Chemical composition and insecticidal effect of methanol extract of Capparis spinosa L. fruits on Tribolium confusum Jacquelin du Val, 1863 and Sitophilus oryzae (L., 1763) adults

Abstract

Tribolium confusum and Sitophilus oryzae are stored product pests found worldwide. Environmental damages, human health issues and the emergence of resistance are driving scientists to seek alternatives to synthetic insecticides for its control. Under this scenario, plant secondary metabolites are being increasingly studied as bioinsecticides because they are renewable, natural, biodegradable, non-persistent in the environment and safe to non-target organism and humans. In this study, the chemical composition and lethal effects of methanol extract of Capparis spinosa fruits on Tribolium confusum and Sitophilus oryzae adults were studied. The LC₅₀ of extract on T. confusum and S. oryzae in contact method were 14.7 and 10.5 mg cm^-2, respectively, whereas in the dip method, the LC₅₀ value determined 41.3 and 34.3 mg ml^-1 for T. confusum and S. oryzae, respectively. The most important identified compounds were the thymol (22.5 %), methyl sulfonyl heptyl isothiocyanate (13.3 %), butyl isothiocyanate (8.1 %), γ-terpinene (6.2%) and iso propyl isothiocyanate (5.8 %). The results confirmed the potential of the C. spinosa extract in controlling stored-product insects.