Susceptibility status of dengue fever vector Aedes aegypti, (L.) in Republic of Yemen

The aim of the present research work was to determine the current susceptibility level of larvae and adults of a field strain dengue fever vector Aedes aegypti (L.) to some conventional insecticides. Taking the values of LC50 (concentration required to kill 50% of mosquito larvae), the results showed that the mosquito larvae of A. aegypti were more susceptible to the OP insecticides sumithion (0.007 ppm) than acifon (0.019 ppm), actillic (0.049 ppm) and of onac (1.87 ppm) respectively, while the pyrethroids fendona (0.09 ppm) was more effective against larvae than aralin (1.24 ppm) by about 13.8 times. On the other hand, the findings revealed that the exposure of mosquito adult females to the diagnostic dosages of deltamethrin(0.05%), lambdacyhalothrin(0.5%), permethrin(0.75%), cyfluthrin(0.15%), malathion(5%) and fenitrothion (1%) caused 81, 75, 90, 84, 64 and 29% mortality, respectively. According to WHO criteria, the data indicated that adult mosquitoes of the field strain A. aegypti were resistant to the insecticides lambdacyhalothrin, malathion and fenitrothion but were tolerant to deltamethrin, permethrin and cyfluthrin.