This study was conducted during the two seasons (2016-2017 and 2017-2018) at the Horticulture Department, Faculty of Agriculture, Benha University, Qalyubya Governorate, Egypt, to examine the effects of salicylic acid, ascorbic acid, and oxalic acid (at concentrations of 2, 4, and 8 mM) against Sclerotium rolfsii (syn. Athelia rolfsii) and for enhancing the growth and chemical constituents of Hippeastrum vittatum. The results showed that all treatments significantly increased all measured parameters in both seasons. All tested chemical antioxidants reduced the linear growth of S. rolfsii in vitro in both seasons. Salicylic acid was the most effective at high concentrations, with a mean linear growth of 29.1 mm, representing an average growth inhibition of 67.6%. Under field conditions, antioxidant treatments significantly reduced the bulb rot percentage. Salicylic acid treatments were the most effective, reducing the disease incidence to 22.7% and 21.9%, respectively. Total genomic DNA from fungal sclerotia isolates was analyzed by PCR using primers specific to the coding region of the SCR intergenic region. DNA amplification analysis of samples collected from four different Governorates in Egypt (Qalyubia, Beheira, Giza, and Menoufia) demonstrated the detection of a 540 bp DNA fragment PCR analysis using SCR-specific primers confirmed the identification of the fungal isolates from the all Governorates, generating the expected ~540 bp amplification fragment , which is consistent with specific detection of S. rolfsii. Finally, from previous studies, the fungal pathogen as S. rolfsii was the causal agent of bulb rot of amaryllis in Northern Thailand.