It is a noninfectious disease caused by low levels of calcium in tomato fruit and is not associated with soil contact or with damage to other plant parts. Blossom end rot occurs frequently where large fluctuations in soil moisture are allowed to occur. Symptoms Symptoms first appear as small, light brown or watersoaked spots at the blossom end of immature fruit.
Lesions are generally dry and can be as large as the diameter of the tomato fruit.
A soft, wet rot will develop after affected areas of fruit are invaded by decay fungi and bacteria. Internal hardening, discoloration, and tissue collapse may be present without the characteristic external symptoms of blossom end rot. Typical lesions on blossom end of tomato fruit. Although blossom end rot is the result of a calcium deficiency in fruit, environmental conditions that interfere with uptake and availability of water and nutrients can contribute greatly to symptom expression. Excessive nitrogen fertilizer also can contribute to blossom end rot by promoting vigorous vine growth and depleting available calcium in the soil.