Larvicidal Activity of a Neem Tree Extract (Azadirachtin) Against Mosquito Larvae in the Republic of Algeria

An insecticide containing azadirachtin, a tree ﺮﻴﺛﺄﺗ ﺔﺳارد ﺚﺤﺒﻟا اﺬه لوﺎﻨﺗ (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 by the Azadirachtin after treatment of the fourth instar and pupal stage. The tretment also prolonged the duration of the larval stage. The results show that the Azadirachtin is promising as a larvicidal agent against Culex pipiens, naturally ocurring biopesticide could be an alternative for chemical pesticides.