Trichoderma Species from Douglas-Fir Stumps and Roots Infested with Phellinus Weirii in the Western Cascade Mountains of Oregon

ABSTRACT

Six species of Trichoderma were isolated from Douglas-fir stumps and roots infested with Phellinus weirii. Trichoderma viride and T. polysporum were the most common species. Trichoderma spp. were isolated more frequently from stem portions of stumps harvested 11 years earlier than from those harvested one year earlier. Colonization by these and other fungi was less extensive in roots than in stems. Although the overall frequency of isolation of Trichoderma spp. was low (70 of 5970 isolations), their greater association with wood decayed by P. weirii, as compared with undecayed wood, may have implications in the control of laminated root rot.

Key Words:

• Trichoderma
• Phellinus weirii
• biological control
• antagonism
• Douglas-fir