Evaluation of cyfluthrin and fenfluthrin for their insecticidal activity against three vector mosquitoes.

ABSTRACT

The EC50/EC90 concentrations of cyfluthrin and fenfluthrin were tested for their activity against different developmental stages of three important vector mosquitoes viz., Anopheles stephensi Liston, Aedes aegypti (Linn.) and Culex quinquefasciatus Say. The EC90 concentrations of both cyfluthrin and fenfluthrin showed ovicidal effect on An. Stephensi and Ae. aegypti whereas EC90 of cyfluthrin checked the hatching of eggs completely in Cx. quinquefasciatus. Fenfluthrin at EC50 concentration reduced the percentage of hatching significantly (p < 0.05) only in An. stephensi. Both the compounds were more active against the fourth larval instars of all mosquito species and cyfluthrin in culicines (17.3% Ae. aegypti = 9.1%) and fenfluthrin in anophenlines (An. stephensi = 36.8%) brought about maximum inhibition in adult emergence. Various types/degrees of morphogenetic aberrations were induced in all mosquito species on treatment with these compounds. Cyfluthrin treated female mosquitoes showed reduced fecundity rates in An. stephensi (p < 0.05), Cx. quinquefasciatus (p < 0.001) and fenfluthrin treated in An. stephensi (p < 0.5) and Ae. aegypti (p < 0.05). The fertility rates of all the mosquito species were significantly reduced (p < 0.001) by both the compounds.