Identification and Pathogenicity of Biscogniauxia and Sordaria Species Isolated from Olive Trees

A field investigation of olive trees in Istria, Croatia, revealed branch dieback and cracked bark. Samples of diseased branches were collected from eight different locations and analysed. Additionally, meteorological data from two locations were analysed to determine if there was a connection between climatic changes and the appearance of pathogens in the region. Pathogenicity tests were conducted on olive seedlings. This study provides a description of Biscogniauxia and Sordaria species' morphology and elucidates their phylogeny based on the internal transcribed spacer (ITS), beta-tubulin (TUB2) and translation elongation factor 1-alpha (TEF1- alpha) regions. This research represents the first documented occurrence of Biscogniauxia mediterranea causing charcoal disease in olive trees in Croatia. Additionally, it is the first report of Biscogniauxia nummularia (Bull.) Kuntze and Sordaria fimicola causing diseases in olive trees anywhere in the world. Furthermore, this study marks one of the initial forays into molecular investigations of these species isolated from olive trees. Considering the potential threat posed by the inherent aggressiveness of Biscogniauxia species, further research is deemed necessary to curb the development of charcoal disease.