This mould feeds primarily upon the honeydew that is excreted by insects and the liquid exuded by leaves. Domestically, it is found on bathroom walls, where it grows from damp surfaces. It requires this free water for growth. As small, slowly-evaporating puddles or areas of water are left near baths, the fungus will quickly germinate and spread. The fungus can grow on walls and ceilings where condensation has gathered water. The colonies of Cladosporium cladosporiodes spread quickly and look like small brown patches. This fungus is a common harbinger of allergic reactions, which usually appear as a rash on the skin.