The bioassay experiments were conducted using adult granary weevil beetles (Sitophilus granarius L.), larvae of confused flour beetle (Tribolium confusum Duv.) and larvae of khapra beetle (Trogoderma granarium Ev.). Insects were grown on a wheat grain or whole-wheat meal diet in laboratory colonies, which were maintained at 26 ± 1 °C and 60 ± 5% relative humidity.