Evaluation of imidacloprid-treated traps as an attract and kill system for filth flies during contingency operations

Two field trials were conducted to evaluate if filth fly trap efficacy was increased by augmentation with an insecticide application to the trap's exterior. Four Fly Terminator Pro traps (Farnam Companies, Inc, Phoenix, AZ) baited with Terminator Fly Attractant (in water) were suspended on polyvinyl chloride pipe framing at a municipal waste transfer site in Clay County, Florida. The outer surfaces of 2 traps were treated with Maxforce Fly Spot Bait (Bayer Environmental Science, Research Triangle Park, NC) (10% imidacloprid) to compare kill rates between treated and untreated traps. Kill consisted of total flies collected from inside traps and from mesh nets suspended beneath all traps, both treated and untreated. Each of 2 treated and untreated traps was rotated through 4 trap sites every 24 hrs. In order to evaluate operational utility and conservation of supplies during remote contingency operations, fly attractant remained in traps for the duration of the first trial but was changed daily during the second trial (following manufacturer's recommendations). In addition, ½ strength Terminator Fly Attractant was used during the first trial and traps were set at full strength during the second trial. Flies collected within the traps and in mesh netting were counted and identified. Three species, Musca domestica (L.), Chrysomya megacephala (F.), and Lucilia cuprina (Wiedemann), comprised the majority of samples in both trials. The net samples recovered more flies when the outer surface was treated with imidacloprid, however, treated traps collected fewer flies inside the trap than did untreated traps for both trials. No significant statistical advantage was found in treating Fly Terminator Pro trap exteriors with Maxforce Fly Spot Bait. However, reducing manufacturer's recommended strength of Terminator Fly Attractant showed similar results to traps set at full strength. Treating the outer surfaces may improve kill of fly species that do not enter the trap. Terminator Fly Attractant was also found to be more effective if traps were not changed daily and left to hold dead flies for longer periods.