Local population structure of white pine weevil (Pissodes strobi [Peck]) in interior and Sitka spruce stands in British Columbia

White pine weevil is a pest of interior and Sitka spruce species in British Columbia. It is native to eastern Canada, and migrated to the west. To date, control of the weevil has been ineffective even with the combined use of several control methods. Current research has focused on breeding resistant trees for use in plantations to overcome attack from Pissodes strobi. Knowledge of the weevil genetic structure on a small-scale stand level is extremely important in developing strategies that decrease the possible development of tolerance in P. strobi populations to resistant trees. To understand the population structure of P. strobi 15 microsatellite markers were used to investigate local population structure. Genetic structure of local weevil populations differed over stand age in both interior and Sitka spruce plantations. The younger and older plots had more single populations associated with individual trees than did middle aged plots. Middle-aged plots had increased beetle movement regardless of the number of weevil larvae per leader, increased number of females ovipositing per tree and less weevil genetic differentiation between trees. Understanding reproductive dynamics of P. strobi will help develop strategies for planting resistant trees to decrease the development of insect tolerance and further our knowledge of the possible co-evolutionary dynamics of this system.Forestry, Faculty ofGraduat