Evaluation de l’effet insecticide de l’huile essentielle de Clausena anisata sur les stades de développement d’Anopheles gambiae Giles 1902 (Diptera: Culicidae), vecteur du paludisme

Abstract

Malaria is a serious health problem in many African countries. The Anopheles gambiae mousquito which is the major vector of this disease has developed resistance against synthetic insecticides such as pyrethrinoids. Essential oil may be an alternative to synthetic insecticides because of their efficacy and safety. In this work ovicidal, larvicidal and adulticidal activities of leaf essential oil from Clausena anisata were evaluated against Anopheles gambiae. The essential oil were extracted by hydrodistillation using clevenger apparatus. Adults mosquitoes were collected from OCEAC and were reared in the insectarium of the Laboratory of Zoology of Higher Teacher Training School of Yaounde. Eggs, third and fourth instars larvae and adults of Anopheles gambiae were exposed to the essential oil and were assayed in the laboratory by using the protocol of WHO (2005). The essential oil was tested at 0.833 %, 0.579 %, 0.694 %, 0.482 %, 0.401 %, 0.333 %, 0.278 %, 0.232 % and 0.194% for egg and larvae while tested at 2 %, 1.5 %, 1 % and 0.5 % for adults mosquitoes. The 72 h LC50 and LC90 values of Clausena anisata were determined for third and fourth instars larvae following probit analysis. The tkd50 and tkd90 were also determined. The essential oil yield was 0.242 %. This oil extracted from the leaves of Clausena anisata exhibited significant ovicidal, larvicidal and adulticidal activities. Clausena anisata essential oil has a significant effect on the egg of Anopheles gambiae with 1 % of eclosion at 0.833 % concentration. 72 h CL50 and CL90 values were 0.444% and 0.608 %; 0.427 % and 0.668 % respectively for third and the fourth instar larvae with 100% mortality at 0.833 %. The tkd50 and tkd90 values were 1.932; 18.589; 51.02; ˃ 60 and 14.603; ˃ 60 ; ˃ 60 ; ˃ 60 respectively at 2 %, 1.5 %, 1 % and 0.5 % with 100 % mortality after 24 h at 2 % for the adults of Anopheles gambiae. The essential oil of Clausena anisata has remarkable ovicidal, larvicidal and adulticidal activities which may be considered as sources for the production of natural biocides.