Rate of release of spruce budworm pheromone from virgin females and synthetic lures.

The rate of pheromone [(E)- and (Z)-11-tetradecenal] release from calling virginChoristoneura fumiferana females and synthetic lures was determined in both static and aerated atmospheres. In a static system ca. 2 ng/hr was recovered per female. Owing to the > 75% adsorption onto the females' bodies in static atmospheres, the actual release rate has to be corrected to roughly 9-27 ng/hr, depending on the percentage adsorbed. In the air-flow system, females were found to release between 4 and 20 ng/hr. On a 16∶8 light-dark cycle, calling began 1-2 hr before lights-off and continued nonstop until lights-on. Pheromone was emitted throughout calling, while no pheromone was detected during the noncalling periods.