The Citrus Leafminer (CLM) larvae creates shallow tunnels in leaves of citrus (orange, mandarins, lemons, grapefruit, etc) and commonly attacks citrus young leaves. They spread almost worldwide (North America, Asia, Australia, etc) and difficult to control by chemicals due to their small size and their behavior of leaf rolling. Due to difficult of managing, our interest is preparing pheromone to control; Z7Z11-16;Al is known as the sex pheromone of this species in Japan. While blending Z7Z11-16;Al and Z7Z11E13-16;Al (3:1 ratio) is known as the pheromone of this insect in North America. Even though commercialized and mass produced already in overseas, there had been almost no report in Korea about synthetic studies and field screening results. The control of the regio-isomers is very important in this kind of pheromone synthesis. Our strategy is the regio-selective Wittig olefination reaction between E-pent-2-enyl(triphenylphsphonium)bromide (phosphonium salt) and the counterpart aldehyde using sodium hexamethyldisilazide (NaHMDS) as a base. All the spectroscopic data (1H, 13C, GC-Mass, etc) are nicely matched with the previously reported values. The field screening in the Jeju island is currently ongoing and will be reported.