Wind tunnel and Y-tube olfactometer studies are useful for demonstrating the responsiveness of male moths to sex pheromones. However, in the cereal stem borer, Busseola fusca (Fuller) (Lepidoptera: Noctuidae), wind tunnel bioassays yielded poor results when the behavioural responses of females to plant odours were tested. We demonstrated that for B. fusca females, the Y-tube olfactometer was better suited for measuring the attractiveness of plant odours, compared with the wind tunnel. In particular, we showed B. fusca preference for odours of a host over a non-host plant species using this apparatus. Behavioural responses for B. fusca after host finding are also discussed.