Synthetic sex pheromone of the pea mothCydia nigricana, (E,E)-8,10-dodecadien-1-yl acetate (E8,E10-12: Ac), was applied in polyethylene dispensers at a rate of 30 g/ha and 600 dispensers/ha in a 0.6-ha pea field. The release rate ofE8,E10-12: Ac was 140 mg/ha/day after six days, and 82 mg/ha/day after 20 days. Aerial concentrations ofE8,E10-12: Ac, as measured by a portable EAG apparatus, ranged from 2 ± 2 to 7 ± 3 ng/m(3). The antennal signal was high and rather constant within pea canopy, but was lower and fluctuated strongly above canopy. Initially, >99% isomerically pureE8,E10-12: Ac was released, and male moths were attracted to dispensers. After nine days, isomeric blend composition had equilibrated to approx. 92%E8,E10-12: Ac and 8% of the inhibitory isomersE,Z-,Z,E-, andZ8,Z10-12: Ac. Males were then repelled from the pheromone-permeated field. Traps baited with 100 µgE8,E10-12: Ac caught 258 ± 133C. nigricana males/trap in the control, but no males at all in the disruption field.