Chemical compositions and insecticidal efficacies of four aromatic essential oils on rice weevil Sitophilus oryzae L

Abstract

Plant essential oils contained secondary metabolite chemicals showing toxicities on stored grain insects. The main aims of this study was to evaluate the insecticidal efficacies and chemical compositions of essential oil from C. flexuosus, C. winterianus, C. martini, and P. cablin against Sitophilus oryzae (L.). The GC-MS analysis results showed that, the essential oils of four aromatic plants are rich in citral, neral, geranyl acetate, geraniol, citronellal, geraniol, citronellol, photocitral B, azulene and α-guaiene respectively. The essential oils of C. flexuosus with LC50 values are 44.5 and 26.1 μl/L air after 24 and 48 h exposure which was found to be most potent fumigant than C. winterianus followed by C. martini and P. cablin respectively. Further, in contact toxicity, C. martini oil being the most effective against adults of S. oryzae with LC50 values of 2.6 and 1.8 μl/cm2 after 24 and 48 h exposure respectively, whereas moderate toxicity was observed in S. oryzae from the essential oils of C. winterianus and P. cablin. These results suggested that the essential oils extracted from C. flexuosus, C. winterianus, C. martini, and P. cablin can be used as in the management of S. oryzae in order to decrease the harmful effects and risk of synthetic insecticides on human beings.