Development of Resistance to Malathion in Cat Flea (Siphonaptera: Pulicidae)

Abstract
Cat fleas, Ctenocephalides felis (Bouche’), under continual selection pressure with malathion exhibited a 12-fold increase in resistance ratio at LC50 after eight generations. Malathion-resistant fleas were twice as susceptible to D-limonene as were unselected fleas.