BIOLOGICAL-CONTROL OF BLUE-STAIN FUNGI IN WOOD

Biological control of blue-stain fungi, such as Ophiostoma spp., that are detrimental to the wood products industry, was demonstrated in lab oratory and field trials by a colorless strain of O. piliferum, Cartap ip-97. This strain lacks melaninlike compounds responsible for the dis coloration of sapwood. Inoculation of logs with Cartapip in the labora tory 2 wk before challenging with other fungi resulted in 58-68% colon ization for Cartapip in isolated wood chips, while O. piliferum, O. pi ceae, O. minus, Phanerochaete gigantea, or Trichoderma harzianum colon ized 0, 0, 0, 0, and 61%, respectively. Inoculation of logs with Carta pip 4 wk before other fungi resulted in similar trends with strong inh ibition of blue-stain fungi. Simultaneous inoculation of logs with Car tapip and other fungi resulted in decreased colonization by both Carta pip and Ophiostoma species. When blue-stain fungi, P. gigantea or T. h arzianum were inoculated 2 wk before Cartapip, colonization for these fungi ranged from 19 to 64% in cultured wood chips, whereas Cartapip r anged from 0 to 45% among the different treatments. Inoculation of O. piliferum and O. piceae prior to Cartapip resulted in inhibition of Ca rtapip. Two field trials demonstrated the exclusion of blue-stain fung i with prior colonization of the sapwood by Cartapip. Four weeks after inoculation of logs in the field, 92-100% of cultured wood chips were colonized by Cartapip in both trials, while blue-stain fungi colonize d only 0-8%. In contrast, blue-stain fungi colonized 63% of the cultur ed wood chips in untreated control logs during the first field trial, and 29 and 71% for untreated control and antitranspirant treatments, r espectively, during the second field trial. Results from both laborato ry and field trials show the effectiveness of Cartapip for protecting freshly cut wood from blue-stain fungi.