A Trap for Monitoring the Sweetpotato Weevil (Coleoptera: Curculionidae) Using Pheromone or Live Females as Bait1

Abstract

A trap is described for surveying or monitoring the sweetpotato weevil, Cylas formicarius elegantulus (Summers), using virgin females or pheromone loaded onto rubber septa as bait. A dose-response in numbers of males captured was observed when rubber septa were baited with 10 ng, 100 ng, 1 μg, or 10 μg of pheromone. Traps baited with 100 ng or 10 μg caught more males than ones baited with one or three females which in turn caught more males than did light traps. Pheromone-baited traps caught males throughout the day and night, whereas light traps and those baited with females caught males only during the night. When traps were baited with 100 ng or 10 μg, >;90% of the males that came into contact with the trap were caught. When the opening to the trap was approximately the same height as the canopy of the sweet potato plants, traps baited with 10 μg captured more males than when the opening was either below or several centimeters above the canopy. The number of males caught per week followed an exponential curve for 22 weeks after sweet potato slips were planted.