Indagini sulla capacità di colonizzazione di alcuni funghi agenti di carie sulle principali specie arboree in ambito urbano

Trees play a pivotal role in the built environment as they provide ecological, biological and social benefits. However, they are susceptible to various forms of stresses which can affect their vitality and cause premature senescence, which in turn may make them more vulnerable fungal pathogens. In the cities, the major factors causing or fovouring tree failures decays caused by wood destroying fungi, resulting in serious risks to people and goods. This thesis was designed to evaluate through in vitro and in controlled conditions experiments the ability of colonization of wood of some of the most common wood decay agents on the major urban tree species. Such a goal was achieved by performing in vitro growth experiments and by inoculating branches of plane trees, , linden and horse chestnut trees, with the following fungal species: Fomitiporia punctata (P. Karst) Murrill, Ganoderma adspersum (Schulzer) Donk, G. resinaceum Boud., Laetiporus sulphurous (Bull.) Murrill, Kretzschmaria deusta (Hoffm.) P.M.D. Martin, Perenniporia fraxinea (Bull.) Ryvarden and Schizophyllum commune Fr. Fungi were identified based on the macromorphology of fruiting bodies and were isolated in pure culture, for subsequent in vitro growth tests. The three fastest growing isolates for each fungal species were inoculated in the branches. After a 7-month incubation period, it was possible to investigate the level of colonization of each fungal isolate within each section of the branches, using where necessary a PCR-based molecular analysis with taxon-specific primers. The plane wood was colonized by every fungal species which displayed colonization ability of 93-100%, the linden of 0-31%, and the horse chestnut wood of 2-27%. Overal, S. commune was the species with the highest potential ability for host colonization, regardless of the species, followed by L. sulphurous, K. deusta, P.fraxinea, F. punctata, G. resinaceum and G. adspersum. In conclusion, and from a practical perspective, this study highlight the relatively high vulnerability of plane trees as compared to linden and horse chestnut wood decay fungi, suggesting this species would require particular attention during tree hazard assessment campaigns.