Components of the sex pheromone of the currant pug moth, Eupithecia assimilata, a re-emergent hop pest in UK.

After an absence of 50 years, the currant pug moth, Eupithecia assimilata Doubleday (Lepidoptera: Geometridae), has reappeared as an important pest of hops, Humulus lupulus L. (Cannabaceae), in the UK. Pheromone gland extracts from virgin female E. assimilata moths were shown to contain (3 Z,6 Z)- cis-9,10-epoxyheneicosadiene (3 Z,6 Z- cis-9,10-epoxy-21:H) by gas chromatography linked to mass spectrometry. (3 Z,6 Z,9 Z)-heneicosatriene (3 Z,6 Z,9 Z-21:H) was also found as a minor component in one of two extracts. In field experiments, significant numbers of male E. assimilata moths were caught in traps baited with the (9 S,10 R)-enantiomer of 3 Z,6 Z- cis-9,10-epoxy-21:H but not in those baited with the (9 R,10 S)-enantiomer or racemic mixture. Addition of 3 Z,6 Z,9 Z-21:H at the ratio present in gland extracts greatly reduced the attractiveness of the epoxydiene. [ABSTRACT FROM AUTHOR]