Male Lures and the Detection of Bactrocera Fruit Flies (Diptera: Tephritidae): Performance of Solid Dispensers with Separate Insecticidal Strips Relative to Standard Liquid Lures

摘要

Detection of pestiferous Bactrocera fruit flies (Diptera: Tephritidae) relies largely on deployment of traps baited with male-specific attractants. Two species in particular, B. dorsalis (Hendel) and B. cucurbitae (Coquillett), pose seri- ous threats to US agriculture, and males of these species are attracted to methyl eugenol (ME) and cue lure (CL), respectively. At present, these lures are applied as liquids (with naled added as an insecticide) to cotton wicks placed inside Jackson traps, a procedure that entails considerable handling time and potential health risk owing to inadvertent contact with the chemicals. Recent studies have demonstrated that solid dispensers containing male lures and the toxicant DDVP (dichlorvos) capture as many or more B. dorsalis and B. cucurbitae males as the standard liquid formulation. Owing to registration requirements, deployment of solid dispensers requires the lure and the killing agent be presented in separate devices. The goal of this study was to compare capture of Bactrocera males between traps baited with the liquid formulation (lure and naled mixed) versus traps baited with solid lure-bearing plugs or wafers and separate DDVP strips (lure and DDVP separate). Field trapping was conducted in various areas of Oahu, Hawaii, using variable amounts of DDVP (0.09 – 0.295 g) in the traps with the solid dispensers. In gen- eral, for both B. cucurbitae and B. dorsalis, traps with wafers performed as well as traps with liquids regardless of lure age (fresh or aged 6 weeks), DDVP dose, test location, or lure presentation (ME and CL presented singly or combined). Traps with aged plugs also performed as well as aged liquids for both Bactrocera species under nearly all test conditions. However, in a large proportion of tests, fresh plugs captured significantly fewer males of both species than fresh liquids over the full range of DDVP doses tested. The implications of these findings for Bactrocera detection are discussed.