PARASITISM IN SUSTAINED AND COLLAPSING POPULATIONS OF THE JACK PINE BUDWORM, CHORISTONEURA PINUS PINUS FREE. (LEPIDOPTERA: TORTRICIDAE), IN ONTARIO, 1985–1987

Abstract

AbstractSixteen species of parasitoids were found attacking outbreak and collapsing populations of the jack pine budworm, Choristoneura pinus pinus Free. (Lepidoptera: Tortricidae), in several plots in northeastern and northwestern Ontario. The patterns of parasitism were similar among widely separated plots with only a few species consistently dominating the parasitoid fauna. The greatest difference in the pattern of parasitism was between sustained and collapsing infestations. Collapsing populations of jack pine bud-worm were associated with relatively high levels of parasitism by Meteorus trachynotus Vier. (Hymenoptera: Braconidae) and Lypha setifacies (West.) (Diptera: Tachinidae) which attacked the late larval stages of the budworm. The results are discussed in comparison with other jack pine budworm studies and with spruce budworm population studies.