Weathering of 3-component synthetic food cones: effects on residual amount, release rate, and field capture of 3 pest species of fruit flies (Diptera: Tephritidae).

Abstract

Food-based baits are an important component of trapping networks designed to detect invasive tephritid fruit flies (Diptera: Tephritidae). An aqueous solution of torula yeast plus borax (TYB) is widely used, but synthetic food lures have been developed to facilitate field procedures, ensure standard composition, and lengthen the interval of bait attractiveness. Cone-shaped dispensers, containing ammonium acetate, putrescine, and trimethylamine (so-called 3C food cones), are currently being used in some large-scale trapping systems (e.g., Florida). Prior work in Hawaii showed that traps baited with 3C food cones capture similar numbers of Mediterranean fruit flies (medflies), Ceratitis capitata (Wiedemann), as TYB-baited traps after 1-2 wk of weathering but capture fewer medflies thereafter. In addition, 3C food cones attract fewer oriental fruit flies, Bactrocera dorsalis (Hendel), and melon flies, Zeugodacuscucurbitae (Coquillett) than TYB even when the food cones are freshly deployed. The current study describes an additional trapping experiment that expands upon earlier work by (i) presenting 3C food cones either unbagged (as done previously) or in nonporous or breathable bags to possibly reduce volatilization and lengthen bait effectiveness and (ii) measuring the content of the 3 components over time to potentially associate fruit fly captures with the loss of these food cone constituents. Implications of these findings for fruit fly surveillance programs are discussed.