Mayetiola piceae (spruce gall midge) is a species of gall-forming flies in the Cecidomyiidae family. An outbreak of spruce gall midge occurred in northern Alberta and adjacent areas in the Northwest Territories in 1992 (Brandt 2000). The infestation was widespread in white spruce stands, with 84% of surveyed sites infested and twig mortality as high as 81% among current-year shoots. Earlier, Rose and Lindquist (1985) had noted that severe injury to spruce is unusual, and had been recorded only from a number of locations in Yukon Territory. Levels of damage in the 1992 outbreak decreased at most sites in 1994, and by spring 1995 the outbreak had collapsed. About 15 million ha were affected at the peak. Other outbreaks have occurred in Yukon Territory in 1968 and 1969 (Tripp et al. 1970), in