Pellicularia filamentosa is a type of fungus that belongs to the family Atheliaceae. This fungus tends to form a dense white mycelium which becomes matted and felty over time. Synonyms for Pellicularia filamentosa include Athelia rolfsii, Sclerotium rolfsii, Corticium rolfsii, and Teliosporium rolfsii. It is a parasitic fungus that attacks several plants such as legumes, onions, and tomatoes. The fungus is known to cause root rot in plants that results in stunted growth, wilting, and yellowing of leaves. Despite its negative effects on plants, the species is useful in biocontrol and has been used in the production of commercial enzymes.