Combining Cue-Lure and Methyl Eugenol in Traps Significantly Decreases Catches of Most Bactrocera, Zeugodacus and Dacus Species (Diptera: Tephritidae: Dacinae) in Australia and Papua New Guinea

Abstract

Male fruit fly attractants, cue-lure (CL) and methyl eugenol (ME), are important in the monitoring and control of pest fruit fly species. Species respond to CL or ME but not both, and there are conflicting reports on whether combining CL (or its hydroxy analogue raspberry ketone) and ME decreases their attractiveness to different species. Fruit fly monitoring programs expend significant effort using separate CL and ME traps and avoiding lure cross-contamination, and combining the two lures in one trap would create substantial savings. To determine if combining lures has an inhibitory effect on trap catch, CL and ME wicks placed in the same Steiner trap were field tested in comparison to CL alone and ME alone in Australia and Papua New Guinea (PNG). In Australia, 24 out of 27 species trapped were significantly more attracted to CL or ME alone than the combination ME/CL lure, including the pests Bactrocera bryoniae (Tryon), B. frauenfeldi (Schiner), B. kraussi (Hardy), B. neohumeralis (Hardy), B. tryoni (Froggatt) (CL-responsive), and B. musae (Tryon) (ME-responsive). In PNG, 13 out of 16 species trapped were significantly more attracted to CL or ME alone than the ME/CL combination, including the pests B. bryoniae, B. frauenfeldi, B. neohumeralis, B. trivialis (Drew), Zeugodacus cucurbitae (Coquillett) (CL-responsive) and B. dorsalis (Hendel), B. musae, and B. umbrosa (Fabricius) (ME-responsive). This study shows that combining CL and ME in the one trap in equal parts significantly reduces catches of most species of Dacini fruit flies in Australia and PNG.