Comparative assessment of different traps performance for capturing the New World screwworm fly

The New World screwworm fly, Cochliomyia hominivorax, represents a major threat to livestock production in several regions of the Americas. The objective of this study was to evaluate the effectiveness of three trap types for C. hominivorax surveillance. The study was conducted in Uruguay (32° S), in area with a known natural presence of C. hominivorax. NZI, NZI-M (a modified version designed to optimize capture efficiency), and vertical sticky traps (VST) were used, all baited with baited with Swormlure-4 (SL-4). A Latin square design was applied, testing each trap at four sampling sites (forest edge, near watercourses, pastureland, and near livestock corrals), rotating twice through each site over three consecutive days. This design was repeated across the four seasons of the year. Sampling points were separated by more than 1,200 m to ensure independence of captures. A total of 96 blowflies (Calliphoridae) were collected, of which 15 were identified as C. hominivorax (15.6%). Seven, five, and three screwworm flies were captured using NZI, NZI-M, and VST traps, respectively. C. hominivorax was captured during autumn (11/15) and summer (4/15), with no differences among sampling sites. The NZI and NZI-M traps baited with SL-4 showed potential as effective tools for C. hominivorax surveillance in comparison of VST trap, allowing the recovery of well-preserved specimens suitable for taxonomic and molecular identification.