Evaluation of the Efficacy of Some Plant Oil Extracts in the Management of Tribolium castaneum (Herbst)

Four-way olfactometer was used to evaluate Laboratory repellency activities of Azadirachta indica, Jatropha curcas and Dennitia tripetala oil extracts on Tribolium castaneum at 10µl of each oil. Each arm of the olfactometer served as treatment arm with the 3 arms accommodating the 3 test substances, respectively and the 4th arm as control. Various concentrations (1, 2 and 3% V/V) of the essential oils were evaluated for fumigant and contact toxicity against T. castaneum at 8, 16 and 24 hours durations. The results obtained showed that T. castaneum spent significantly (p<0.05) more time (min) in the control arm than the 3 arms accommodating the essential oils. Similarly, significantly (p<0.05) more number of entries were made by the insect into the control arm compared with the test arms. The application of the essential oils significantly (p<0.05) caused higher mortality at 8, 16 and 24hrs than the control for both fumigant and contact tests. The mortality of the T. castaneum increased with increase in the concentration of the essential oils. The 3% concentrations of the oil extracts significantly caused the highest mortality, 67.23±8.72, 69.22± 18.74 and 79.55±9.29% by A. indica, D. tripetala and J. curcas, respectively after 24 hours application in fumigant test. The result also indicated that the contact application of A. indica, D. tripetala and J. curcas at 3% concentrations resulted in 63.07±6.55, 70.10±2.51 and 67.4±4.06% mortality of T. castaneum, respectively. The results suggest that the oil extracts from A. indica, J. curcas and D. tripetala can be used for effective management of T. castaneum infesting stored products.