THIS STUDY was carried out to evaluate the potential effect of water-soluble (WE) and ethanol (EE) extracts obtained from macroalgae Ulva fasciata (UF) and Enteromorpha flexuosa (EF) on Cercospora beticola growth, conidial germination, disease severity, and sugar beet yield and its impact on the activity of resistance related enzymes (peroxidase and chitinase). Pseudomonas fluorescens (Ps-20) and P. putida (Ps-15) were also tested and compared with the recommended opus fungicide as well as the unsprayed treatment. All treatments noticeably inhibited the fungal growth (47.7-85.7% efficacy) and reduced the percentage of germinated spores (90% in control and 5.0-18.3% in bioagent treatments) in vitro. With foliar application in Damietta and Kafr El-Sheikh, the range of C. beticola spots number (SN) per 5 leaves (5L), spot area (SA), and disease severity (DS) was remarkably reduced (53.2-194.8 SN/5L, 1.0-2.7 mm2, and 1.3-9.3%, respectively) compared with the untreated control (1399.7-1773.7 SN/5L, 7.5-11.1 mm2, and 25.0-38.3%, respectively). Also, root weight and sucrose percentage (%) were significantly enhanced when the bioagents were sprayed on leaves in the two field trials. Additionally, foliar application with E. flexuosa crude extract (EE-EF), P. fluorescens (Ps-20), and P. putida (Ps-21) significantly increased chitinase but not peroxidase activity in leaves compared with the control in the two governorates. Accordingly, foliar application of these eco-friendly bioagents may be useful for decreasing both the disease and the use of environmentally polluting chemical fungicides.