The oriental tobacco budworm, Helicoverpa assulta (Guenee) is a major pest of red pepper in Korea. Insecticide spray is a prevalent control tactic in most farms, but an effective control is difficult because the larvae are protected inside the fruit. Objective of this study was to investigate the seasonal occurrence of the male moths using pheromone trap and to evaluate the control efficacy of insecticide applications based on the trap catch data at red pepper fields in Suwon. The results of pheromone trap catch during three years showed that the moth flight activity occurred from late May to early October. Peak periods of the adult flight, which are indicators of each generation, occurred in late June, late July-early August, and late August-early September. Trap catches during the overwintering and first adult generation were closely linked with subsequent damage. Although the trap catch during the second generation was higher than the previous generations, damage level caused by this generation larvae was low. Experiment results revealed that fruit damage by H. assulta could be effectively reduced by five sprays of insecticides based on the trap catch data throughout the season.