ATTRACTION OF PEA MOTH CYDIA-NIGRICANA F (LEPIDOPTERA, TORTRICIDAE) TO FEMALE SEX-PHEROMONE (E,E)-8,10-DODECADIEN-1-YL ACETATE, IS INHIBITED BY GEOMETRIC ISOMERS E,Z, Z,E, AND Z,Z

Field attraction of Cydia nigricana males to synthetic female sex pheromone (E,E)-8,10-dodecadien-1-yl acetate, formulated on red rubber septa, declined continuously during two weeks. This was due to isomerization of (E,E)-8, 10-dodecadien-1-yl acetate: eight days after application of purified E,E isomer, the proportion of E,Z; Z,E; and Z,Z isomers in rubber septa aged in the laboratory was 4 %; a 5 % addition of any one of these isomers to fresh lures of (E,E)-8, 10-dodecadien-1-yl acetate significantly reduced male attraction. Stereospecific syntheses of (E,Z)-, (Z,E)-, and (Z,Z)-g, 10-dodecadien-1-yl acetate are described. The pheromone gland of Cydia nigricana contains 0.8 ng/female of (E,E)-8,10-dodecadien-1-yl acetate, accompanied by three monounsaturated acetates, (E)-9-dodecen-1-yl acetate, (Z)-5-tetradecen-1-yl acetate, and (Z)-7-tetradecen-1-yl acetate (0.1 ng/female each). These compounds did not augment male trap catch when added to (E,E)-8,10-dodecadien-1-yl acetate.