Red Spheres and Yellow Panels Combined to Attract Apple Maggot Flies1

Rhagoletis pomonella (Walsh) were trapped in an apple orchard on Stikem®-coated 7.5-cm red disks and spheres, on 30×30- and 30×40-cm yellow panels, and on combinations of spheres and panels. The sphere alone and the sphere plus panel combinations were preferred by the flies to the panel alone. The sphere-panel trap captured flies which were apparently responding to the visual stimuli of both the foliage and the apple. Relative numbers trapped on the panel and on the sphere changed with time. As the season advanced the panel was less attractive than the sphere. The sphere-panel trap was the most efficient. More flies were captured on the central area of the panels than on the sides. A disk trap was less effective than a sphere.