Observations on the susceptibility of Ctenocephalides felis (Siphonaptera: Pulicidae) to malathion and permethrin in Tanzania.

ABSTRACT. Laboratory-reared Ctenocephalides felis (Bouche) adults were tested with 0.5% malathion and 0.5% permethrin, using the standard WHO methods. After 24 h exposure to malathion (3.6 mg/cm²), 92% of the fleas died. The LT₅₀ for malathion was approximately 8 h. Permethrin (0.45 mg/cm²) produced 100% mortality of exposed insects after 24 h while with a higher dose (0.9 mg/cm²) all fleas died after 8 h exposure. LT₅₀ for the two doses of permethrin were 7.7 and 1.05 h, respectively. The failure of the diagnostic dose of malathion to kill 100% of the population was attributed to resistance. Permethrin is a suitable pesticide for controlling fleas of domestic animals in Tanzania. [ABSTRACT FROM AUTHOR]