抄録
Insecticide susceptibility of a Sakai (Osaka) strain of adults of the cat flea, Ctenocephalides felis, was evaluated using 26 chemicals after colonization for 6 months. Cat fleas were reared on domestic cats by the method described by Hudson and Prince (1958). The following results were obtained. 1. According to the experiments for the influence of elapsed time after adult-emergence, insecticide susceptibility remained almost unchanged in the individuals upto 3 days old, then it rose rapidly 7-8 days after emergence. 2. The effects of six insecticides on the cat flea were compared by exposing adults to insecticide residues of different dosage for limited times. The higher mortalities tended to occur with longer contact times. Generally, the ratios (LC_<50> for 1hr contact/LC_<50> for 24hr contact) based on the LC_<50>'s of pyrethroids between the 1hr and 24hr contact were greater than those of organophosphates. 3. Toxicity (μg/(cm)^2) based on the LC_<50>'s were determined by the successive contact method. Dichlorvos and fenthion were most toxic against the cat flea. Other insecticides tested, in descending order of toxicity, were chlorpyrifos, fenitrothion, diazinon, propoxur, fenobucarb, carbaryl, metoxadiazone, cyfluthrin, empenthrin, trichlorfon, resmethrin and prallethrin. 4. The data of insecticide susceptibility of the cat flea presented here were compared with those reported by several workers from various localities in USA. The Sakai strain was more susceptible to pyrethroids and carbamates, while more tolerant to organophosphates, as compared with a susceptible (California) strain.
