Edema is a type of swelling in plants caused by the accumulation of water in the intercellular spaces. It is a common symptom of plant diseases and can be caused by a variety of factors, including nutrient deficiencies, environmental stress, and fungal or bacterial infections. EDEMA can also be caused by physical damage to the plant, such as hail or frost. In some cases, EDEMA can be beneficial, as it can help protect the plant from further damage.