GC-MS Analysis of the Essential Oil and Insecticidal Activity of Teucrium quadrifarium Buch.-Ham. (Lamiaceae) Aerial Parts against Liposcelis bostrychophila

In our screening program for new agrochemicals from wild plants and Chinese medicinal herbs, Teucrium quadrifarium aerial parts at flowering stage was found to possess strong insecticidal activity against booklice (Liposcelis bostrychophila). Water-distilled essential oil from T. quadrifarium aerial parts was analyzed by gas chromatography-mass spectrometry (GC-MS). Fourty-seven components comprising 97.2 % of the total oil were identified and the main components of the essential oil were germacrene D (8.8 %), linalool (8.2 %), camphene (7.8 %), β-caryophyllene (7.3 %), β-cadinene (6.8 %), 1,8-cineole (6.5 %), 4-terpineol (5.8 %), and α-terpineol (5.1 %). The essential oil of T. quadrifarium possessed contact toxicity against L. bostrychophila with a LC50 value of 95.1 μg/cm2. The oil also showed fumigant toxicity against L. bostrychophila with a LC50 value of 222.0 μg/l. These findings suggested that the essential oil of T. quadrifarium aerial parts has potential to be developed as new natural insecticides for the control of grain storage insects.