The experiments were carried out in the laboratory at 26 ±2°C and 60 ±5% RN to evaluate the bioactivity of certain plant extracts against three insect species infesting stored maize grains. i.e. the rice weevil Sitophilus oryzae (L.), the red flour beetle Tribolium castaneum (Herbst) and the lesser grain borer Rhizopertha dominica (F). The plant extracts were the acetone and petroleum ether of Poinciana seeds Delonix regia, Cinnamon strip bark Cinnamomum zeylanicum, Colves flowering buds Syzygium aromatcum, Mustrad seeds Brassica alba and Radish seeds Raphanus sativus). The results, revealed that, the adults of T. castaneum were the least susceptible to the various tested plant extracts followed by R. dominica and S. oryzae adults, which were the most sensitive. It was also apparent that, the reduction in F1 progeny of T castaneum was much higher than mortality at all tested concentrations of the plant extracts. Results showed also that the repellency effect of the tested plant extracts varied from one plant to another. Data revealed that S. oryzae adults showed the highest repellency values with the various plant extracts at various intervals in comparison to the two other insect species (T castaneum and R. dominica). While the R. dominica- adults were the lowest response repellency values.