Bioefficacy of Azadirachtinin Controlling Culex pipiens pipiens (Diptera: Culicidae)

Azadirachtin was tested for its effects against first p pand second instars larvae of mosquito culex pipiens pipiens (diptera: culicidae), laboratory reared larvae were exposed to 0.125 ; 0.250; 0.500 and 0.750 mg/ l of azadirachtin in laboratory of biology animal application, biology department , university of badji mokhtar, annaba, algeria. larvicidal assays were conducted according to standard world health organization (who) .the results have been exploited according to classic statistical methods. a linear correlation was revealed between concentration and larval mortality. at first stage, larval mortality increased from 45.83 % at 0.125 mg /l to 94.44 % at concentration 0.750mg /l of azadirachtin in direct effect. the lethal concentration lcr16r, lcr50r and lcr90r in direct effect was measured as 0.056; 0.166 and 0.663 mg/l respectively. cumulate mortality increased from 54.28% to 95.71% at 0.125mg/l and 0.750mg/l respectively. the lcr16r, lcr50 rand lcr90r values for azadirachtin were 0.040 ; 0,127 and 0.555mg/l respectively. at second stage, larval mortality increased from 39.66 % at 0.125 mg /l to 87.66 % at concentration 0.750mg /l of azadirachtin in direct effect, the lcr16r, lcr50 rand lcr90r values was 0.063; 0.190 and 0.891 mg/l respectively. in indirect effect the mortality increased from 49.27% to 91.54% at 0.125mg/l and 0.750mg/l respectively, the lcr16r, lcr50 rand lcr90r values was 0.041; 0.141 and 0.724 mg/l respectively. after a comparison between the two stages showed that the first stage is the most sensitive than the second stage .the results show that the azadirachtin is promising as a larvicidal agent against culex pipiens pipiens naturally occurring biopesticide could be an alternative for chemical pesticides.