Insecticidal A ctivity and C omposition of E ssential O il of Ostericum sieboldii (Apiaceae) A gainst Sitophilus zeamais and Tribolium castaneum

 In our screening program for new agrochemicals from local wild plants, essential oil of Ostericum sieboldii flowering aerial parts was found to possess strong insecticidal activity against the red flour beetle, Tribolium castaneum and maize weevil, Sitophilus zeamais. The e ssential oil of O. sieboldii w as obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC-MS). A total of 42 components of the essential oil were identified. The principal compounds in the essential oil O. sieboldii aerial parts were myristicin ( 30.31 %), α- terpineol (9. 9 2%), α- c adinol ( 7 . 2 9 % ) and β- farnesene ( 6.26 %) and l inalool (5.94%) . The essential oil possessed strong contact toxicity against S. zeamais and T. castaneum adults with LD 50 value s of 1 3.82 µg/adult and 8.47 µg/adult , respectively . The essential oil also showed fumigant toxicity against S . zeamais and T. castaneum adults with LC 50 value s of 27.39 mg/ L air and 20.92 mg/ L air , respectively .