In nature, Phoma is a widespread type of mold commonly found in soil and a wide range of plants and plant materials.

It is one of the most important plant disease causing agents. In indoor environments, Phoma is common on wet/damp paints, wood, wall papers, window frames and caulking, especially in bathrooms. Species of Phoma are also commonly isolated from house dust. The common species in an indoor environment are Phoma glomerata and P. macrostoma.

Phoma species are mainly contaminants, though they may rarely cause infections in humans, particularly to individuals with a weakened immune system. While they are not known to pose an inhalation hazard to humans, any mold growing in human occupied environments should be treated as potentially hazardous.