【Objective】Cydia trasias is a shoot-boring pest severely damaging Ormosia hosiei seedlings in Longquan, Zhejiang Province. To date, there are few reports on biological characteristics of this insect in South China. In order to provide a basis for the scientific control of C. trasias, its biological characteristics, damage patterns, and chemical control efficacy were studied in present study. 【Method】The damage rate and larval densities across different tree ages (one-, two-, three-year container seedlings, 6-year plantation saplings) were investigated in field. Morphological features, life history, and behavioral traits of C. trasias were studied and recorded through laboratory rearing. Field trials were conducted with 8% cypermethrin microcapsule suspension and 1.8% abamectin emulsifiable concentrate at 1 500 × and 3 000 × dilutions to evaluate their efficacy against larvae. 【Result】C. trasias larvae bored hollow tunnels in shoots causing wilting. A single larva could infest three-five shoots. Larval density was significantly higher in six-year-old trees than that in younger seedlings (P < 0.05), but damage rate showed no age-related differences (P > 0.05). C. trasias produced four generations each year, and overwintered as mature larvae in tunnels in Longquan. Overwintered larvae pupated in early April; Adults emerged in late April. Larvae infested trees from May to November, and matured for overwintering by late November with the fourth generation. Adults were nocturnal, phototactic, and mated mainly between 18:00-19:30, laying eggs on tender shoots. Cypermethrin (1 500 × dilution is 90.06%; 3 000×dilution is 95.82%) and abamectin (1 500×dilution is 86.26%; 3 000 × dilution is 87.53%) significantly reduced larval density and damage (P < 0.001), with no efficacy difference between concentrations. 【Conclusion】C. trasias had four generations per year in Zhejiang Province, and the damage level was correlated closely with host age. Cypermethrin (1 500 × dilution) showed optimal field efficacy to control C. trasias. Our findings provide critical insights on monitoring and effective control of C. trasias.