The naturally derived compounds, abamectin, extract of neem seed (Azadirachta indica A. Jussieu), pyrethrin formulated with piperonyl butoxide and certain synthetic organic pyrethroid, carbamate, organophosphorus and chlorinated hydrocarbon insecticides were applied to mixed lifestage and adult populations of Bemisia tabaci (Gennadius) infesting poinsettia (Euphorbia pulcherrima Willdenow). Permethrin alone and in combination with piperonyl butoxide, fenpropathrin, esfenvalerate, abamectin and pyrethrin formulated with piperonyl butoxide provided greatest reductions in numbers of both nymph and adult B. tabaci. Neem seed extract reduced nymphs only and endosulfan and lindane reduced adults only. Lindane was the only insecticide evaluated that did not reduce the parasitoids, Encarsia sp. and Aleurodiphilus sp., below levels found on nontreated plants. Phytotoxicity to poinsettia occurred on plants treated with dimethoate, carbaryl, methamidophos and insecticides containing piperonyl butoxide.