Captures of Rhagoletis indifferens (Diptera: Tephritidae) and nontarget insects on red spheres versus yellow spheres and panels.

Sticky red spheres can be used to capture western cherry fruit fly, Rhagoletis indifferens Curran (Diptera: Tephritidae), but red spheres have not been definitively shown to be more attractive than yellow traps. The objective of this study was to compare fly captures on ammonia-baited red spheres and yellow spheres and panels so that sensitive detection traps for fly management can be identified. Nontarget insects could interfere with fly captures, so weights of nontarget insects on traps were also determined. Yellow spheres and panels generally caught more flies than red spheres. More males than females were caught on nearly all red and yellow traps. Saffron Thread, Marigold, Sunny Summer, and Yam Yellow spheres and panels were bright yellow and generally caught more flies, especially females, than Cherry Cobbler Red or Tartar Red spheres. Twenty Carat Yellow and Glorious Gold spheres and panels were less bright and caught fewer flies than bright yellow traps and similar numbers of flies as Tartar Red spheres, respectively. Dry weights of nontarget insects on at least one yellow trap type were greater than on red spheres in only 4 of 10 tests. Results show that bright yellow spheres and panels capture more R. indifferens than red spheres and do not consistently capture greater amounts of nontarget insects than red spheres, suggesting that they should be used instead of red spheres for detecting this fly.