ORIGINAL PAPER Essential oil composition and larvicidal activity of Saussurea lappa roots against the mosquito Aedes albopictus (Diptera: Culicidae) Zhi Long Liu & Qing He & Sha Sha Chu & Cheng Fang Wang & Shu Shan Du & Zhi Wei Deng Received: 7 November 2011 /Accepted: 24 November 2011 /Published online: 14 December 2011 # Springer-Verlag 2011 Abstract In recent years, uses of environment friendly and biodegradable natural insecticides of plant origin have re- ceived renewed attention as agents for vector control. The aim of this research was to determine larvicidal activity of the essential oil derived from roots of Saussurea lappa (Compositae) and the isolated constituents against the larvae of the Culicidae mosquito Aedes albopictus. Essential oil of S. lappa roots was obtained by hydrodistillation and ana- lyzed by gas chromatography (GC) and GC-mass spectrom- etry (MS). A total of 39 components of the essential oil of S. lappa roots were identified. The essential oil has higher con- tent of (79.80%) of sesquiterpenoids than monoterpenoids (13.25%). The principal compounds in S. lappa essential oil were dehydrocostus lactone (46.75%), costunolide (9.26%), 8-cedren-13-ol (5.06%), and α-curcumene (4.33%). Based on bioactivity-directed fractionation, dehydrocostus lactone and costunolide were isolated from S. lappa essential oil. Dehy- drocostus lactone and costunolide exhibited strong larvicidal activity against A. albopictus with LC 50 values of 2.34 and 3.26 μg/ml, respectively, while the essential oil had an LC 50 value of 12.41 μg/ml. The result indicated that the essential oil of S. lappa and the two isolated constituents have potential for use in control of A. albopictus larvae and could be useful in search of newer, safer and more effective natural compounds as larvicides. Introduction Mosquitoes transmit a variety of diseases, such as yellow fever, dengue fever, malaria, several forms of encephalitis and filariasis. The Asian tiger mosquito (Aedes albopictus Skuse) and the yellow fever mosquito (A. aegypti L.) are two main species of mosquito responsible for dengue fever and malaria in China. The control of mosquito larvae world- wide depends primarily on continued applications of orga- nophosphates such as temephos and fenthion, and insect growth regulators such as diflubenzuron and methoprene (Yang et al. 2002). Although effective, repeated use of these controlling agents has fostered several environmental and health concerns, including disruption of natural biological control systems, outbreaks of other insect species, wide- spread development of resistance and undesirable effects on non-target organisms (Isman 2006). These problems have highlighted the need for new strategies for mosquito larva control. From this viewpoint, botanical pesticides are promising since they are effective, environmentally friendly, easily biodegradable, and often inexpensive. Plant essential oils have been suggested as alternative sources for insect control, because some are selective, biodegrade to nontoxic products, and have few effects on non-target organisms and the environment (Isman 2006). They are generally recog- nized as safe by the US Food and Drug Administration. It is acknowledged that many essential oils and compounds de- rived from various essential oils can exert toxic activity against mosquito species (Araujo et al. 2003; Amer and Mehlhorn 2006; Bhat and Kempraj 2009; Gu et al. 2009; Pavela et al. 2009; Conti et al. 2010; Koliopoulos et al. Z. L. Liu (*) : S. S. Chu Department of Entomology, China Agricultural University, Haidian District, Beijing 100193, China e-mail: zhilongliu@cau.edu.cn Q. He : Z. W. Deng Analytic and Testing Center, Beijing Normal University, Haidian District, Beijing 100875, China C. F. Wang : S. S. Du State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Haidian District, Beijing 100875, China Parasitol Res (2012) 110:2125–2130 DOI 10.1007/s00436-011-2738-0