The female sex pheromone of the peach leafminer, Lyonetia clerkella Linne (Lepidoptera:Lyonetiidae), was analyzed by coupled gas chromatographic-electroantennographic detector (GC-EAD). GC-EAD analyses of pheromone gland extract revealed a single compound that elicited responses from male antennae. Retention time on DB-l column of EAD-active compound was identical to that of syn-thetic (14S)-14-Methyl-1-octadecene (14Sme-1-18Hy). In field tests, sticky traps baited with synthetic l4Sme-1-18Hy alone were highly attractive to male. Traps with 0.1 ㎎ dose showed the lowest catches, but there were no significant difference in the numbers of moth caught in traps baited with doses of 0.5 and 1.0 ㎎. The results of the field assays for longevity of pheromone traps showed that effectiveness of lures maintained for at least 8 weeks under field condition. The attractiveness of 14Sme-1-18Hy was not affected by the addition of butylated hydroxytoluene (BHT) in lures as an antioxidant. Traps baited with 0.5 ㎎ 14Sme-l-18Hy were successfully used to monitor L. clerkella male flights. Analysis of seasonal trap catches over two years showed that moth flight activity in peach orchards occurred over a period of seven months with six generations in Suwon.