Anatomical changes in Willow Wood Decayed by the brown rot fungus Coriolellus malicola (Basidiomycota)

In Argentina, Salix wood is employed mainly in pulp and paper industry. In this country, the brown rotter C oriolellus malicola was found in association with willow plantations. The purpose of this work was to study the anatomical changes caused by C. malicola in willow wood in order to provide information on the effects of brown rot decay in the yield and quality of pulp. Two willow clones were employed: Salix nigra 4 and Salix babylonica x Salix alba cv I 131-25 . Two exposure times were used: 75 and 150 days. The percentages of weight loss produced by this fungus in both clones was ca. 30% at 75 days and ca. 60% at 150 days of decay. C. malicola degraded mainly fibre walls. Microscopically, the loss of cell shape, the presence of transwall fractures and the loss of birefringence were the main anatomical modifications observed. According to our observations decayed Salix wood by C. malicola seems to be inadequate for pulp industry.