Host Location and Acceptance byCotesia flavipesCameron andC. sesamiae(Cameron) (Hymenoptera: Braconidae), Parasitoids of African Gramineous Stemborers: Role of Frass and Other Host Cues

Naive females ofCotesia flavipesCameron andCotesia sesamiae(Cameron) were attracted, in a T-tube olfactometer, to volatile kairomones from frass produced byChilo partellus(Swinhoe),Chilo orichalcociliellusStrand,Sesamia calamistisHampson, andBusseola fusca(Fuller) fed on maize (Zea maysL.), sorghum [Sorghum bicolor(L.)], and napier grass (Pennisetum purpureumSchumach). In dual-choice tests,C. flavipesandC. sesamiaewere generally unable to discriminate between volatiles from frass produced by any of the four different stemborer species fed on maize stalk. When larvae ofC. partellusandS. calamistiswere washed in distilled water, their acceptance by both parasitoid species was reduced