Tomato Disorders


Blossom End Rot

Found worldwide

Damage Symptoms

Light tan lesions turn to dark brown sunken areas at the blossom end of fruit. The lesions enlarge and become more sunken and leathery, accompanied by dry rot. A black mold may grow on the surface of the lesion.


Conditions for Development

Blossom End Rot is caused by a calcium deficiency. Conditions that reduce calcium uptake by tomato plants include moisture fluctuations, excessive soil salinity, the use of ammonia nitrogen, excessive nitrogen fertilization, high relative humidity, and root damage.


Control

Use cultivars that are more tolerant to this disorder. If needed, apply lime or calcium fertilizers before planting. Irrigate during dry weather and/or use mulch to provide a constant moisture supply to the plant. Cultivate carefully to reduce root damage. Avoid excessive use of nitrogen, especially in the ammonium form. Avoid fields that are difficult to irrigate uniformly or those with high salinity.