Effect of common salt on laboratory reared immature stages of Aedes aegypti (L)

Abstract

To observe the effect of common salt (NaCl) on immature stages of laboratory reared Aedes aegypti (L). A laboratory colony of Aedes aegypti mosquitoes of Rajahmundry strain was established in the laboratory of National Institute for Communicable Disease (NICD), Rajahmundry unit at (26 ± 2) °C with relative humidity of (70 ± 10)%. 1.00%, 1.25% and 1.50% solutions of common salt (NaCl) were selected to observe the susceptibility status of immature stages of Aedes aegypti in laboratory. Fifty percent larvae of Aedes aegypti died within 19, 31 and 48 hours when exposed to 1.50%, 1.25% and 1.00% common salt solution, respectively. Ninety percent of the larvae died within 29, 57 and 108 hours when exposed to the same salt solutions, respectively. Very high pupal mortality was observed varying from 81.8% to 40.0%. Formation of pupae was found inversely proportional in the presence of concentration of common salt in breeding water. With easy availability, less toxicity and long lasting nature, common salt may be applied in unused containers, especially in junkyards where surveillance mechanism is poor along with other conventional vector control methods in order to control breeding of Aedes aegypti, the vector of dengue/dengue hemorrhagic fever and chikungunya.