Comparison of Two Treatment Regimes for Managing Western Balsam Bark Beetle


  • Lorraine E. Maclauchlan Forest Entomologist, MFLNRORD – Kamloops
  • Julie E. Brooks Forest Health consultant



Dryocoetes confuses, felled trap tree, pheromone baiting


The efficacy of pheromone-baited, standing subalpine fir Abies lasiocarpa (Hook) Nutt. and felled green trap trees was tested in southern British Columbia as potential manage- ment techniques for containing western balsam bark beetle Dryocoetes confusus Swaine populations prior to logging. In the year treatments were deployed, standing trees in close proximity to baited trees had significantly higher levels of current attack than those near felled trap trees or in control blocks. The control blocks had the lowest level of current at- tack. Diameters of attacked trees were significantly greater than unattacked trees in all treatments. Naturally attacked, standing subalpine fir had high levels of occupation (number of nuptial galleries) along the full length of the bole. Baited trees had similar levels of occupancy up to six metres in height. Felled green trees had lower occupancy than the baited or naturally attacked trees. Although baited trees concentrated attack into a discrete area, they did not artificially trigger an outbreak or further population expansion in the year following treatment. Felled trap trees appeared less attractive to western balsam bark beetle than natural, susceptible, standing subalpine fir; they are more difficult to de- ploy and therefore not recommended as a means of containing western balsam bark beetle prior to logging.

Author Biography

Julie E. Brooks, Forest Health consultant

Lorraine has been with the Regional Forest Entomologist with the Ministry of Forests, Lands and Natural Resource Operations and Rural Development, based in Kamloops, since 1987. She has taught Forest Entomology at Thompson Rivers University from 1995 to 2016. Lorriane received her BSc from the University of Victoria (1980) and Masters of Pest Management (1985) and Ph.D. (1992) from Simon Fraser University, specializing in forest pest management and pests of young stands. She is a Registered Forest Professional, Registered Professional Biologist and has been active in many professional organizations throughout her career. Lorraine’s operational and research endeavors are broad, including work on the effects of changing climate on dynamics, impacts and management of forest insect pests.






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