General Biology and Life Cycles of Bark Weevils

Abstract

The large pine weevil, Hylobius abietis (L.) is the single most important insect pest of reforestation in northern and western Europe. The number of scientific papers published annually on this insect continues to increase in response to the need to find long-term solutions to the problems it causes. Its common name in English suggests that it is one of the larger weevils found feeding on conifers. Adults are about 8-14mm long (Eidmann 1974). The large pine weevil breeds in conifer stumps but feeds on conifer seedlings, so its reputation as a pest is greatest in countries which employ clear-cut plantation forestry. Other species of Hylobius, H. pinastri Gyll. and H. piceus De G. occur in large parts of Europe (Eidmann 1974; Langstrom 1982). The biology of H. pinastri is similar to that of H. abietis (Nordlander 1990), although H. pinastri appears to prefer moist areas dominated by spruce (Langstrom 1982; Nordlander 1990). Hylobius pinastri is moderately abundant in Scandinavia and makes up about a quarter of the weevil population (with H .abietis) in Estonia (Luik and Voolma 1989). Hylobius piceus is less common and mostly found in moist forests, almost never on clear-cuttings. It breeds in the root collar of living conifer trees and the adults are seldom observed feeding on seedlings (Eidmann 1974; A. Lindelow pers. comm.). A fourth European species, Hylobius transversovittatus (Goeze), lives in the roots of a perennial plant Lythrum salicaria, and is hence of no interest in this