An examination of genetic variation and disease spread in Inonotus tomentosus in the sub-boreal spruce zone of British Columbia

Inonotus tomentosus (Fr) Teng. is a fungal pathogen of commercially valuable tree species in British Columbia and one of the most important biotic disturbance agents in sub-boreal and boreal forests in Canada. This study investigated the population variation in spruce stands infected with Tomentosus Root Rot (TRR) to determine whether infection is due to spread by root contact, by basidiospores, or a combination of the two and if forest management affects the mode of disease spread. There is high genotypic variation within all populations in addition to moderate levels of gene diversity and significant deviation from Hardy-Weinberg Equilibrium. Results indicate frequent recombination (i.e. and subsequent spore dispersal is the most likely cause the variation observed in these sites. There was no difference in the population structure of this pathogen between unmanaged stands and plantations.