Evaluating the Adulticidal Effect of Alpha-Cypermethrin Against Malaysian Dengue Vector Aedes albopictus

The efficacy of a pyrethroid insecticide; alpha-cypermethrin against dengue vector Aedes albopictus adult populations from various types of residential and agricultural areas in West Malaysia was evaluated through the adult mosquito bioassays. Sugar-fed Ae. albopictus adult females aged 3-5 days old from each study area were exposed to alpha-cypermethrin 0.05% for an hour. The mortality percentages were calculated at 30 minutes of exposure and 24 h post-exposure. At 30 minutes of exposure, Ae. albopictus adult populations from dengue-risk residential areas (34.19 min) and oil palm plantations (56.53 min) exhibited the shortest and longest time to obtain the 50% mortalities of the population (LT50), respectively. At 24 h post-exposure, other than the reference strain, Ae. albopictus adult populations from rubber estates (99.67%), dengue-free residential areas (99.67%) and dengue-risk residential areas (98.33%) demonstrated susceptibility to alpha-cypermethrin 0.05%. These results revealed the worthwhile adulticidal effect of alpha-cypermethrin which could be used in the future vector control strategies at rubber estates, dengue-free residential areas and dengue-risk residential areas selected in this study.