Sugar beet, Beta Vulgaris L. is a strategic crop of sugar industry in Egypt. Sugar-beet fly, Pegomyia mixta Vill. (Diptera: Anthomyiidae), is considered to be the most serious insect pest attacking sugar-beet all over the world. The intensive use of chemical insecticides led to suppress the role of parasitoids in sugar beet fields. Thus, this work was undertaken at the experimental farm of Sakha Agricultural Research Station – kafr Elsheikh Governorate during two successive seasons 2019/ 2020 and 2020/ 2021, to examine the influence of agricultural and biological control methos in reducing populations of P. mixta. Results proved that the third plantation date had the highest populations of P. mixta larvae compared with the first and second plantation dates during the two seasons of the study. As far as we know, the larval-pupal parasitoid, Nasonia vitripennis (Walker) is identified for the first time from P. mixta larvae in Egyptian sugar beet fields. Percentages of larval parasitism of P. mixta that caused by N. vitripennis were 38.23, 36.76 and 35.77% in the first, second, and third plantation dates, respectively in 2019/2020 season. While, they were were 48.27, 56.94 and 32.74%, respectively in 2020/2021 season. In Integrated Pest Management programs, N.vitripennis and sowing dates might be taken in consideration for reducing populations of P. mixta.