In Asian cuisines, the onion (Allium cepa L.) is an essential ingredient. However, one of the most significant challenges for onion cultivation is pest and disease control. The major constraints are fungal bulb rot by Fusarium spp., Pythium spp. Sclerotium spp. and Rhizoctonia solani, anthracnose disease or twister diseases by Colletotrichum spp., purple blotch disease by Alternaria poori, and bacterial bulb rot. There's also the issue of tip burning and secondary microbial infections to consider. The onion is water and fertilizer-sensitive crop. As a result, farmers follow a variety of fertilizer and water management schedules based on their climatic conditions. The use of gypsum as a fertilizer in terms of disease management and tip-burning issues was highlighted in this study. Mineral nutrition plays an important role in the control of several plant diseases. According to the findings of the study, gypsum plays a dominant role in enhancing growth and total bulb yield from the 50 kg/ha gypsum application as the basal fertilizer is followed by the 50 kg/ha application two weeks after planting is superior to all other treatments with the lowest disease conditions and no tip-burning problem. Although 50 kg/ha gypsum application has some tip-burning conditions, it also has no significant difference with the best treatment in terms of total yield and diseases conditions.