Attraction of Adult Plum Curculios (Coleoptera: Curculionidae) to Host-Tree Odor and Visual Stimuli in the Field

Field tests were conducted to determine if plum curculios, Conotrachelus nenuphar (Herbst), responded to host odor and/or visual cues to locate host trees. Experiment 1 investigated the role of odor in host location. Host branchlets (apple leaves and fruit) were compared with non-host branchlets (maple leaves). Significantly more released color-marked plum curculios arrived on screen cages containing apple branchlets than on screen cages containing maple branchlets. Experiment 2 investigated the role of visual cues, with or without host odor, in host tree location. Plum curculios arrived preferentially on 60 cm wide × 130 cm tall sticky green rectangles (intended to mimic the canopy of a small tree) with associated caged apple branchlets than on sticky clear Plexiglas rectangles with caged apple branchlets or on sticky green or clear Plexiglas rectangles with caged maple branchlets. These data suggest that plum curculio adults may use both odor and visual cues to locate host trees during spring migration from overwintering sites.