**1. Introduction**

Endophytic fungi are plant-associated microorganisms that colonize the internal tissues of the host without inducing disease symptoms [1]. They represent a poorly understood endosymbiotic group of microbes that ought to be attentively considered by the scientific community, so as to provide comprehensive knowledge regarding their beneficial role and the actual extent of their interactions with plants.

A basic issue hindering studies on the ecological role of these microorganisms is represented by the reported endophytic occurrence of fungal pathogens. In fact, besides the cases where latency is a conspicuous phase of the disease cycle, there are more and more records of renowned pathogens found within asymptomatic hosts, for which an explanation is not immediately available [2–4]. Increasing and organizing the current knowledge on conditions associated with the occurrence of these ambiguous species is useful for a more conclusive assessment of their functions and impact on crops. This present paper offers an overview of a fungus which is mainly studied as a pathogen of tropical crops [4–6] but that is potentially able to spread as an endophytic associate of plants in the temperate zone.
