Culex pipiens is a predominant house-resting mosquito in different countries. Third larval instar of Culex pipiens were exposed to sub-lethal concentration LC25of pet-ether extract for Solenostemma sp, Rosmarinus sp. and Artemisia sp. to study their effect on some enzymatic activities of larvae after 24 hours. AchE enzyme showed high activity in all application extracts. While, showed lower in enzyme activity of -est, β-est in comparison with control. Glutathione S Transferase showed no difference with control sample. Mixed function oxidase appears high activity with Solenostemma argel and Artemisia sp. While appears low activity with Rosmarinus sp. comparing by control larvae. Finally, these extracts affect the nervous system of tested mosquitoes in different degrees and their energy system and can be used alternate
to chemical insecticides in Integrated Vector Management program (IVM).