Inhibition of adult emergence and residual efficacy of pyriproxyfen against flies and mosquitoes

Abstract

This study evaluated the insect growth regulator pyriproxyfen (PPF) for its inhibitory effects on the adult emergence of fly (Musca domestica) and mosquito (Culex pipiens) larvae. Laboratory bioassays with a product containing 0.5% PPF were conducted using diet incorporation for fly larvae and water immersion for mosquito larvae at concentrations of 80, 160, and 320 mg/kg (flies) or mg/L (mosquitoes). PPF treatment reduced adult emergence in a dose-dependent manner. At 160 mg/kg (or mg/L), corrected adult emergence inhibition rates exceeded 80%, which meets regulatory thresholds for efficacy. Residual activity tests demonstrated sustained effects, with fly larvae showing 70% inhibition and mosquito larvae complete suppression (100%) at 45 days post-treatment. These findings confirm that PPF effectively disrupts metamorphosis of both species, with particularly strong and prolonged effects against mosquitoes.