Biological Control of Blue Stain in Pulpwood: Mechanisms of Control used by Phlebiopsis gigantea

Abstract

SummaryPhlebiopsis 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 withP. giganteashortly 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 asOphiostoma piliferumandO. piceaewas greatly reduced or completely inhibited with prior inoculation byP. 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 withO. piliferum2 weeks prior to inoculation withP. giganteawere 88% colonized byO. piliferumand had 33% of the sapwood stained after 7 weeks, and 33% colonized and 18% stained after 29 weeks. Scanning electron micrographs ofP. giganteaandO. piliferumhyphae showedP. giganteaparasitizing the blue stain fungus.Phlebiopsis giganteawas shown penetrating and growing adjacent to collapsed and disintegrated blue stain hyphae.Phlebiopsis giganteaalso decolorized sapwood previously stained blue.