Pitfall traps with above-ground silhouettes of various colors and diameters were used in field tests to evaluate the role of vision in host orientation by adult pales weevils, Hylobius pales, and pitch-eating weevils, Pachylobius picivorus. White traps (11 em outer diameter) baited with ethanol and turpentine caught significantly more weevils than similarly baited black or green traps (11 cm outer diameter). Trap diameter (range of 6-22 cm outer diameter) did not affect trap catch. Pitfall traps can be used to monitor root weevil populations in young pine plantations and Christmas tree farms, where they are major pests. These results demonstrate that visual and chemical cues can be integrated to improve trap efficiency.
Hunt, D.W. A. and Raffa, K. F.
"Orientation of Hylobius Pales and Pachylobius Picivorus (Coleoptera: Curculionidae) to Visual Cues,"
The Great Lakes Entomologist, vol 24
Available at: https://scholar.valpo.edu/tgle/vol24/iss4/3