Blossom-end rot

Blossom-end rot is a common physiological disorder in many vegetables and fruits. It is not caused by fungi, bacteria, or viruses, but by a localized calcium deficiency within the fruit, which often occurs during periods of rapid growth when the plant cannot supply calcium fast enough to the developing fruit.

This condition frequently affects a wide range of crops including tomatoes, bell peppers, eggplant, and watermelon. It typically appears on the fruits when they are still in the early stages of development and maturation.

The primary symptom is a small, water-soaked spot at the blossom end (the bottom) of the fruit. As the condition progresses, the lesion darkens, becomes sunken, leathery, and often turns dark brown or black. The tissue becomes dehydrated, and while it may start as a dry rot, it can later be colonized by secondary pathogens.

The development of blossom-end rot is heavily influenced by environmental conditions. Irregular watering, prolonged drought, or excessive salinity in the soil can restrict root uptake of calcium. Furthermore, high humidity, high temperatures, and excessive nitrogen application can aggravate the issue by promoting rapid vegetative growth at the expense of fruit quality.

To effectively prevent blossom-end rot, it is essential to maintain consistent soil moisture levels throughout the growing season. Applying calcium fertilizers, particularly as foliar sprays during fruit set, can help mitigate the deficiency. Proper soil management and avoiding excessive fertilization with nitrogen are also crucial strategies for control.

• Maintain consistent and even soil moisture.
• Apply foliar calcium treatments during fruit development.
• Use mulch to conserve soil moisture.
• Avoid excessive nitrogen fertilizer application.