A second choice experiment was conducted to determine th extent to which adult whiteflies that had settled on poinsettia would move to cucumber. This experiment is referred to as a conditional choice test because the whiteflies had initially settled on poinsettia before they were provided a choice of another plant. Before the test, potted poinsettia plants(11 weeks old from propagated cuttings) were placed on a greenhouse bench(1.5 x 25 m) to infest the plants with adult whiteflies. One-hundred adults(mixed age and sex) were collected in a 25 ml glass vial and placed next to each poinsettia and the whiteflies released from the vial. After 24 h, each whiteny-infested poinsettia was examined to record the number of adults settled on the plant. Each poinsettia was then carefully moved into a BugDorm cage containing one uninfested potted cucumber(4 weeks old from seed) (P+C) or one uninfested potted poinsettia(P+P).The two plants in a cage were placed 25 cm apart from center to center and their locations in a cage were randomly assigned to the left or right side. The number of adult whiteflies on the underside of the leaves was counted at 6,24,48and 72 h. The experiment was carried out at 20-25°C and a L14:D10 photoperiod in a research greenhouse and the test was replicated 10 times.