The genus Cladosporium is imperfect filamentous fungi belonging to the class Deuteromycetes. The perfect form belongs to the class Ascomycetes (Amorphotheca, Mycosphaerella, Venturia). This genus includes about 500 species.
Their velvety or flaky colonies are generally olive-brown to dark brown and dull. The conidiophores, more or less distinct from the mycelium, are branched, straight or with sympodial growth, geniculate or not. Unicellular or multicellular conidia are produced in acropetally chains. They are ovoid, elliptical or fusiform, smooth, warty or echinulate, and often with visible insertion scars.
The Cladosporia are ubiquitous, cosmopolitan (air, soil, plants, cereals, food, etc.), and extremely common as phytopathogens especially in temperate zones. Some species are implicated in type I and III allergies and mycoses. These diseases are caused by the production of mycotoxins (cladosporin, emodin).
The Cladosporia have a significant industrial interest in the biolconversion of steroid precursors to progesterone and pregnenolone.