401 Document heading doi: 10.1016/S2222-1808(12)60087-5 襃 2012 by the Asian Pacific Journal of Tropical Disease. All rights reserved. Spatial and temporal distribution of mosquito larvicidal compounds in mangroves M Syed Ali 1 , S Ravikumar 2* , J Margaret Beula 3 1 PG Department of Biotechnology, Mohammed sathak college of Arts and Science, Sohlinganallur, Chennai, Tamil Nadu, India 2 School of Marine Sciences, Department of Oceanography and Coastal Area Studies, Alagappa University, Thondi, Tamil Nadu, India 3 Department of Chemistry, Scott Christian College (Autonomous), Nagercoil, Tamil Nadu, India Asian Pac J Trop Dis 2012; 2(5): 401-404 Asian Pacific Journal of Tropical Disease journal homepage:www.elsevier.com/locate/apjtd *Corresponding author: S Ravikumar, School of Marine Sciences, Department of Oceanography and CAS, Alagappa University, Thondi, Tamil Nadu-623409, India. Mobile: +0091-456-1243470 Fax: +0091-456-1243470 E-mail: ravibiotech201321@gmail.com Foundation Project: Supported by Ministry of Environment and Forest with grant number D.O.NO.3/2/2004 CS(M)-11.12.2006. 1. Introduction Mosquitoes are responsible for more diseases than any other groups of arthropods [1] . Interest in Aedes aegypti (Ae. aegypti) lies in the fact that it acts as a vector for an arbovirus responsible for yellow fever in Central and South America and in West Africa. This mosquito is also the vector of dengue hemorrhagic fever, which is endemic to South East Asia, the Pacific islands area, Africa and the Americas [2] . Indeed, the present recrudescence of these diseases is due to the higher number of breeding places in today’s throwaway society and to the increasing resistance of mosquitoes to current commercial insecticides. Although yellow fever has been reasonably brought under control with its vaccine, no vaccine is available for dengue. The only way of decreasing the incidence of this disease is thus the eradication of Ae. aegypti. Experience has shown that aerial toxicants for the eradication of this mosquito are not effective, since it is highly domesticated and many adults rest indoors in hidden places like closets. The only successful way of reducing mosquito densities to a level where dengue or yellow fever epidemics do not occur is by attacking the larval breeding places [3] . The ideal control method is thus the systematic treatment of their breeding places through larvicides [4] . Researchers are now looking for natural insecticides which do not have any ill effects on non-target population and are easily degradable. The search is underway to find out newer insecticides which will be effective and safe, and also easily available at low cost. Due to spiraling costs of insecticides and labour, paucity of funds and resistance developed by plasmodia or anophelines to chemicals, diseases carried by mosquitoes are back since 1980. Hence, there is a constant need for developing biologically active plant materials as larvicides, which are expected to reduce the hazards to human and other organisms by minimizing the accumulation of harmful residues in the environment. Natural products are generally preferred because of their less harmful nature to non-target ARTICLE INFO ABSTRACT Article history: Received 20 September 2012 Received in revised form 25 October 2012 Accepted 28 October 2012 Available online 28 October 2012 Keywords: Aedes aegypti Avicennia marina Insecticides Larvicidal activity Mosquito control Objective: To identify the larvicidal activity of the mangrove plant extracts. Methods: Parts (bark, root, leaf and flower) of mangrove plants, Avicennia marina (A. marina), Acanthus ilicifolius, Bruguiera cylindrica and Excoecaria agallocha (E. agallocha), were dissolved in DMSO to prepare a graded series of concentration. Batches of 25 early 4th instars larvae of Aedes aegypti (Ae. aegypti) were transferred to a 250 mL enamel bowl containing 199 mL of distilled water and 1 mL of plant extracts (0.01-0.10 mg). Each experiment was conducted with three replicates and a concurrent control group. A control group consisted of 1 mL of DMSO and 199 mL of distilled water only. After 24 h, the percentage of mortality was determined. Results: The bark extract of A. marina showed maximum larvicidal activity against the 4th instars larvae of Ae. aegypti, followed by the leaf extract of E. agallocha. The presence of flavonoids, terpinoids and sponins in the ethanolic extracts of A. marina might be responsible for the larvicidal activity. Conclusions: It is concluded from the present study that the mosquitocidal toxins of A. marina might be a prospective alternative in mosquito control programme involving mangrove biopesticides. Contents lists available at ScienceDirect