Mosquito larvicidal activity of Hyptis suaveolens (L.) Poit (Lamiaceae) aerial extracts against the filarial vector Culex quinquefasciatus Say (Diptera: Culicidae)
Murugesan Sakthivadivel, Palani Gunasekaran, Murugesan Sivakumar, Subramanian Arivoli, Rajasingh Raveen and Samuel Tennyson
Mosquito-borne diseases have intruded the globe since immemorial time. The present scenario for commanding the mosquitoes is aimed at application of target and stage-specific, cost-effective and biodegradable phytoproducts. Plant extracts are safer for non-target organisms including man. Plant based formulations would be more feasible environmental products with proven potential as insecticide. Therefore, in the present study the larvicidal activity of crude petroleum ether, chloroform and acetone aerial extracts of Hyptis suaveolens against the filarial vector, Culex quinquefasciatus was studied. Standard WHO protocols with minor modifications was adopted for the larvicidal bioassay. Larvicidal activity was evaluatedat concentrations of 62.5, 125, 250, 500 and 1000 mg/L. Larval mortality was observed for 24 and 48 hours. Amongst the solvent extracts tested, acetone exhibited highest larvicidal activity and LC50 values was 485.61 followed by petroleum ether and chloroform extract which were 493.44 and 625.97 mg/L after 24 hours. In the case of 48 hours, petroleum ether extract (LC50 298.76 mg/L) was found to exhibit highest larvicidal activity followed by acetone (LC50 344.03 mg/L) and chloroform (LC50 429.50 mg/L). Further investigations are needed to explore the larvicidal activity of acetone and petroleum ether aerial extract of this plant against a wide range of mosquito species and also the active ingredient(s) of the extract responsible for larvicidal activity should be identified.