Larvicidal Activity of Artemisia nilagirica (Clarke) Pamp. and Ocimum sanctum L : a Preliminary Study

Objective: Aim of this work was to study the larvicidal activity of Artemisia nilagirica (Clarke) Pamp. and Ocimum sanctum Linn. against dengue, malaria, and filariasis transmitting mosquito larvae. Methods: The larvicidal activity of essential oil, chloroform, petroleum ether, and methanolic extracts of A. nilagirica and O. sanctum were tested against three different mosquito larvae viz., Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus. Late third instar or early fourth instar larvae were selected for the screening. These extracts and essential oil were used for determining the larvicidal activity by using WHO method for evaluation of new larvicidal agent. Results: The result suggests larvicidal activity by essential oil, petroleum ether and chloroform extract of both the plants against all three selected mosquito species, while methanolic extract was found to be inactive up to 300 ppm. Among the essential oil and extracts of A. nilagirica and O. sanctum, essential oil of O. sanctum was found to be the most potent larvicide against C. quinquefasciatus and A. aegypti larvae, while A. nilagirica essential oil was more potent larvicide against A. stephensi larvae. Conclusion: The results suggest the use of the plants in insect control as an alternative method for minimizing the noxious effects of some pesticide compounds on the environment. Thus the essential oil of O. sanctum and A. nilagirica may deliver promising, more selective and biodegradable larvicidal agents.