Among the 20 geometrid species recovered from annual surveys in coniferous forests in the Swiss Alps, three species, Epirrita autumnata (Borkhausen), Agriopis aurantiaria Hübner, and Poecilopsis isabellae Harrison, were identified as sources for parasitoids that might be suitable as candidates for introduction to Newfoundland to control the eastern hemlock looper, Lambdina fiscellaria fiscellaria (Guenée). Four univoltine Hymenoptera were identified as candidates: Dusona contumax (Forster) (Ichneumonidae) from A. aurantiaria, Dusona sp. from P. isabellae, Aleiodes cf. gastritor (Thunberg) (Braconidae) from E. autumnata, and Aleiodes. sp. from P. isabellae. The candidate parasitoids were confined with their native hosts in the laboratory and observations made to gather basic biological information and define protocols for screening.
Small numbers of these parasitoids were shipped to Newfoundland and screened in the laboratory against hemlock looper larvae. Although attacks by D. contumax, Dusona sp., and A. cf. gastritor were observed, parasitoid development did not occur. All parasitoid eggs recovered from the hemlock looper larvae attacked were encapsulated. Dusona contumax, Dusona sp. from P. isabellae, A. cf. gastritor, and Aleoides sp. from P. isabellae are not recommended for introduction against the eastern hemlock looper.