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 laboratory and field trials by a colorless strain of O. piliferum, Cartapip-97. This strain lacks melaninlike compounds responsible for the discoloration of sapwood. Inoculation of logs with Cartapip in the laboratory 2 wk before challenging with other fungi resulted in 58-68% colonization for Cartapip in isolated wood chips, while O. piliferum, O. piceae, O. minus, Phanerochaete gigantea, or Trichoderma harzianum colonized 0, 0, 0, 0, and 61%, respectively. Inoculation of logs with Cartapip 4 wk before other fungi resulted in similar trends with strong inhibition of blue-stain fungi. Simultaneous inoculation of logs with Cartapip and other fungi resulted in decreased colonization by both Cartapip and Ophiostoma species. When blue-stain fungi, P. gigantea or T. harzianum were inoculated 2 wk before Cartapip, colonization for these fungi ranged from 19 to 64% in cultured wood chips, whereas Cartapip ranged from 0 to 45% among the different treatments. Inoculation of O. piliferum and O. piceae prior to Cartapip resulted in inhibition of Cartapip. Two field trials demonstrated the exclusion of blue-stain fungi 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 colonized only 0-8%. In contrast, blue-stain fungi colonized 63% of the cultured wood chips in untreated control logs during the first field trial, and 29 and 71% for untreated control and antitranspirant treatments, respectively, during the second field trial. Results from both laboratory and field trials show the effectiveness of Cartapip for protecting freshly cut wood from blue-stain fungi.