Two field trials were conducted at Mallawy Agric. Res., Station, El-Minia Governorate, Egypt, during 2017/2018 Two field trials were conducted at the experimental farm of Malawi Agricultural Research Station, El-Minia Governorate, Egypt, during 2018/2019 and 2019/2020 seasons to study the effect of three sowing dates (the 15^th of September, October and November) under three irrigations number [eight, nine and seven irrigations] and their effects on root-rot disease, yield and quality of three sugar beet varieties (Farida, Panther and Gazil). A split -split plot design was used. The results indicated that sowing sugar beet on 15^th Sept. significantly reduced root rot disease incidence and increased root traits (length, diameter and fresh weight), sucrose %, root and sugar yields/fed and recorded lower contents of impurities, compared to the others two sowing dates in both seasons. Sowing beet plants on 15^th Nov. gave the highest phenolic compounds in both seasons. Decreasing irrigations number up to seven times significantly reduced disease severity% in both seasons. Irrigating sugar beet plants nine times significantly achieved the heavier roots and root yield compared to the other two irrigations in both seasons. Applying eight times of irrigation recorded the maximum phenolic compounds, sugar yield, and sucrose % compared to the less or a greater number of irrigations in both seasons. The combined analysis of variance and AMMI analysis of Farida cv. recorded the lowest response of root-rot severity % when applying seven times of irrigation at the first date of sowing (15th Sept.) and Ghazil cv. recorded the highest response to applying nine times of irrigation in the last date of sowing (15th Nov).