Ovicidal effects of the juvenile hormone analogue, pyriproxyfen, against the cat flea, Ctenocephalides felis (Bouche)

Abstract

Ovicidal effects of the juvenile hormone analogue, pyriproxyfen, against the cat flea, Ctenocephalides felis, were evaluated by laboratory test. Flea eggs aged for <2,4-6,10-12,22-24,or 46-48hrs after oviposition were exposed to pyriproxyfen on filter paper disks for 24hrs at 26℃ and 60%RH. The ovicidal effects were observed when flea eggs aged within 2hrs were exposed to pyriproxyfen, showing that the IC_<50> was 0.021μg/(cm)^2. Higher hatch inhibition tended to occur with younger aged groups of flea eggs. However, hatching of the eggs older than 46hrs was not inhibited. In the experiment on the influence of pyriproxyfen against flea eggs exposed for some fixed time duration, higher inhibition of hatching tended to occur with longer exposure times for any aged group of the flea eggs. Adult males exposed to the pyriproxyfen-treated glass surface (25,10,1μg/(cm)^2 as active ingredient) and females untreated, or vice versa, were infested on a mouse to investigate the ovicidal inhibition effect on flea eggs. The hatchability of eggs laid by females decreased with the increase of dosage. The sexual transmission of sterility by pyriproxyfen-treated males was also observed. However, the influence of pyriproxyfen wore off with time as the fleas aged after exposure.