Comparisons of standard and extended-life boll weevil (Coleoptera: Curculionidae) pheromone lures

The Southeastern Boll Weevil Eradication Program has proposed reducing maintenance program costs in eradicated zones by using an extended-life "superlure" in traps to detect populations of the boll weevil, Anthonomus grandis grandis Boheman. However, superlure effectiveness has not been extensively evaluated. We compared the superlure (30 mg of eugenol plus 25 mg of grandlure) to a standard lure (10 mg of grandlure) based on captures of weevils and changes in lure pheromone content. Lure treatments (standard and superlure, replaced biweekly or not replaced) were compared in 4-mo-long trapping periods. Captures of weevils did not generally reflect differences among lure treatments indicated by assays of lure contents. During the first 2 wk of exposure, amounts of pheromone released by the superlure were generally comparable with those of the standard lure, but pheromone composition was more stable. During the second 2 wk of exposure, the superlure usually released more pheromone than similarly aged standard lures, but less than half as much as the standard lure replaced biweekly. Based on numbers of captured weevils during the last 2 wk of an extended trapping period, the superlure performed similarly to the standard lure replaced biweekly. However, corresponding pheromone releases by the superlure were less than those by the standard lure replaced biweekly. This inconsistency suggests that numbers of captured weevils alone may be inadequate for evaluation of pheromone formulations. Our results suggest that better understanding of the consequences of reduced pheromone release during an extended trapping period is needed before adoption of the superlure can be recommended.