Studies have reported differential attractiveness of yellow, white or blue sticky cards to greenhouse pests, especially to Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) and Trialeurodes vaporariorum Westwood (Homoptera: Alyerodidae). The main aim of this study was to determine whether yellow or blue sticky card offers a better option in monitoring or mass trapping these sympatric greenhouse pests. Laboratory study that included a multiple choice and no-choice tests to observe the attractiveness of blue, yellow, white or green sticky card to F. occidentalis and T. vaporariorum was conducted. Also, a glasshouse study was conducted to determine better composite attractiveness of yellow or blue sticky card. F. occidentalis showed higher preference to blue and yellow sticky cards in laboratory study and blue captured the highest number of F. occidentalis in glasshouse followed by the yellow. However, while the blue sticky card captured few T. vaporariorum, the yellow sticky card captured the highest number of T. vaporariorum in both laboratory and glasshouse tests. Since yellow sticky card received composite affinity of both F. occidentalis and T. vaporariorum, placement of yellow sticky card for the greenhouse pests, rather than blue or yellow targeted to individual species, is recommended for economical and optimal monitoring and/or mass trapping success of the tested greenhouse pests.