LIFE-CYCLE AND MORTALITY OF PISSODES TERMINALIS (COLEOPTERA, CURCULIONIDAE) IN LODGEPOLE FINE

The seasonal life history and mortality of the lodgepole terminal weev il, Pissodes terminalis Hopping (Coleoptera: Curculionidae), were inve stigated in young lodgepole pine, Pinus contorta Douglas var, latifoli a Engelmann (Pinaceae), at three sites in west-central Alberta. Flight was monitored with traps. Development and mortality of all stages wer e investigated by dissecting infested leaders biweekly from late sprin g to early fall. Two years were required for P. terminalis to complete its life cycle, and generations overlapped. Overwintered adults emerg ed from the duff and commenced flight in late May, with a peak in mid- June. Eggs were present from mid-June to late July. There were four la rval instars. The first two instars fed only in the phloem. Third and fourth larval instars eventually entered the pith to continue feeding, overwinter, and complete development the following spring. The new ge neration of adults emerged between mid-July and early August, fed on n ew shoots for several weeks, and overwintered in the duff. Adults have an obligatory diapause and did not reproduce until after winter. Four th larval instars suffered the highest mortality. The major attributab le cause of mortality was resinosis among eggs and young larvae and co ld temperatures during the winter among mature larvae. Pathogens cause d little mortality. Six species of parasitoids were collected.