Colletotrichum scovillei and Prospective Biocontrol Agents Isolated from Asymptomatic Olive Trees

Olive anthracnose is a major disease worldwide; although once chiefly attributed to Colletotrichum acutatum, it is now clear that the predominant pathogen varies among regions. In this study, we identified Colletotrichum scovillei for the first time as a latent pathogen in olive fruits from groves in the Peloponnese, Greece, expanding the known diversity of Colletotrichum species associated with olive anthracnose. To better understand the ecological context of this finding, we examined the role of endophytic microorganisms in olive tissues and their interactions with phytopathogens. Endophytic fungi isolated from asymptomatic ripe olive fruits and leaves were characterized for phylogeny and potential pathogenicity, while competitive interactions between Colletotrichum species and other endophytes were assessed to identify potential biological control agents. In parallel, meteorological variability among sampling sites was analyzed to explore possible links with pathogen distribution. Our results indicate that naturally occurring endophytes sharing the Colletotrichum niche can suppress the necrotrophic phase of Colletotrichum spp., supporting the potential of such endophytes as sustainable tools for disease management. We detected C. scovillei in asymptomatic olives in one sampling year and confirmed its virulence via inoculation assays. This temporally limited yet virulent occurrence, alongside the activity of resident endophytes, supports an integrated, ecology-informed approach to anthracnose management.