Field studies of synthetic food-based attractants for detecting invasive fruit flies (Diptera: Tephritidae)

True fruit fly species (Diptera: Tephritidae) threaten the production and international trade of many fruit and vegetable crops. Many fruit fly-free regions operate trapping programs for the detection of these invasive pests, and food baits are an important component of detection trapping. A torula yeast-borax (TYB) solution has been widely used as a food bait, but it has a relatively short field longevity and is generally replaced every 1–2 weeks. Dry synthetic food-based attractants, consisting of ammonium acetate, putrescine, and trimethylamine, have been developed and appear to be effective for several months. Initially, the three components were presented in individual sachets within a trap, but to ease handling ‘all-in-one’ dispensers have been developed that contain all three components. While a logistical improvement, there are few data that compare captures between the standard TYB solution and these combination dispensers. This study presents the results of field experiments assessing the relative effectiveness of three ‘all-in-one’ dispensers of synthetic food-based attractants (i.e., Scentry food cones, Suterra Unipaks, and Susbin Difusors) in trapping three major pest species of tephritid fruit flies in Hawaii. The data presented here indicate that, with respect to C. capitata, the Difusor lures performed as well as TYB, while the Unipaks and food cones were significantly less attractive than TYB. With respect to B. dorsalis and Z. cucurbitae, none of the synthetic baits tested was as effective as TYB. Thus, among the baits studied here, TYB was most effective in attracting all three of the target species.