Phlebiopsis gigantea, a white-rot fungus currently being tested in biological processing applications for
the pulp and paper industry, was shown to effectively inhibit blue stain fungi in both laboratory and field
trials. Inoculation of logs with P. gigantea shortly after cutting resulted in up to 86% colonization of
logs in the laboratory and 100% in field studies. Colonization of logs by blue stain fungi such as Ophiostoma
piliferum and O. piceae was greatly reduced or completely inhibited with prior inoculation by P.
gigantea. In field studies, blue stain fungi colonized up to 53% of the sapwood and stained as much as
31% of the sapwood in non-inoculated control logs in contrast to 4% colonization and 2% stain in treated
logs. Logs inoculated with O. piliferum 2 weeks prior to inoculation with P. gigantea were 88% colonized
by O. piliferum and had 33% of the sapwood stained after 7 weeks, and 33% colonized and 18%
stained after 29 weeks. Scanning electron micrographs of P. gigantea and O. piliferum hyphae showed
P. gigantea parasitizing the blue stain fungus. Phlebiopsis gigantea was shown penetrating and growing
adjacent to collapsed and disintegrated blue stain hyphae. Phlebiopsis gigantea also decolorized sapwood
previously stained blue.