In a comparison of test materials for control of Trialeurodes vaporariorum (Westwood), resmethrin was the most effective spray and controlled all stages but the eggs. Resmethrin mists and aerosols gave good control of whitefly adults and young nymphs in the winter, but were less effective in the warmer months. Azinphosmethyl, Dasanit® ( O,O -diethyl O -[ p -(methylsulfinyl) phenyl] phosphorothioate), and parathion also gave good control of nymphs in spray tests. Phytotoxicity of the resmethrin formulations appeared minimal except with poinsettia. When resmethrin mist was applied once a week (1 or 0.5 g AI/1000 ft3) it gave excellent control of whitefly during the cool winter, but effectiveness decreased as temperatures increased. By mid-June, applications of the higher dose gave only fair control. Generally, the mists controlled the adults, crawlers, and young nymphs, but were ineffective vs. eggs, older nymphs, and pupae. However, resmethrin 2 EC applied as a spray once a week for 4 weeks virtually eradicated infestations.