A series of ester and ether derivatives of (E,E)-8,10-dodecadien-1-ol (8,10-D), the sex pheromone of the codling moth,Laspeyresia pornonella(L.), were impregnated on separate rubber sleeve stoppers and exposed in traps in the field to determine their ability to inhibit attraction of male codling moths. For each series of derivatives, the number of carbon atoms in a straight chain added to 8,10-D ranged from 1 to 4. When only one carbon atom was added, the derivatives were not significantly inhibitory. When 4 were added, the derivatives were moderately inhibitory. When 2 or 3 were added, the derivatives were potent inhibitors. Branching in the ether derivatives decreased the potency of the inhibitors.