Expansion of Ash Dieback towards the scattered Fraxinus excelsior range of the Italian peninsula

Abstract Hymenoscyphus fraxineus, causal agent of Ash Dieback, has posed a threat to Fraxinus excelsior (common ash) in Europe since the 1990s. In south-western Europe, optimal climatic conditions for H. fraxineus become scattered and host density decreases, reducing disease spread rates . To date, Dieback not been reported from southern most central Italy, where native F. is present as small fragmented populations. This study examines expansion into it considers consequences further local with regards loss genetic resource. Symptomatic were sampled sixteen sites northern Italy during 2020. Specimens analyzed culturomics quantitative PCR approach. A bibliographic search floristic reports was conducted creation detailed range map. The combined use both techniques confirmed presence all plants symptomatic. These new records represent limit current known distribution this pathogen together Montenegro, Europe. characterization suggests that across realistic scenario. presents just European proveniences , but species whole, should lead warm climate adapted material, which may increasingly valuable under change.