The use of household bleach to control Aedes aegypti.

We evaluated the lethal effects of household bleach (5.25% sodium hypochlorite; NaOCI) on immature Aedes aegypti in tap water, with and without food, and in field-collected automobile tires. A sublethal dose was employed as a disinfectant in tires to control immatures through the destruction of microorganisms that constitute the main food items of mosquito larvae. The concentration of bleach that was required to kill all immatures was higher in the presence of larval food and older immatures. Lethal (100%) concentrations in the presence of food were 16 ppm for 1st instars, 64 ppm for 2nd instars, and 250 ppm for 3rd and 4th instars. A single treatment with 250 ppm of bleach per tire (2 tablespoons per 5 liters of water) killed the larvae, but pupae started to appear 12-17 days later. Total pupal production in 2 months decreased from 118 +/- 26 pupae/tire (mean +/- SE) in the controls without bleach to 66 +/- 5 pupae/tire in treated tires. A single treatment with 250 ppm followed by weekly applications of sublethal doses (50 ppm; a teaspoon) significantly reduced pupal production (2 +/- 1 pupae/tire in 2 months). We recommend that whenever a container that produces mosquitoes cannot be eliminated, it would be better to clean it before applying bleach. The combined action of cleaning and bleach is expected to reduce available larval food, reduce the amount of NaOCl for treating the container, and make it less attractive for future mosquito oviposition.