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

Female Cotesia flavipes Cameron and Cotesia sesamiae (Cameron) were at tracted to odors in a Y-tube olfactometer from uninfested maize (Zea m ays L.), sorghum [Sorghum bicolor (L.)], and napier grass (Pennisetum purpureum Schumach). In dual choice tests, Cotesia flavipes showed a p reference for maize over sorghum, while maize and napier grass were eq ually attractive. in contrast, Cotesia sesamiae preferred volatiles fr om sorghum and napier grass over those from maize. The two parasitoids were significantly more attracted to maize infested with the stembore rs, Chile partellus (Swinhoe), Chilo orichalcociliellus Strand, Sesami a calamistis Hampson, and Busseola fusca (Fuller), than uninfested mai ze. In dual choice tests, Cotesia flavipes and Cotesia sesamiae were u nable to discriminate between odors from plants infested by the differ ent species of stemborers.