Sex pheromone of the fall armyworm Spodoptera frugiperda (Lepidoptera: Noctuidae) of a "far east" population from Okinawa, Japan.
Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) is native to the Americas and has recently invaded Okinawa, Japan via Africa, South Asia and China. Gas chromatography/mass spectrometry analyses of hexane extracts of 100 abdominal glands of Okinawan females revealed six candidate compounds for sex pheromone, (Z)-9-tetradecenyl acetate (Z9-14:Ac, ca. 6 ng/female), (Z)-11-hexadecenyl acetate, (Z)-11-tetradecenyl acetate, (Z)-7-dodecenyl acetate (Z7-12:Ac), (E)-9-dodecenyl acetate, and (Z)-9-tetradecen-1-ol at the ratio of 100:10:1.3:0.90:0.13:1.8, respectively. In Okinawa, only small numbers of males were captured with the original blend of these compounds. However, much more males were attracted to a 100:3 blend of Z9-14:Ac and Z7-12:Ac that had been suggested by others to be the most effective blend in a Florida population. In another test in Okinawa, even more males were captured with a 100:1 blend of these compounds than with a 100:3 blend. Significant numbers of males of other moths, Mythimna loreyi (Duponchel) and Chrysodeixis eriosoma (Doubleday), were also attracted to blends of Z9-14:Ac and Z7-12:Ac when the ratio of the latter to the former compound was increased from 100:1 to 100:10. Based on these results we concluded that the most powerful as well as convenient sex pheromone formulation to monitor S. frugiperda populations in Okinawa was a 100:1 blend of Z9-14:Ac and Z7-12:Ac.