Volatile infochemicals used in host and host habitat location by Cotesia flavipes Cameron and Cotesia sesamiae (Cameron) (Hymenoptera: Braconidae), larval parasitoids of stemborers on graminae.
Females of Cotesia flavipes and C. sesamiae were attracted to odours in a Y-tube olfactometer from uninfested maize, sorghum and napier grass (Pennisetum purpureum). In dual choice tests, C. flavipes showed a preference for maize over sorghum, while maize and napier grass were equally attractive. In contrast, C. sesamiae preferred volatiles from sorghum and napier grass over those from maize. The 2 parasitoids were significantly more attracted to maize infested with Chilo partellus, C. orichalcociliellus, Sesamia calamistis and Busseola fusca than uninfested maize. In dual choice tests, Cotesia flavipes and C. sesamiae were unable to discriminate between odours from plants infested by the different species of stem borers.