The effect of the insecticide permethrin 100 EC on Ae. aegypti, the vector for dengue Hemorrhagic Fever, was studied at the Entomology Laboratory, Health Research and Development of Health. Permethrin 100 Ec was sprayed (0.125 g/m2) to common media of resting places of the Ae. aegypti: board, nylon cloth, cotton cloth, wool and straw mats. A significant difference of mosquito knock down (LK 50)…