An effective means of supplying food to Cotesia vestalis, the larval endoparasitoid of the diamondback moth, Plutella xylostella, was examined in a laboratory and an experimental small greenhouse. Compared to the red and blue boards, yellow boards significantly attracted parasitoids in the laboratory and in the small greenhouse, the yellow feeding site was more effectively utilized by parasitoids than the white one. The parasitoid tended to utilize a feeding site hung 50 cm above ground more than one hung 200 cm above ground, hence we concluded that color and height were important factors for the recognition of the feeding sites by C. vestalis.