Sariga, Shonima Govindan M. and Kunhi A.A.M. 2016. Evaluation of Larvicidal and Mosquitocidal Activity of Leaf Extracts of Gliricidia sepium against Culex quinquefasciatus. Abstract Book. National symposium on ‘Biosciences and Technology –Recent Developments and Future Prospects’, SIAS-Centre for Scientific Research, Safi Institute of Advanced Study, Vazhayoor, Malappuram, Kerala, p. 40.

ABSTRACT

Mosquitoes can transmit more diseases than any other group of arthropods and affect millions of people throughout the world. The major tool in mosquito control operation is the application of synthetic insecticides such as organochlorine and organophosphate compounds. Because of resistance to current insecticides and to environmental, health, and regulatory concerns, naturally occurring compounds and their derivatives are of increasing interest for the development of new insecticidal compounds against vectors of disease-causing pathogens. The objective of the study was designed to extract and purify larvicidal compounds from Gliricidia sepium, which is used as insect repellents in different regions of Kerala state. The plants were collected and powdered leaves were extracted sequentially using different solvents of increasing polarity and the extracts were screened for their larvicidal activity against 4th instar larvae of Cx.quinquifasciatus. Among the different solvent extracts acetone extract (100ppm) exhibited toxic effect with LC50 value 175.7ppm. The AC extract is then purified by column chromatography and yielded eight different compounds. All the recovered compounds were screened for their larvicidal activity and PF2, PF6 and PF8 was found to be active. Preliminary studies on the larvicidal activity of purified fractions against Cx. quinquifasciatus showed 100% mortality at a concentration of 100ppm. The phytoconstituent of the active fractions was found to be a Terpenoid. Specially designed excito repellency test chambers were used to evaluate the mosquito repellent activity of crude acetone extract. Repellency is known to play an important role in preventing the vector born diseases by reducing man vector contact. 

 

Keywords: Gliricidia sepium, Terpenoid, Larvicidal, Mosquito repellent activity