Control of the Pine Root Collar Weevil, Hylobius radicis1

Abstract

The pine root collar weevil (Hylobius radicis Buchanan) has become increasingly important in recent years in stands of planted pines in southern Ontario, southeastern Manitoba, and the northeastern United States. Scots pine is most seriously affected, but native hard pines growing in association with Scots pine are sometimes damaged. The weevil breeds in the root collar of healthy pines, killing more than 90% of the trees in some plantations. Ten insecticides were tested on the weevil from 1954 to 1956. Ethylene dichloride was effective in killing the larvae, but failed to prevent re infestation, Lindane and dieldrin applied as water emulsions directly to the ground around the base of the trees effectively controlled the insect for at least 4 years.