The availability of important nutrients such as calcium and nitrogen during the growing period can have physiological effects on the plant that have been shown to play an important role in the postharvest quality and storage life of fruits and vegetables.Both calcium and nitrogen have been reported to have substantial effects on the resistance of fruits and vegetables to pathogens.Increasing the level of calcium in plant tissue has been shown to increase resistance to pathogens,probably due to its role in the structure of the cell wall and membranes.