Abstract
Cercospora leaf spot (CLS), caused by Cercospora beticola, is a severe threat to sugar beet (Beta vulgaris) production in Egypt's Nile Delta and poses resistance and ecological problems to synthetic fungicides. This study investigates Alhagi maurorum (camelthorn), an endemic medicinal shrub of arid regions, and evaluates it as a sustainable plant-sourced biofungicide for integrated CLS management. Following molecular confirmation of C. beticola (PCR amplified actin gene, 959 bp; ITS region sequenced and deposited in GenBank under accession PX884367), A. maurorum ethanolic extract (GC-MS) profiling of the ethyl iso-allocholate (1.39%), squalene (7.81%), and methyl oleate (27.33%) was determined as the antifungal constituents from GC-MS profiling. Molecular docking highlighted ethyl iso-allocholate's dual inhibition of CYP51 (- 8.4 kcal/mol) and CHS (- 6.5 kcal/mol), critical for fungal ergosterol biosynthesis and cell wall integrity. In vitro assays demonstrated complete fungal suppression at 10% extract concentration, mirroring the synthetic fungicide Score®. The efficacy of the extract in controlling disease (66.4-71.5% disease control), along with increased root yield (34.23 tons/fed) and sucrose purity (91.81-92.38%) in two-season field trials, was validated in CLS endemic Kafr EL Sheikh. The biochemical analyses of treated plants showed elevated antioxidant defenses, reflected in phenolics (184.43-186.73 mg/g) and superoxide dismutase (SOD: 122.10-123.77 U/g), to protect the plants against oxidative stress. As an eco-friendly alternative to synthetic fungicides, the extract has biodegradability, pharmacokinetic suitability, and multi-target action. By bridging phytochemistry, computational biology, and field agronomy, this work advances integrated, climate-resilient strategies for CLS management and underscores the potential of arid-adapted plants in sustainable agriculture. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12298-026-01728-0.