EARLY STAGES OF BLUE-STAIN FUNGUS INVASION OF LODGEPOLE PINE SAPWOOD FOLLOWING MOUNTAIN PINE-BEETLE ATTACK

Invasion of lodgepole pine sapwood by blue-stain fungi was followed for 7 weeks after infestation by the mountain pine beetle, Dendroctonus ponderosae. During this period all sapwood was heavily stained blue and blue-stain fungi were always isolated close to the front of visible occlusion. Ophiostoma clavigerum and Ophiostoma montium were commonly isolated, both of which are known to be carried in the mycangia of the mountain pine beetle. Ophiostoma montium was most frequently isolated, but when both fungi were present O. clavigerum was always at the leading edge of fungal penetration. On average O. montium trailed 7.3 mm behind O. clavigerum. Other microorganisms were seldom isolated.