Insecticidal Properties of Three Jatropha Species Against Stored Grain Pests

Laboratory experiments were conducted to study the effect of botanical seed oil, root and leaf extracts of Jatropha nana (JN), J. gossypifolia (JGO) and J. glandulifera (JGL). Four concentrations (20, 15, 10 and 5 mg/ml) of each dry extract were obtained by dissolving the dry extract in 1 ml of acetone. The stored grain pests, Corcyra cephalonica and Tribolium castaneum were used for investigations. Jatropha species which exhibited 50% (LC₅₀) and 95% lethal concentration (LC₉₅) values against Corcyra larvae and Tribolium adults were recorded. The activity of oils against Corcyra were found in range of JGO < JGL < JN. Leaf pet ether extract activity observed were JN < JGL < JGO and leaf methanol extract were JGL < JN < JGO. While in case of root pet extract these were JN < JGL and JGO does not show any activity upto 20 mg concentration. Root methanol extract showed JGL < JN < JGO. The activity of oil against Tribolium adults showed that JGL <JN < JGO, while ether extracts were found in range of JGO> JN> JGL and methanol extract JN < JGL < JGO. Phytochemical study showed almost all primary and secondary metabolites are found in leaf and root extracts. The pet ether extract of root showed that JGO < JN < JGL and methanol extracts were in range of JN < JGO < JGL. TLC/HPTLC study showed presence of α-sitosterol in all extracts. J. gossypifolia oil was found to be most toxic to the C. cephalonica and T. castaneum with LC₅₀ values of 2.17 and 1.08 mg, respectively.