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.