L Charlet Bhami, S Sam Manohar Das1. 1. Department of Zoology and Research Centre, Scott Christian College (Autonomous), Nagercoil, Tamil Nadu, India.
Abstract
BACKGROUND & OBJECTIVES: The use of low concentrations of boric acid as a potential and effective control agent for the eggs and immature stages of Aedes aegypti L. and Aedes albopictus Skuse (Diptera: Culicidae) is found to be safe and effective as compared to synthetic chemical insecticides. The study aims to determine the ovicidal concentration of boric acid, its effective concentration for oviposition attraction and the larval mortality concentration for Ae. aegypti and Ae. albopictus. METHODS: The ovicidal concentration of boric acid was determined by incubating the eggs in different concentrations of boric acid (0.1, 0.25, 0.5, 0.75 and 1%). Different dilutions of boric acid were taken in the oviposition cup and the ovicidal concentration, effective concentration for oviposition attraction and the mean survival/mortality rate of III and IV instar Ae. aegypti and Ae. albopictus larvae were determined. RESULTS: The ovicidal concentration of boric acid for 100% mortality in Aedes sp eggs is 1%. Effective concentration for the oviposition attraction is 0.5%. At 1% concentration, larvae of both the species died within 24 h. INTERPRETATION & CONCLUSION: Boric acid is less toxic compared to different pesticides, and in low concentrations, it attracts the ovipositing female Aedes sp as well as fertile males. Dilute boric acid solution is an effective ovitrap since the eggs laid by mosquitoes either die or the larvae that hatch out from them do not survive in boric acid. Boric acid kills the males that come in contact with the solution, which are attracted to the trap by the females hovering around.
BACKGROUND & OBJECTIVES: The use of low concentrations of boric acid as a potential and effective control agent for the eggs and immature stages of Aedes aegypti L. and Aedes albopictus Skuse (Diptera: Culicidae) is found to be safe and effective as compared to synthetic chemical insecticides. The study aims to determine the ovicidal concentration of boric acid, its effective concentration for oviposition attraction and the larval mortality concentration for Ae. aegypti and Ae. albopictus. METHODS: The ovicidal concentration of boric acid was determined by incubating the eggs in different concentrations of boric acid (0.1, 0.25, 0.5, 0.75 and 1%). Different dilutions of boric acid were taken in the oviposition cup and the ovicidal concentration, effective concentration for oviposition attraction and the mean survival/mortality rate of III and IV instar Ae. aegypti and Ae. albopictus larvae were determined. RESULTS: The ovicidal concentration of boric acid for 100% mortality in Aedes sp eggs is 1%. Effective concentration for the oviposition attraction is 0.5%. At 1% concentration, larvae of both the species died within 24 h. INTERPRETATION & CONCLUSION:Boric acid is less toxic compared to different pesticides, and in low concentrations, it attracts the ovipositing female Aedes sp as well as fertile males. Dilute boric acid solution is an effective ovitrap since the eggs laid by mosquitoes either die or the larvae that hatch out from them do not survive in boric acid. Boric acid kills the males that come in contact with the solution, which are attracted to the trap by the females hovering around.