Laboratory Evaluation of Igr's and Toxicants Against the Larvae of the Oriental Rat Flea, 1981

A 10-g sample of a mixture of fine sand and flea larval diet was placed in a 25-ml screwcapped vial. An appropriate concentration of technical IGR or toxicant in 500 ul of acetone was added to the mix, and after it was stirred, the acetone was evaporated at room temperature. Next, 200 ul of water was added and stirred into the mix. Twenty-five laboratory-reared 2nd stage larvae were added. Vials were then covered with 0.3 mm mesh marquisette cloth and held in separate chambers at 75% RH, 29 ± 1°C, and 8/16 dark/light cycle. Each test was replicated 2-6 times. Control vials containing the sand-diet mix were treated with the acetone only and handled in the same manner as test vials. The vials were examined weekly for 2 or 3 wk, and any cocoons were removed and placed in 3.7-ml shell vials and covered with the marquisette cloth. Twenty-one days after removal of the cocoons, any emerged fleas were killed with chloroform and counted. The highest concentration of IGR or toxicant tested was 100 ppm; dilutions to 1.0 ppb were tested, as needed, to obtained reduced mortality.