PARASITOIDS OF THE AFRICAN STEM BORER, BUSSEOLA-FUSCA (LEPIDOPTERA, NOCTUIDAE), IN SOUTH-AFRICA

Eighteen parasitoids were recorded from the African stem borer, Busseo la fusca (Fuller), on maize and grain sorghum, in Delmas and Cedara, S outh Africa. In Delmas, larval parasitism on both crops fluctuated bel ow 20% with occasional peaks of 40-60%. In Cedara, larval parasitoids were active throughout the season with peaks of 75% and 60% parasitism during January and March-April, respectively on the ratoon crop, and 20% in May on the crop. Pupal parasitism peaked in Cedara at 100% duri ng February-March, and at 80% during November, when parasitoids attack ed pupae that formed after B. fusca larvae had emerged from diapause a nd pupated. In Delmas activity by pupal parasitoids was negligible. Th e egg parasitoids, Telenomus busseolae Gahan (Hymenoptera: Scelionidae ) and Trichogrammatoidea lutea Girault (Hymenoptera: Trichogrammatidae ), were rare. The larval parasitoid, Cotesia sesamiae (Cameron) (Hymen optera: Braconidae), was active throughout the season and was by far t he most abundant, emerging from about 90% of parasitized larvae. Its c ocoons were often attacked by Aphanogmus fijiensis (Ferriere) (Hymenop tera: Ceraphronidae). Second in abundance among the larval parasitoids was Bracon sesamiae Cameron (Braconidae) whose cocoons were attacked in turn by Eurytoma braconidis Ferriere (Hymenoptera: Eurytomidae). Eu rytoma braconidis was reared also from cocoons of Euvipio sp. and Alei odes sp. (both Braconidae). All other larval parasitoids were rare. Pr ocerochasmias nigromaculatus (Cameron) (Hymenoptera: Ichneumonidae) wa s the most abundant pupal parasitoid. Trichogrammatoidea lutea, Glypta panteles maculitarsis (Cameron) (Braconidae) and Odontepyris transvaal ensis (De Buysson) (Hymenoptera: Bethylidae) have not been recorded be fore from B. fusca. Some considerations and proposals for introduction s of parasitoids into South Africa against B. fusca are discussed.