The repellency and toxicity of a petroleum-based proprietary horticultural oil, Sunspray 6E Plus, was tested against the greenhouse whitefly, Trialeurodes vapor-ariorum (Westwood), on greenhouse-grown chrysanthemums [Dendranthema ×grandiflorum (Ramat.) Kitamura cv. Iceberg]. A 2% (v/v) aqueous spray repelled adult whiteflies for at least 11 days after spraying and it was toxic to newly hatched and third stage larval whiteflies. No phytotoxicity was observed when four weekly sprays of 1%, 2%, and 4% oil were applied.