Identification of the sex pheromone secreted by Synanthedon hector (Lepidoptera: Sesiidae)

Abstract

The Japanese cherry treeborer, Synanthedon hector (Lepidoptera: Sesiidae), is a harmful pest of Prunus trees. After male attraction using a 50 : 50 mixture of (3Z,13Z)- and (3E,13Z)-3,13-octadecadienyl acetates (I and II) was determined, a mating disruptant formulated with the two compounds was developed and commercialized; however, the sex pheromone secreted by S. hector females has not been characterized. Analyses of a pheromone gland extract using gas chromatography (GC) equipped with an electroantennographic detector and GC combined with mass spectrometry showed that virgin females produced two 3,13-dienes, I and II, in addition to (2E,13Z)-2,13-octadecadienyl acetate (III). The ratio of the three components (I : II : III) was about 60 : 36 : 4. In the field, S. hector males were effectively attracted by a lure baited with a mixture of I and II at a ratio of 70 : 30-30 : 70, and III showed neither synergistic nor inhibitory effects on the attraction. Further experiments with other geometrical isomers of the 3,13-dienes indicated that male moths strictly discriminated the configurations of the two double bonds. Mixtures combining one insect-produced isomer (I or II) and other unnatural isomers attracted few males in the field.