none Laboratory and field observations were made in Ilocos Norte, Philippines from 1983 to 1985 and in 1988 to study the behaviour and efficiency of the parasitoid, Microgaster manilae (Ashmead) against the common cutworm, Spodoptera litura (F.), on tobacco. M. manilae is a predominant solitary, internal larval parasitoid of the common cutworm on tobacco, and hereby recorded for the first time. The mating and parasitization behaviour are described. Field-collected or laboratory-bred S. litura larvae exposed to M. manilae in the field showed 50% parasitization.