Whiteflies adults are strongly attracted to yellow. They fly from hosts toward light. When landing on new hosts, they walk to shaded underside of leaves to feed and oviposit. Based on these observations, we developed a trap for survey and monitoring Bemisia argentifolii Bellows and Perring adult population density under field conditions. Results indicate that the trap catches reflected seasonal population density changes. The whitefly trap may be a useful tool for survey or population monitoring purposes.