Fungi associated with Dendroctonus rufipennis and Polygraphus rufipennis, and white spruce inoculation tests

Fungi were isolated from Dendroctonus rufipennis and Polygraphus rufipennis and from discolored wood around their galleries in white spruce, Picea gla uca. Leptographium abietinum was the most commonly isolated blue stain fung us for both beetle species. Inoculation of five species of fungi commonly i solated from both beetles on white spruce seedlings resulted in 71% of the seedlings colonized by L. abietinum being killed quickly but no mortality o f seedlings inoculated with other fungi. Leptographium abietinum may help b eetles to overcome the defense of weakened trees during mass attack.