The Culicidae family constitutes a plague of health risks. These biting insects are harmful to human populations and pass on infectious diseases such as malaria. Since chemical control has limited effectiveness against mosquitoes, biological control has become more prevalent. We conducted toxicological tests with an ethanolic extract of fresh leaves of Peganum harmala on Culex pipiens larvae (L4). The results show a larvicidal effect that resulted in an LD 50% in 10.17 days for a 2 g/L dose and an LD 50% in 5.76 days for a 4 g/L dose. A sub-lethal dose was tested on the different stages of the studied species, and a significant difference was observed between the duration until hatching in female eggs from the control group and eggs from the treated group (P = 0.01). There was a considerable prolongation of each stage of the development cycle in the treated group, in the egg-laying period, in the hatching period, and also in the duration until the emergence of the adults. These results show that P. harmala causes retardation and inhibition of moulting and development of Culex pipiens.
