Release of Grandlure, the pheromone of the boll weevil, Anthonomus grandis, from "matrix" and "reservoir" dispensers was investigated in terms of overall release rate and composition of the volatile blend released. Release from the Plato Industries PVC dispenser is first order, decreasing with age, but the composition of the volatiles released is reasonably constant during the lifetime of the dispenser and is the same as that of the blend in the dispenser. Release of Grandlure from polyethylene sachets is non-linear because the components are released at different rates and the composition of the volatiles released varies markedly during the lifetime of the dispenser. Significant decomposition is observed. PVC sachets show promise as dispensers for Grandlure which will release a blend of constant composition at a constant release rate.