ORIGINAL PAPER Larvicidal efficacy of the Citrus limetta peel extracts against Indian strains of Anopheles stephensi Liston and Aedes aegypti L. Sarita Kumar & Radhika Warikoo & Monika Mishra & Anubha Seth & Naim Wahab Received: 14 December 2011 / Accepted: 23 December 2011 / Published online: 10 January 2012 # Springer-Verlag 2012 Abstract The extracts from the peels of Citrus limetta were prepared using hexane and petroleum ether as the solvents. The larvicidal potential of each extract was assessed against dengue fever vector, Aedes aegypti, and malarial vector, Anopheles stephensi, by evaluating the toxicity effects on early fourth instars. Both the extracts were found effective against both the species. The bioassay with hexane extracts resulted in LC 50 values of 132.45 and 96.15 ppm against A. stephensi and A. aegypti, respectively; while the petroleum ether extracts from the C. limetta peels showed LC 50 values of 244.59 and 145.50 ppm, respectively. It revealed that the hexane extracts possessed 1.9-fold more larvicidal potential against A. stephensi and 1.5-fold more efficacy against A. aegypti as compared to the extracts obtained using petro- leum ether as solvent. The data further revealed that the extracts were 1.4–1.7 times more effective against A. aegypti as compared to A. stephensi. The qualitative phyto- chemical study of the extracts showed the presence of ter- penoids and flavonoids as the common phytochemical constituents in the extracts suggesting their possible role in the toxicity. Other constituents tested were not detected except alkaloids which were found to be present only in the petroleum ether extract. Further studies are needed to isolate and identify the active principles involved, their mode of action, formulated preparations for enhancing po- tency and stability, toxicity, and effects on non-target organ- isms and the environment. This could help in formulating efficient strategies for mosquito control. Introduction The importance of mosquitoes as significant disease vectors transmitting diseases like malaria, filariasis, Japanese en- cephalitis, and dengue is well reported (Becker et al. 2003). Moreover, their potential to feed on more than one individual, during a single gonotrophic cycle is causing spread of diseases at larger scale (Mackenzie et al. 2004). Aedes aegypti, the primary carrier for viruses that cause dengue fever, dengue haemorrhagic fever, chikungunya fe- ver, and yellow fever is widespread over large areas of the tropics and subtropics (Service 1983; Yang et al. 2009). According to WHO (2009) about two-fifths of the world’ s population are now at risk of dengue, and the only way to prevent dengue virus transmission is to combat the disease- carrying mosquitoes. In India, a total of 28,292 cases and 110 deaths were reported because of dengue in 2010 (Na- tional Vector Borne Disease Control Programme 2011a). Malaria is one of the serious afflictions and the main causes of infant and young child mortality. More than 300 million people suffer throughout the world annually (WHO 2009). Every year, approximately 300–500 million new infections and 1–3 million deaths result from malaria world- wide (Muturi et al. 2008; Ali and Vijayan 2009). In India, 1.3 million cases of malaria and 767 deaths were reported in 2010 (National Vector Borne Disease Control Programme 2011b). Anopheles stephensi (Liston) is a major vector in India as well as in some of the West Asian countries directly responsible for about 40–50% of the annual malarial inci- dence (Rajkumar and Jabanesan 2007). The approach to combat these diseases largely relies on interruption of the disease transmission cycle by either tar- geting the mosquito larvae at breeding sites through spray- ing of stagnant water or by killing/repelling the adult mosquitoes using insecticides (Corbel et al. 2004; Joseph S. Kumar (*) : R. Warikoo : M. Mishra : A. Seth : N. Wahab Department of Zoology, Acharya Narendra Dev College (University of Delhi), Govindpuri, New Delhi 110019, India e-mail: sarita.sanjay90@gmail.com Parasitol Res (2012) 111:173–178 DOI 10.1007/s00436-011-2814-5