EFFECTS OF INTERCROPPING SORGHUM-COWPEA ON NATURAL ENEMIES OF THE SORGHUM SHOOT FLY, ATHERIGONA-SOCCATA (DIPTERA, MUSCIDAE), IN BURKINA-FASO

Experiments were conducted in 1990 and 1991 at Matourkou near Bobo-Dio ulasso, Burkina Faso (West Africa), to study the effect of intercroppi ng sorghum-cowpea, Sorghum bicolor L. (Moench)-Vigna urguiculata (Walp .), on the natural enemies of the sorghum shoot fly, Atherigona soccat a Rondani (Diptera: Muscidae). Sampling was done weekly, on six occasi ons starting 10 days after sowing. Natural enemies of eggs were Tricho grammatoidea simmondsi Nagaraja (Hymenoptera: Trichogrammatoidae), Tap inoma sp. (Hymenoptera: Formicidae), Fusarium sp. and a bacterium, Cor ynebacterium sp. Other insect species included a thysanopteran (Phlaeo thripidae, Haplothripinae) and Dicrodiphosis sp. (Diptera: Cecidomyiid ae) which were also associated with the sorghum shoot fly eggs. No sig nificant differences were observed between the pure sorghum and the in tercropped sorghum-cowpea with respect to T. simmondsi parasitism. Lar val parasitoids were Neotrichoporoides nyemitawus Rohwer (Hymenoptera: Eulophidae), (6 to 17.50% of parasitism), Bracon sp. (Hymenoptera: Br aconidae), and Hockeria sp. (Hymenoptera: Chalcididae). One pupal para sitoid was recorded, Alysia sp. (Hymenoptera: Braconidae). Significant differences were observed in the percentage of larval parasitism in 1 990 and in 1991 between the pure sorghum and intercropped sorghum-cowp ea. There was about two-fold and 1.4-fold increased larval parasitism in intercropped sorghum-cowpea in 1990 and 1991 respectively. Morisita 's index of similarity (0.94 in 1990, 0.98 in 1991, between pure sorgh um and intercropped sorghum-cowpea, 0.98 between 1990 and 1991), indic ated that the parasitoid species composition was independent of both t he cropping system and the year.