Laboratory and Field Tests of Union Carbide 57193 4E for Efficacy Against Mosquito Larvae, 1979 and 1980

A laboratory test was conducted against C. quinguefasciatus larvae in late third or early fourth instar. Insecticide concentrations ranged from 0.1 to 40 ppm. Ten larvae were placed in each 237 ml test paper cup. The tests were replicated at least 3 times and larval mortality was ascertained 24 hours posttreahnent. UC 57193 was field tested in a ricefield plot 6.096 m X 48.77 m (0.069h). The initial treatment of material was 560.9 g ai/surface h. This was increased in a second experiment to 1121.8 g ai/surface h. Water was added to improve titration and the entire mixture placed in a 3.784 I polyvinyl container and dripped into the plot. Two 22 gauge hypodermic needles were inserted in the bottom of the container and the material dripped into the field at the irrigation source. Late third or early fourth instar Ps. columbioe were field collected from natural breeding sites for this test. The larvae were confined in bioassay cups made of 10.16 cm diameter plastic irrigation pipe cut into 26.32 cm sections. The bottom of each cup was covered with fine nylon mesh. A series of three 1.27 cm holes cut 2 cm above the bottom were also covered with mesh. These holes provided for circulation of treated plot water within the cup. Ten larvae were confined in each of 4 bio-assay cups and the four cups were placed midway along each of four levees. The field test was replicated three times for each treatment level. A 24 hour post-treatment mortality survey was conducted on each test. A laboratory test against Ps. columbioe was conducted concurrently with the field test using water samples taken from the field plot immediately after titration was completed. In the laboratory, the field water was placed in paper 237 ml paper cupsand ten Ps. columbiae larvae were introduced. Posttreafment surveys of larval mortality were conducted at 24 hours.