Analysis of sex pheromone gland extract of the citrus flower moth, Prays nephelomima (Lepidoptera: Yponomeutidae) by coupled gas chromatography-electroantennogram detection, revealed one electrophysiologically active compound. Structural analysis using gas chromatography, gas chromatography-mass spectrometry, and dimethyldisulfide derivatization identified this as the monounsaturated aldehyde (Z)-7-tetradecenal. Field trials in commercial citrus orchards on the North Island of New Zealand showed that (Z)-7-tetradecenal was highly attractive to male P. nephelomima. Phenology data, collected over 19 months in three commercial orchards, from traps baited with the sex pheromone at a lure loading of 300 microg on a red rubber septum, indicated that male moths may be present throughout the year, with numbers peaking in late summer and autumn.