Trapping studies were conducted in a large field cage and in the field as part of a coordinated effort to develop a formulation that would control the release of grandlure, the synthetic pheromone ofAnthonomus grandisBoheman. From these and related studies, two new formulations were developed that controlled the release of this pheromone. These formulations were evaluated extensively at several locations and found to be effective for a least two weeks, during which period they were more attractive than either caged male boll weevils or current formulations. Evidence presented shows clearly that attractiveness of any grandlure fonnulation is influenced by the dose and relative proportions of the four components of the pheromone.