Nanotechnology is the design, character, creation and use of structures, materials and systems by controlling their shape and size at the nanometer scale. The main focus of this research is nanoscale materials and how they are used for various purposes in agriculture. Nanotechnology will become a new branch of science covering disciplines such as physics, chemistry, biology, information science and medicine in the coming years. In these systems, various metal nanoparticles such as silver, gold, zinc and iron are used in the prevention and treatment of plant diseases. Among various metal nanoparticles, silver nanoparticles are the most widely used. Silver nanoparticles exhibit unique physical and chemical properties compared to their macroscopic counterparts. Biosynthesized silver nanoparticles are more important than chemical synthesis because they are safe and do not produce toxic byproducts. More than 30 fungal diseases are known to cause disease in cocoa cultivation, of which Phytophthora spp., Moniliophthora perniciosa and Moniliophthora roreri are the most serious, and can cause commercial losses in crop cultivation. To date, there are no effective controls to control fungal diseases in cocoa. Therefore, it is possible to use biosynthesized silver nanoparticles for the management of major fungal diseases in cocoa.