|Can Baser, K.|
Submitted to: Pest Management Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/12/2005
Publication Date: 8/1/2005
Citation: Sampson, B.J., Tabanca, N., Kirimer, N., Demirci, B., Can Baser, K.H., Khan, I.A., Spiers, J.M., Wedge, D.E. 2005. Insecticidal activity of 23 essential oils and their major compounds against adult lipaphis pseudobrassicae (davis) (aphididae: homoptera). Pest Management Science. 61: 1122-1128. Interpretive Summary: Essential oils from 23 plant species were evaluated for insecticidal activity against turnip aphids. Major compounds from essential oils were identified using a variety of analytical instruments. Mortality rates were established for the essential oils and their major compounds using laboratory aphid bioassays. These studies showed that plant species such as Bifora, Pimpinell, and Satureja could rapidly kill aphids at very low concentrations. Essential oils from a variety of herbs and medicinal plants may have useful agrochemical applications as horticultural oils, plant protectants, and fumigants. Pimpinella spp. appears to have significant promise for agrochemical development.
Technical Abstract: Essential oils from 23 species of plants comprising 14 genera and 4 plant families were extracted by Clevenger-type water distillation. Major compounds of these essential oils were identified with gas chromatography-mass spectroscopy. Insecticidal activity of the oils and their major components was evaluated using small cohorts of turnip aphids (Lipaphis pseudobrassicae (Davis) subjected to serial-time mortality bioassays. We examined the mortality rates of only asexually reproducing foundresses (i.e. fundatrices and apterous virginoparae) because sizeable aphid populations on cruciferous (=Brassicaceae) hosts largely originate from these wingless, parthenogenic females. Oil mixtures and isolated compounds from Pimpinella isaurica were topically applied to aphid females in randomized blocks at concentrations of 0.0, 1.0, 2.5, 5.0, and 10.0 mg ml(-1). Penetration of the insect cuticle by the essential oil mixtures was enhanced by an emulsifying agent, dimethyl sulfoxide (DMSO). Overall aphid mortality and LC50 values were calculated after 10, 30, 60 min and 24 h of exposure to the test materials. Analyses show that aliphatic aldehydes, phenols, monocyclic terpenes and their structural analogs found in the oils of Bifora and Satureja can rapidly kill aphids at very low concentrations 0.3 - 1.0 mg ml(-1). Pimpinella oils also contained novel bioactive phenylpropanoids that functioned synergistically to kill adult L. pseudobrassicae. Other unidentified components of Pimpinella oils were also responsible for insecticidal activity.