Poria vallantii (Fibroporia vallantii, Antrodia vallantii)- Brown Rot Fungus

poria valantii- wet rot

Fibroporia vaillantii is widely distributed in Europe and it is recognised as the  most frequent fungus in British mines.  Antrodia (Fibroporia) vaillantii, also known as mine fungus - white pore wood-decaying fungus;which can occur on timberin humid conditions. The fungus causes brown rot of pine wood, in which cellulose and hemicellulose are broken down, leading to brown discoloration and shrinkage of wood.

The fungus grows on wood from coniferous trees, such as pine wood, under damp conditions, with a wood moisture content of 40 to 50 percent. In humid atmospheres, the white cotton-like mycelium can grow on wood surfaces and cross inert materials, similar to the true dry rot fungus Serpula lacrymans. In newly grown mycelium, fine drops of clear liquid may be present. The optimal temperature for growth is 28 °C;it will grow at temperatures between 3 and 36 °C. The fruiting body is an irregular white plate with a thickness of 2 to 12mm.

Fibroporia vaillantii differs from the cellar fungi and Serpula lacrymans by its mycelia, strands, and fruit bodies. Fibroporia vaillantii forms  a well-developed white and cottony surface mycelium without inhibition colours, which, thus, can be confused with the young mycelium of Serpula lacrymans. The mycelium may spread ice flower-like over the substrate, that of Serpula lacrymans is converted with ageing into silvery-grey skins, and that of the cellar fungi is dominated by fine black strands. White (A. vaillantii), to string-thick, smooth and flexible strands develop within the mycelium and rarely grow over non-woody substrates and through porous brickwork.

wet rot by poria valantii

Fibroporia vaillantii, are resistant to copper mainly due to the excretion of oxalic acid and subsequent formation of Cu-oxalate. Fibroporia vaillantii decreased the life-time of timber impregnated with chromated copper arsenate and borate, respectively. Chromium, which plays a role in the fixation reactions of the elements in wood, and arsenate as well as borate were solubilized by oxalic acid and subsequently washed out by rain.