Circular yellow sticky trap with black background enhances attraction of Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae)

Yellow sticky flat traps were cut into six geometrical shapes (square, circle, semi-circle, diamond, triangle, and inverted triangle) to evaluate their attractiveness to Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). The square was used as a standard to compare with other shapes in the laboratory. Circle was the most effective, attracting 2.7 and 1.5 times more thrips in choice and no-choice experiments, respectively. Four different background colors were also employed in the circular trap, and their efficacies were compared. In both choice and no-choice tests, the circular yellow sticky trap on a black background attracted a significantly higher number of thrips than on a yellow, blue, or green background. In addition, the higher ratio of a black background to yellow sticky foreground enhanced thrips' attraction in the choice test. Based on these results, the efficacy of circular yellow sticky traps (5 cm diameter) on a black background (12 cm wide×12 cm length) was compared to commercial yellow sticky traps (5 cm wide×8 cm length) in a strawberry greenhouse. The modified trap attracted 2.3–21 times more F. occidentalis than the commercial yellow sticky trap. Therefore, the modification of yellow sticky flat traps to a circular shape on a black background would be a good addition to the thrips management program.