Three slow-release preparations of grandlure, the synthetic pheromone ofAntonomus grandisBoheman, were evaluated in the field at 3 locations in Texas and Mississippi, to compare their relative attractancy to adult weevils during the period of fall dispersal. All 3 formulations, at both low (3 mg per unit) and high (12 mg per unit) doses of grandlure, were more attractive throughout 14-day test periods than were caged males or fast-release formulations that were both replaced at 2-day intervals. The combined results of field tests at all locations, and of laboratory analyses of weathered samples, suggested that a physical-barrier system might yield more consistent results, but no single formulation was decidedly superior to the others. Tests demonstrated also that slow-release formulations could be used effectively in the different types of boll weevil traps currently in use.