Disease incidence and disease severity of date palm root rot were evaluated on cvs. Barhey, Majdol and Zaghloul during 2021 and 2022 growing seasons in different locations. The highest percentages of disease incidence and disease severity were recorded in nursery located at Beheira governorate, where the lowest were recorded from new orchards in Giza and Qaloubiya governorates during 2021. Isolation trials of the naturally infected date palm root rot yielded four fungal species identified as Fusarium solani, F. moniliforme, F. semitectum and Lasiodiplodia theobromae. Pathogenicity test showed that all isolated fungi were able to induce root rot on date palm seedlings. The highest average disease severity was obtained from the infection with F. solani, followed by F. moniliforme. While, little symptoms showed on the roots inoculated by F. semitectum. Zaghloul cultivar was more susceptible than Barhey and Majdol under artificial inoculation carried out during the two years of the investigation. Efficacy of Biocontrol T34 12% WP (Trichoderma asperellum strain T34), Serenade ASO 1.34% SC, Uniform 39 % SE, Hexaten and Tshgarin 30%SL was evaluated in vitro and under greenhouse conditions for controlling root rot of date palm seedlings. Complete reduction in colony growth of the most frequent fungi was observed due to using Uniform 39 % SE, followed by Hexaten and Tshgarin 30%SL. T34 and Serenade ASO 1.34% SC recorded the lowest efficacy. However, under greenhouse conditions Uniform, Tshgarin and Hexaten gave the highest efficacy for controlling date palm root rot on the two cultivars, Barhey and Zaghloul during the two seasons, while the lowest efficacy was recorded after treatment with T34 and Serenade ASO, respectively. The highest values of total phenol in the three tested date palm cultivars were observed in Barhey cv., while the lowest production were recorded in cv. Zaghloul. The highest values of total phenols was observed after using Uniform and Tshgarin, while the lowest levels of total phenols were recorded by using Serenade ASO. The highest values of polyphenoloxidase activity (PPO) were recorded in cv. Barhey. While the lowest were recorded in cv. Zaghloul. The highest values of PPO were observed after treatment with Tshgarin, while the lowest levels were obtained by using Serenade ASO.