Mating disruption treatments for the Chinese tortrix Cydia trasias (Meyrick) with synthetic sex pheromone were tested on a shade-tree, the Chinese scholar-tree (Sophora japonica L.), in Beijing, China, in 1999. Two test sites were treated three times each during the beginning of overwintering flight period, and during the first- and second-generation flight periods. Each tree was treated with six dispensers releasing the C. trasias sex pheromone (0.5 mg load per dispenser). Treatments were evaluated by petiole and seed pod injuries and by captures of males in traps baited with live virgin females or synthetic sex pheromone lures. A 2:3 two-component blend of E8,E10-dodecadien-1-ol (E8,E10–12:OH) and E8,E10-dodecadienyl acetate (E8,E10–12:Ac) was used for mating disruption. At site I, catches of males in female-baited traps were reduced by 100, 99.1, and 98.2% when compared with control plots, and catches in pheromone-baited traps were reduced by 98.2, 95.7, and 93.6%, during the three periods of moth flight, respectively. Also at site I, the tunneled petioles (first- and second-generation larval injury) were reduced by 68.1 and 60.6%, and the bored seed pods (third-generation larval injury) were reduced by 70.0%, for the first, second, and third larval generations, respectively, when compared with control plots. At site II, the bored seed pods in the treated plots were reduced by 89.5%, during the third period of larval injury. We conclude that mating disruption is promising as an effective control against C. trasias on shade-trees planted along streets.