Research was conducted in Albuquerque, Bernalillo County, New Mexico, to investigate the efficacy of orally administered bait cubes containing pyriproxyfen for control of the plague vector flea, Oropsylla montana (Baker), on rock squirrels, Spermophilus variegatus (Erxleben). Pyriproxyfen, accumulated in the squirrel blood, was ingested by feeding adult fleas, and was absorbed in the developing eggs preventing maturation of oocytes or hatching of larvae. Wild-caught squirrels were maintained in an environmentally controlled laboratory, housed in individual cages containing nest boxes, and infested with fleas to provide a continuous source of eggs. Caged squirrels were fed bait cubes containing concentrations of pyriproxyfen ranging from 60, 100 and 200 mg per kg of body weight to determine the dosage needed to prevent egg hatch. Flea eggs were collected from the squirrel cages weekly, and egg hatch was determined for fleas fed on each group of test squirrels and compared with that for fleas fed on an untreated control group of squirrels. Results showed that 100 and 200 mg/kg dosages of pyriproxyfen effectively inhibited egg hatch for nearly two months or more. At a dosage of 60 mg/kg, egg hatch rose to 50% during the third month after treatment, whereas the higher dosages of 100 to 200 mg/kg continued to prevent egg hatch at rates greatly exceeding 50%. A 60mg/kg dosage of pyriproxyfen provided flea egg mortality > 90% for nearly six weeks in at least one of three replicates and for four weeks from averaged data. Dosages of 100 and 200mg/kg caused > 90% mortality for nearly eight and eleven weeks, respectively, in at least one of three replicates and for seven and nearly nine weeks, respectively, from averaged data.
Species 1: Siphonaptera Ceratophyllidae Oropsylla montana
Species 2: Rodentia Sciuridae Spermophilus variegatus
Keywords: pyriproxyfen, control of plague vector fleas
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA