Bait Stations for the Suppression of Screwworm Populations

Bait stations were prepared and evaluated for field effectiveness against Cochliomyia hominivorax (Coquerel). Each bait station consisted of a paper cone (15 cm diameter) covered on top with ca. 50 g of feeding bait-toxicant mixture (dried blood, sugar, Elmer’s® glue, dichlorvos) suspended over a cup of solidified swormlure-2 (75% swormlure-2, 25% American Hoetsch KSL wax). In the initial field evaluation, bait stations were equal in effectiveness to wind-oriented traps for killing or capturing screwworms, and were six times more effective against secondary screwworms, C. macellaria (F). Chemical assays indicated that bait stations should attract and kill screwworm flies for 45 to 60 days. In two other field tests, the toxicant in the bait stations was replaced with sodium fluorescein dye. In the first test, bait stations were placed in groups of four near livestock watering areas (mostly windmills); 18% of the screwworms and 20% of the secondary screwworms captured on the ranch during the 30-day test period were dye marked. In the second test, bait stations were placed randomly over the ranch; ca. 25% of the screwworms and 31% of the secondary screwworms captured were dye marked.