Alternate Hosts of the Elm Spanworm1 Egg Parasitoid, Ooencyrtus ennomophagus2,3

Abstract

Ooencyrtus ennomophagus Yoshimoto, an important parasitoid of the elm spanworm, Ennomos subsignarius (Hiibner), was recovered from field-collected eggs of the eastern tent caterpillar, Malacosoma americanum (F.), but the incidence of parasitism was low. Only eggs collected before embryonation occurred produced O. ennomophagus adults. In the laboratory, O. ennomophagus parasitized unembryonated eggs of the eastern tent caterpillar which had the spumaline removed. O. ennomophagus isolated from field-collected eastern tent caterpillar eggs readily attacked unembryonated eggs of the elm spanworm. O. ennomophagus also developed in unembryonated eggs of the fall cankerworm, Alsophila pometaria (Harris), but rarely developed in embryonated eggs of the eastern tent caterpillar and not at all in unembryonated or embryonated eggs of the gypsy moth, Porthetria dispar (L.). Neither O. clisiocampae (Ashmead) nor O. kuwanai (Howard) parasitized eggs of the elm spanworm.