Technical Abstract: In a series of studies conducted in Hawaii under semi-natural conditions, we determined the behavioral response of sexually mature, host-seeking melon fly (Bactrocera cucurbitae (Coquillett)) females to different types of visual and chemical host-associated stimuli with the main aim of developing a monitoring device for females. Experiments were conducted both at the ground level and at the tree-canopy level so as to take into account the foraging behavior of adult melon flies. Among fruit mimics of either spherical or cylindrical shapes and coated with one of eight different artificial pigments, females were particularly attracted to objects of spherical shape, colored either yellow or white followed by orange; these three pigments offered the highest reflectance values. Among four different types of host plant odor evaluated, cucumber was the most attractive for females when compared with other cultivated hosts (zucchini, papaya, or tomato) or compared with one of its major wild hosts in Hawaii, ivy gourd (Coccinia grandis (L.) Voigt). A combination of both visual (i.e., yellow spheres) and olfactory (i.e., cucumber odor) stimuli elicited the highest response of females compared to each stimulus offered alone. We discuss our results in relation to the potential implementation of improved monitoring and/or attract-and-kill strategies for melon flies in Hawaii.