Fumigant toxicity and lethal activity of essential oil from Haplophyllum tuberculatum to Tribolium castaneum and Sitophilus oryzae

In this study, fumigant activity of Haplophyllum tuberculatum (Forssk.) A. Juss (Rutaceae) essential oil was assessed against Tribolium castaneum Herbst and Sitophilus oryzae L. . The experiment was conducted at 27±1 C, 60± 5 RH% in dark condition. Dry leaves and flowers were subjected to hydrodistulation using a modified Clevenger-type apparatus to obtain essential oil. The fumigant toxicity was studied against one to seven days old adult of T. castaneum and S. oryzae with four concentration at several exposure times (3, 6, 9, 12 and 24h.). Results showed that H. tuberculatum oil was shown to be highly effective on adults of T. castaneum and S. oryzae. The mortality of 1-7 days old adults was found to be increased significantly as its concentration and time were increased. Analysis showed that S. oryzae (LC50= 14.9 μl.L-1) was more susceptible to H. tuberculatum than T. castaneum (LC50= 23.1 μl.L-1). The finding indicated the efficiency of H. tuberculatum oil to manage store product pests such as T. castaneum and S. oryzae.