Temporal and Spatial Patterns of Sweetpotato Weevil (Coleoptera: Curculionidae) Counts in Pheromone-Baited Traps in White-Fleshed Sweet Potato Fields in Southern Florida

Abstract

Studies were conducted to determine the potential of a synthetic sex pheromone that attracts only males for monitoring sweet potato weevil, Cylas formicarius elegantulus (Summers), populations in southern Florida. Mean weevil counts in plastic funnel traps baited with 10 μg of pheromone and placed in different commercial plantings of white-fleshed sweet potato, Ipomoea batatas (L.) Lam. cv. Picadito, ranged between 2 and 5,785 males per trap per night. Temporal patterns of weevil counts were cyclical, probably because of emergence of new weevil generations following monthly insecticide applications. Mean weevil counts in volunteer fields ranged between 27 and 4,413 per trap per night indicating that volunteer fields harbor dense weevil populations. Spatial statistics indicated that male populations were aggregated. The number of plastic funnel traps required to estimate weevil density reliably was too high to be practical at 10–15% precision levels, but was practical at a 25% precision level. Plastic funnel traps caught significantly more weevils (90–97% of the total catch) and were significantly more efficient (85% efficiency) at catching males than screen-cone boll weevil traps (3–10% of the total catch and 49% efficiency).