Insecticidal effect of aliphatic alcohols against aquatic stages of Aedes mosquitoes.

Effectiveness of certain long carbon chain aliphatic alcohols as ovicides and larvicides was investigated under laboratory conditions against eggs and larvae of Aedes aegypti and Aedes scutellaris. Out of the eight alcohols tested, three (1-decanol, 1-undecanol and 1-dodecanol) proved to be very effective. The hatching of mosquito eggs was inhibited at a dosage of 5 to 7 litres/hectare. First, third and fourth instar larvae were killed at a dosage of 3 to 7 litres/hectare. First instar larvae were more sensitive to the alcohols than the older larvae. The shorter carbon chain alcohols (2-mercapto-ethanol, 1-butanol, benzyl alcohol and 2-octanol) proved unsatisfactory due to their volatility and solubility. Longer carbon chain alcohols (1-tetradecanol, 1-hexadecanol and 1-octadecanol), Which are solid and wax-like at room temperature, proved unsatisfactory when dissolved in hexane and applied to eggs and larvae.