Infection of lodgepole pine and white spruce by Alberta isolates of Armillaria

Abstract

Two experiments were conducted to test the hypothesis that white spruce (Piceaglauca (Moench) Voss) is less liable than lodgepole pine (Pinuscontorta Dougl. var. latifolia Engelm.) to be attacked by Alberta isolates of Armillaria. In the first experiment, 27 two-year-old containerized pine and spruce were inoculated with each of 19 different isolates representing North American biological species (NABS) I and V, the Foothills variant of NABS I, and A. mellea s.str. In the second experiment, 10 containerized seedlings of both species were inoculated with eight different isolates of NABS I and transferred to 2-L pots 2 months later. Inoculum survived better in association with spruce seedlings than with pine. In both experiments, spruce seedlings were more frequently infected than pine seedlings, and more likely to die when infected, although this difference was significant only in the first experiment. Favoring or planting spruce on sites with Armillaria root rot, therefore, cannot be recommended in Alberta.