Invasive Species Compendium

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Abstract

Western balsam bark beetle, Dryocoetes confusus Swaine, flight periodicity in northern Utah.

Abstract

The flight periodicity of western balsam bark beetle (Dryocoetes confusus), a serious pest of drought-stressed Abies lasiocarpa, was studied during the summer months of 1992-94 in Big Cottonwood Canyon, Utah. Contents of baited funnel traps were tallied by species up to 3 times weekly. Two main periods of flight activity were observed each year. The first and, generally, largest occurred in early summer soon after flight was initiated for the season. A second period was observed in late summer, generally August. Timing of the 2 periods was influenced by unusually warm or cool weather in each study year. The first period had more males than females while the second period had a majority of females. Except during periods of cool or wet weather, western balsam bark beetles were active, at least at minimum levels, from June until September.