Field Evaluation of the Long-Term Larvicidal Effectiveness of Polymer Formulations of Dursban (Trade Mark), May 1970-October 1971

摘要

Field tests were conducted for 18 months to evaluate the long-term larvicidal effectiveness of three pellet formulations of Dursban (O,O-diethyl O-(3,5,6-trichloro-2-pyridyl) phosphorothioate). The three formulations were: 9.9 percent Dursban in polyethylene (PE) (Specific gravity 1.0) and 11.5 percent Dursban in chlorinated polyethylene (CPE) specific gravity >1.0). Each formulation was applied to plastic-lined artificial pools in May 1970, at a dosage of 5.0 ppm, equivalent to 137 pounds of 9.9 percent PE formulation per acre, 136 pounds of 10.0 percent PVC formulation per acre, or 117 pounds of 11.5 percent CPE formulation per acre. Single applications of the formulation resulted in the following 18-month average Dursban residues: 14.7 parts per billion (ppb) for the 9.9 percent PE FORMULATION: 25% PPB FOR THE 2)5) PERCENT PVC formulation; and 2.5 ppb for the 11.5 percent CPE formulation. During 18 months in the pools, the formulations released the following percentages of Dursban originally formulated: 91.6 percent for the 9.9 percent PE formulation; 16.7 percent for the 10.0 percent PVC formulation; and 28.8 percent for the 11.5 percent CPE formulation. (Author)