Abstract Nylon shag pile carpet discs (5 inches diam) were treated with either 11.7% Dursban ME, 41.5% Dursban LO or Pennwalt 23.5% TD 2247. Each formulation was mixed with water and applied at the rate of 1 gal/1000 ft2. Each carpet disc was treated by the use of a 1 gal Hudson pressurized hand sprayer calibrated to deliver 0.23 oz/s at 20 psi. Control carpet discs were sprayed with water only. On the day of treatment, 7, 14, and 28 days posttreatment, a treated carpet disc was placed in the bottom of a 1 gal jar and ca. 25 adult cat fleas were added. All treatments were replicated 3 times at each time interval and the experiment was replicated twice. At 24 h posttreatment, dead and live fleas were recovered by brushing each carpet disc vigorously for ca. 1 min with a hair brush within a 5 gal plastic bucket. The discs were then submerged in water to recover any additional live fleas. Nylon shag pile carpet discs (3.5 inches diam) were treated as described above and all formulations were tested for their effects on adult cat flea emergence. On the day of treatment, 7, 14, and 28 days! posttreatment, ca. 0.25 g of dried blood, ground cat chow mixture (3:20), and 25 cat flea eggs were placed within the fibers of each treated carpet disc. \ Infested discs were then placed into 1 pt fonda containers, covered with a fine cloth screen to contain emerging adult fleas and stored at 25°C at 80% RH. - All treatments at each time interval were replicated 3 times and controls replicated 6 times. When >50% of the adult fleas had emerged in the control containers, treatments were evaluated for % adult emergence by recovering adult fleas as described above. In both tests carpet discs were used only once for each test interval. All carpet discs were stored at ca. 25°C between infestation periods.