Studies were conducted on the host searching behavior of the larval parasitoid Cotesia sesamiae (Cameron) (Hymenoptera: Braconidae) and the pupal parasitoid Dentichasmias busseolae Heinrich (Hymenoptera: Ichneumonidae), both of which attack lepidopteran (Crambidae, Noctuidae) cereal stemborers. The behavior of D. busseolae was observed in a diversified habitat that consisted of stemborer host plants (maize, Zea mays L. and sorghum, Sorghum bicolor (L). Moench (Poaceae)) and a non-host plant (molasses grass, Melinis minutiflora Beauv. (Poaceae)), while C. sesamiae was observed separately on host plants and molasses grass. In previous olfactometer studies, C. sesamiae was attracted to molasses grass volatiles while D. busseolae was repelled. The aim of the present study was to investigate the influence of molasses grass on close-range foraging behavior of the parasitoids in an arena that included infested and uninfested host plants. Dentichasmias busseolae strongly discriminated between host and non-host plants, with female wasps spending most of the time on infested host plants and least time on molasses grass. Likewise, C. sesamiae spent more time on uninfested and infested host plants than it did on molasses grass in single choice bioassays. While on infested plants, the wasps spent more time foraging on the stem, the site of damage, than on other areas of the plant. Overall, the results indicate that presence of the non-host plant does not hinder close range foraging activities of either parasitoid. Crambidae (Pyralidae) : Host Cotesia sesamiae (Braconidae) : Parasite Dentichasmias busseolae (Ichneumonidae) : Parasite Sensory reception; Nutrition; Diet; Parasites diseases and disorders; Parasites; Insect parasites; Hosts; Insect hosts Cotesia sesamiae; Dentichasmias busseolae; Chemoreception; Lepidopteran hosts; Close range host searching behaviour; effects of non host plants; Crambidae Crambidae; Food plants; Hymenopteran parasites; Parasitoid close range host searching behaviour; effects of non host plants; Cotesia & Dentichasmias none