Attraction of Laboratory-cultured and Wild Dacus oleae1 Flies to Sticky-coated McPhail Traps of Different Colors and Odors

Abstract

Under field conditions, we compared the responses of laboratory-cultured and wild olive flies, Dacus oleae (Gmelin), to McPhail invaginated glass traps of different colors baited with different odoriferous solutions. The order of treatment preference and degree of distinction between treatments were essentially the same for all flies. A smaller percentage of released lab flies than released wild flies was recaptured, however. Olive flies arriving at a clear, odor-baited McPhail trap first landed on the trap's exterior. Some then proceeded into the interior and were captured in the solution but others flew away. Hence, the effectiveness of a clear McPhail trap baited with a 2% Rodia,® 1.5% borax solution (the most attractive odor lure tested) or a 2% ammonium sulfate solution (the standard odor lure for olive flies) could be increased about twofold and threefold, respectively, by coating the trap exterior with Bird Tanglefoot® (BT) so as to entangle all arriving flies. A BT-coated McPhail trap painted daylight fluorescent yellow (the most attractive color tested) captured more olive flies than a BT-coated clear one when both were baited with 2% ammonium sulfate or water, but not when both were baited with 2% Rodia, 1.5% borax. More Ceratitis capitata (Wiedemann) flies were captured by BT-coated yellow McPhail traps than by any others, irrespective of the nature of the odor solution.