1.Evaluation of pyriproxyfen against Aedes aegypti and Aedes albopictus from Penang, Malaysia
Mohamad N.A. ; Ishak I.H. ; Hasan H.A.
Tropical Biomedicine 2026;43(No. 1):90-102
Aedes aegypti and Aedes albopictus mosquitoes are the primary vectors of tropical diseases, including
dengue fever (DHF), chikungunya, and Zika, particularly in tropical regions such as Malaysia. Vector
control efforts are now increasingly focused on biological and environmentally friendly approaches, one
of which is using insect growth regulator (IGR)-based insecticides such as pyriproxyfen. Pyriproxyfen
works by disrupting the metamorphosis process of mosquito larvae into adults without causing direct
death, but it is effective in inhibiting the emergence of adult mosquitoes by more than 90%, depending
on the dose and environmental conditions. This study evaluated the concentration-dependent effects
of pyriproxyfen on laboratory and field populations of Aedes spp. Laboratory strains exhibited 100%
adult mortality at 1.04 ppm (Ae. aegypti) and 1.08 ppm (Ae. albopictus), whereas field populations
required 1.15 – 1.71 ppm depending on locality. LC50 values were lowest in laboratory strains (0.267
ppm for Ae. aegypti and 0.236 ppm for Ae. albopictus), while field strains ranged from 0.326 to 0.571
ppm. LC95 values followed a similar trend, with 1.026 ppm (Ae. aegypti) and 1.107 ppm (Ae. albopictus)
in laboratory strains. Inhibition of emergence (IE%) was high in laboratory strains, reaching 97.89% at
0.50 ppm in Ae. aegypti and 63.54% at 0.50 ppm in Ae. albopictus. Field populations required higher
concentrations for similar suppression, with IE% ranging from 17.68 – 98.23% in Ae. aegypti and 13.14-
98.24% in Ae. albopictus, peaking at 1.50 ppm. From this finding, it is suggested that pyriproxyfen
effectively inhibits adult emergence in both laboratory and field populations, with laboratory strains
more sensitive at lower concentrations and field strains responding at higher doses. These results provide
strong evidence for pyriproxyfen as an effective, adaptive, and sustainable component of integrated
vector management in Malaysia.


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