Evaluation of Odor Lures for Use with Red Sticky Spheres To Trap Apple Maggot (Diptera: Tephritidae)

Abstract

Synthetic odor lures were evaluated in association with red sticky sphere traps for their attractiveness to apple maggot flies, Rhagoletis pomonella (Walsh). Spheres baited with either butyl hexanoate (fruit odor) alone, ammonium carbonate (food odor) alone, or both were tested in an artificial orchard and several commercial orchards. In artificial orchard assays with released flies of high or low egg load, the combination of butyl hexanoate and ammonium carbonate was more attractive than either odor alone or unbaited spheres. Spheres baited with butyl hexanoate or ammonium carbonate alone were more attractive than unbaited spheres. This pattern was consistent for both high egg load, protein-fed flies, and low egg load, protein-starved flies. In commercial orchards, butyl hexanoate-baited spheres captured significantly more flies than ammonium carbonate-baited or unbaited spheres, which did not differ in attractiveness. Butyl hexanoate was as attractive as the combination of butyl hexanoate and ammonium carbonate. Ratios of flies captured on butyl hexanoate baited spheres to lies captured on unbaited spheres in commercial orchards declined slightly from 5.8:1 to 4.4:1 over the 10-wk trapping season. Dissections of captured females suggested that there was no difference between the odor types in terms of egg load and sexual maturity of attracted flies. Throughout the season, most (>90%) of the captured flies were sexually mature and of high egg load (>17 eggs per female). Implications of these findings for control of R. pomonella in orchards using baited red spheres are discussed.