Clinically, malaria is a hemolytic feverish disease associated with fever, chills, anemia and spelenomegaly, and its agent parasite is named Plasmodium spp which lives inside the red blood cell and it is transmitted by bloodeating mosquitoes belonging to Anopheles genus (1). Given that nearly one billion people of the world's population at risk of malaria and

Introduction: Culex spp, a prevalent mosquito in many tropical countries, causes filarial fever among human beings. The easiest way to prevent this disease is to eliminate the vector. The present study aimed to compare the effect of the extract of aerial parts of Hyoscyamus niger and Nerium oleander on larva killing. Materials and methods: Aerial parts of the plant were collected and dried. Methanol was used for extraction and the solvent was removed with a rotary evaporator. Mosquito larvae were collected and identified from stagnant water pits and ponds around Birjand, Iran. The larvae were then placed on a plate containing a certain concentration of the extract of oleander or henbane separately, and their mortality rates were recorded and analyzed. Results: H. niger and N. oleander alcoholic extract of aerial parts both had a positive effect on eliminating larvae of the Culex spp., but the flower extract of henbane was the most powerful extract after 72 hours (LC50= 0.46 ppm) and the stem extract of henbane was the weakest one (LC50= 37.57 ppm). Conclusion: Due to the strong larvicidal effect of the henbane extract in 72 hours compared to other extracts, it is suggested that it be used as an organic pesticide to eliminate Culex spp larvae.