Dj. Morrison et Db. Redfern, LONG-TERM DEVELOPMENT OF HETEROBASIDION-ANNOSUM IN BASIDIOSPORE-INFECTED SITKA SPRUCE STUMPS, Plant Pathology, 43(5), 1994, pp. 897-906
The extent of colonization by Heterobasidion annosum was measured in 1
989 in Sitka spruce stumps that had been inoculated with basidiospores
in 1981 and assessed for infection in 1983. Only stumps that had infe
ction in the sapwood in 1983 contained the fungus in 1989. There was a
significant positive correlation between the sapwood area colonized i
n 1983 and the total area colonized in 1989. Between 1983 and 1989, H.
annosum spread within the body of stumps and into most primary roots.
There were significant correlations between the stump area colonized
in 1983 and 1989 and the percentage of stump and root volume colonized
in 1989. Roots of 26 excavated stumps were in contact with an average
of two roots on each of two living trees. Fourteen roots on eight liv
ing trees became infected, and H. annosum spread proximally an average
of 126 cm into trees. We believe that this is the first report of the
transfer of H. annosum from spruce stumps inoculated with basidiospor
es to adjacent live trees.