoms of necrosis and collar rot. Specifically, the investigations were conducted in an ash grove in Cadore (Belluno, Veneto). Within the investigation site, two plants with the typical symptoms of the disease were identified at random and samples were taken in the collar and root area. Laboratory analyzes made it possible to isolate and characterize 203 colonies belonging to 24 species of fungi and oomycetes. The results obtained confirmed the etiological complexity of the disease and allowed us to clarify the temporal and spatial dynamics of attacks by Diplodia fraxini, Phytophthora plurivora and Armillaria cepistipes. Overall, the results obtained highlight a network of ecological interactions between the three phytopathogenic species.File | Dimensione | Formato | |
---|---|---|---|
Zuin Giacomo.pdf
accesso riservato
Dimensione
3.98 MB
Formato
Adobe PDF
|
3.98 MB | Adobe PDF |
The text of this website © Università degli studi di Padova. Full Text are published under a non-exclusive license. Metadata are under a CC0 License
https://hdl.handle.net/20.500.12608/59303