FIELD EVALUATION OF THE LARVICIDAL EFFECTIVENESS, EFFECTS ON NONTARGET SPECIES AND ENVIRONMENTAL RESIDUES OF A SLOW-RELEASE POLYMER FORMULATION OF CHLORPYRIFOS, MAR-OCT 73

摘要

Tests conducted in woodland pool ant rice culture habitats determined mosquito larvicidal activity, effect s on nontargets, and residues maintained within the aquatic environment resulting from the application of a slow-release chlorinated polyeihylene (CPE) pellet formulation of 10.6 percent chlorpyrifos [0,0-diethyl 0-(3,5,6-trichloro-2 pyridyl) phosphorothioate]. Dosage rates of 250, 500, 1000, and 2000 ppb active ingredient, based on total initial 2elease, were utilized.nIn-pool bioassays, natural larval mosquito infestation rates, chlorpyrifos residues in habitat water, and LD50 and LD99 determinations for selected mosquito species indicated sufficient chlorpyrifos was present to control larval mosquitoes for over 30 weeks.