Abstract:  Various colors have been used as visual cues to trap insect pests. For example, yellow traps for monitoring and controlling of the fruit flies have been used for a very long time. However, the chromatic cue of using color traps has never been quantitatively investigated. To reveal which wavelengths are most attractive to the fly, experiments were conducted to evaluate the preferences of Bactrocera cucurbitae to different colors. In this study, RGB values and virtual wavelengths were converted each other based on Dan Bruton’s wavelength to RGB function. Eight color papers were printed by color printer based on RGB values ［(0, 213, 255), (0, 255, 146), (54, 255, 0), (129, 255, 0), (195, 255, 0), (255, 255, 0), (255, 190, 0) and (255, 119, 0)］ and were chosen to test the color preference of the melon fly, Bactrocera cucurbitae in an octagon maze, and their equivalent wavelengths were 480 nm, 500 nm, 520 nm, 540 nm, 560 nm, 580 nm, 560 nm, and 600 nm, respectively. The color papers with the spectrum between 520-560 nm showed higher attractiveness than the others, and that with the spectrum of 540 nm (chartreuse green, with RGB values of 129, 255, 0) showed the highest attractive rate. In addition, field preference experiment was done to confirm the effect of the chartreuse green color. The results suggest that chartreuse green stimuli (spectrum 540 nm) should be a crucial cue to attract B. cucurbitae, and chartreuse green sticky traps could be a useful device for monitoring and managing B. cucurbitae.

Key words:  Bactrocera cucurbitae, color preference, RGB value, virtual wavelength, sticky trap