Abstract An insecticide containing azadirachtin, a tree
(Azadirachta indica) extract, was tested against Culex pipiens mosquito larvae and pupae in east of the Republic of Algeria under laboratory conditions. First, after treatment of larval stage, LC50 and LC90 values for Azadirachtin were 0.35 and 1.28 mg/L in direct effect and 0.3-0.99 mg/l in indirect effect, respectively. Second, after treatment of the pupal stage, the LC50 and LC90 in direct effect were measured as0.42 -1.24mg/l and in indirect effect was 0.39mg/l-1.14mg/l respectively. Mosquito adult fecundity were markedly decreased and sterility was
increased