A Method for Estimating Abundance of the Weevil, Hylobius warreni Wood, and Its Damage in Lodgepole Pine Stands

Abstract

A sampling technique is described for estimating the abundance of the weevil, Hylobius warreni Wood, in even-aged lodgepole pine stands. The percentage of trees currently infested is the basic measurement sought in the survey of a stand. Estimates of growth reduction (radial increment of stem, length of leader shoot) are given for young pine trees with 50% girdling damage. The relation between minimum weevil population level required to achieve 50% girdling and stand age class is described. This relation serves to establish a basis for gauging the severity of infestation.