Presence and positioning of insecticidal strips in Jackson traps affect catch of oriental fruit flies and melon flies (Diptera: Tephritidae).

Many countries operate trapping programs to detect incursions of pestiferous fruit flies (Diptera: Tephritidae). Three male-specific attractants form the cornerstone of these surveillance networks: methyl eugenol for Bactrocera species, cue-lure for Bactrocera and Zeugodacus species, and trimedlure for Ceratitis species. Traditionally, these lures were applied as a liquid to a cotton wick, but polymeric plugs are being used more widely. Regulations require that any toxicant placed in a trap with a lure-bearing plug must be presented separately from the plug, which, most commonly, is held in a plastic, perforated basket inside a Jackson trap. The present study examined whether the presence or position of an insecticidal DDVP (dichlorvos) strip within a Jackson trap affects capture of Bactrocera dorsalis, Zeugodacus cucurbitae, and Ceratitis capitata males. Captures were compared among (i) traps without a DDVP strip, (ii) traps with a DDVP strip placed in a separate basket from the lure-bearing plug, and (iii) traps with a DDVP strip placed in the same basket as the plug. Results were similar for B. dorsalis and Z. cucurbitae: traps with the toxicant in the same basket as the male-lure plug captured significantly more males than traps with the toxicant in a separate basket. For B. dorsalis, traps with the toxicant in a separate basket from the lure-bearing plug had significantly higher captures than traps lacking a toxicant, while results for Z. cucurbitae were inconsistent between study sites. Neither the presence nor position of DDVP strips in Jackson traps influenced captures of C. capitata males.