BOUKHARI, Keltoum2023-03-222023-03-222013https://dspace.univ-ghardaia.edu.dz/xmlui/handle/123456789/5822The study of the aerial parts extracts toxicity of Euphorbia guyoniana Boiss. & Reut (Euphorbiaceae) collected in Wadi Metlili, northern Sahara of Algerian on the larvae of Culex pipiens (Diptera, Culicidae) in the third stage. The aqueous extract of Euphorbia guyoniana generates a total mortality was reached after less than 2 hours of Culex pipiens L3 larvae, the mortality rate observed was 100% for concentrations 100%, 75%, 50% and25 %. In addition, the calcul of the CE 50 and 90 were conducted to assess the toxicity degree of these plant extracts vis-à-vis third stage larvae of Culex pipiens. The results show that the concentrations causing 50% mortality and 90% of larvae are 0.0015 mg / ml and 0.0094 mg / ml, respectively. Otherwise, the assessment of lethal time 50 (LT 50 ) shows that the aerial part extract of Euphorbia guyoniana exhibits a particular speed of action especially a high concentrations with 100%, 75%, 50% and25%.frEuphorbia guyoniana, Euphorbiaceae, plant extract, Culex pipiens.Euphorbia guyoniana, Euphorbiaceae, extrait végétal, Culex pipiens