Agrotis ipsilon (Hufnagel) (Lepidoptera: Noctuidae) is considered one of the most destructive pests worldwide. It attacks most agriculture crops, causing high yield loss due to its nutrition on roots. So, management of this pest is essential, especially with other new methods of management, this is because of the disadvantages and risks of chemical insecticides. Ozon (O₃) is one of the alternative methods for pest management which is caused by non-thermal atmospheric pressure plasma created by dielectric barrier discharge (APPD) and oxygen gas fed into an ozone generator. Ozon application is becoming more popular, especially because it doesn't leave any residue and doesn't require aeration to exclude the gas. In this study, four ozone concentrations were applied to larvae and pupae of A. ipsilon to detect larval mortality and follow the remaining live larvae and pupae until the end of the pest life. The concentrations were, 250, 500, 1000 & 1500 ppmv for 15 min. The results proved the effectiveness of ozone on larvae from both mortality and denaturation of the rest larvae after seven days of the beginning of the experiment. The mortality rate increases with increasing ozone concentration. As soon as all treated pupae couldn't emerge the adult, caused different malformations and failure of emerging moths.