Phellinus noxius is a fungus that causes BRR disease on trees. Belonging to the genus Phellinus, P. noxius is placed under the family of Hymenochaetaceae within the Phylum Basidiomycota. Most of the species within the genus Phellinus act as saprotrophs in nature or as weak pathogens on trees. Only very few species are pathogenic with strong virulence, and P. noxius is one of the strongest among them. It prefers acidic, hot and humid conditions. It is characterised by its brownish black fruiting bodies (which will turn black with a drop of 3-5%KOH) with no clamp connections in its vegetative hyphae. The species within Phellinus are the typical white rotters, which can release enzymes through the action of microhyphae and decompose lignin and polysaccharides such as cellulose, hemicellulose and pectic substance, resulting in wood decay. Phellinus noxius causes white simultaneous rot in which the major components of wood (i.e. cellulose, hemicellulose and lignin) degrade at approximately the same rate.