Effect of methoprene and diflubenzuron on larval development of the cat flea (Siphonaptera: Pulicidae)

Cat flea larvae, Ctenocephalides felis Bouche, exposed to glass surfaces treated with methoprene concentrations from 0.127 to 1,270 ng/cm2 did not emerge as adults. Most larvae died in the third instar, but those exposed to the 0.127 ng/cm2 concentration formed larval-pupal intermediates. Larvae exposed to glass surface treated with diflubenzuron concentrations from 12.7 to 1,270 ng/cm2 died during the process of molting in all three instars. Exposure of larvae to 12.7 and 127 ng/cm2 diflubenzuron resulted in 15 and 5.2% adult emergence, respectively.