Plant Extracts as Repellents against Adults of Tribolium castaneum, Rhyzopertha dominica and Sitophilus oryzae

The repellency of ten plant extracts was tested against three stored product insects, Tribolium castaneum, Sitophilus oryzae and Rhyzopertha dominica using the filter paper bioassay technique. Results showed that only few tested plants had repellent activity against T. castaneum and R. dominica but moderate to high repellent activity against S. oryzae by all the plants tested. Adults of S. oryzae repelled faster, followed by T. castaneum and R. dominica. At the longest time intervals, filter paper treated with Anagillis arvensis and Hibiscus rosa sinensis were the most effective repellents to adults of T. castaneum and S. oryzae (up to 60% after 24 h) and Lapsana communis for R. dominica (up to 50% after 24 h). The lowest repellent activity exhibited by Calotropis procera and L. communis (up to 15% after 24h) against T. castaneum. H. rosa sinensis and Azadirachta indica (upto 15% after 24h) against R. dominica and Chenopodium album against S. oryzae (upto 17.5% after 24 h).