Blossom End Rot

  • Symptoms

  • Trigger

  • Biological Control

  • Chemical Control

  • Preventive Measures

Blossom End Rot

blossom end rot

Deficiency


In a Nutshell

  • Brown or grey stains on the bottoms of green fruits.
  • Internal black rot might develop in fruits.
  • Fruits might not show external symptoms.

Hosts

Capsicum & Chili

Tomato

Symptoms

Blossom End Rot is characterized by the appearance of an irregular patch at the tip of the fruit. The patch varies in size and color. In early stages it is light green. It becomes brown and black as the fruit matures. Fruit tissues loose consistence, become sunken and the tip eventually takes a flattened appearance. Internal black rot can also develop in fruits with little or no external symptoms.

Trigger

Blossom End Rot is a physiological disorder that is caused by a lack of calcium in the fruit tissues. No pest or pathogens are involved. Calcium promotes strength and firmness of tissues. Calcium deficiency can occur due to the unavailability of this nutrient in the soil or the incapacity of the plant to absorb it and distribute it to its fruits. This leads to the destruction of the tissue structure, resulting in the characteristic dark, sunken areas. Irregular irrigation or root damage can be the cause of calcium deficiency.

Biological Control

Apply calcium-rich substances such as algal limestone, basalt flour, burnt lime, dolomite, gypsum and slag lime to the soil.

Chemical Control

Always consider an integrated approach with preventive measures together with biological treatments if available. Use a foliar spray of calcium chloride as emergency measure but do not spray too often or in excessive amounts.

Preventive Measures

Ensure regular irrigation during dry periods.,Avoid over-watering and allow for a good drainage of the fields.,Avoid root damage through deep cultivation practices.,Ensure fertilization low in nitrogen and rich in calcium.,Use nitrate forms of nitrogen rather than ammonium.,Adjust soil pH-levels, for example through liming.,Use mulch to keep soils moist.