Evaluation of western balsam bark beetle flight periodicity on the Bighorn National Forest, Wyoming

This evaluation reports the flight periodicity of western balsam bark beetle (Dryocoetes confusus Swaine) in the Bighorn Mountains of north-centeral Wyoming. Traps baited with lures were used to determine the periods of flight activity over a five-year period. A consistent pattern of flight initiation and peaks in flight activity was found for western balsam bark bettle. Similar to previous studies in other geographic locations there were two main periods of flight activity. However, flight initiation and the first and larger peak of flight activity occurred later in the season (mid-July) compared with northern Utah and Idaho. The second and smaller peak of flight activity occurred in late August. In the 2000 season, males dominated trap catches during the first 2 wweeks and were female biased the rest of the year. In addition, trap catches of western balsam bark beetle were compared by lure (1999, 2000, 2001) and trap type (2000). No significant differences were detected between lure, trap, or their interaction on the number of beetles trapped during 2000; however, the most beetles were caught in the panel trap/3-component lure combination. The potential for using pheromone lures and tree baits for managing western balsam bark beetle is discussed.