The attractiveness of grandlure and monoterpene volatiles from flower buds of select cottons, to boll weevils, was measured in the field. Significantly more boll weevils were attracted with 10 pl than with either 1 or 100 pl of the synthetic formulation representing monoterpene ratios found for flower buds of 'CAMD-E'. Greater numbers of weevils were attracted with 'STV-213 GL' than with 'CAMD-E' or STV-213 gl (glandless) synthetic formulations when traps were placed in a competitive trapping pattern. The attractiveness of grandlure to boll weevils was synergized with the synthetic monoterpene formulations.