Internal necrosis

Internal necrosis is a physiological disorder characterized by the localized death of plant tissues within fruits, tubers, or roots, often occurring without obvious external symptoms. Unlike infectious diseases caused by pathogens, this condition is primarily triggered by metabolic disruptions, nutritional imbalances, or environmental stress, which lead to cellular breakdown and decay from within.

The disorder frequently affects solanaceous crops, including tomatoes, peppers, and potatoes. In potatoes, it is commonly known as internal brown spot or rust spot, manifesting as small patches of necrotic tissue. In tomatoes, the symptoms appear as internal browning of the fruit flesh, which can significantly reduce the overall quality and marketability of the harvested produce.

Development is driven by environmental instability and nutrient deficiencies, specifically a lack of calcium, boron, or magnesium. Excessive heat, irregular irrigation, and pH imbalances in the soil can disrupt the plant's vascular system, preventing the adequate distribution of essential nutrients to developing tissues. When tissues are deprived of these building blocks, cells lose structural integrity and start to die.

The economic impact is substantial because the damage is often discovered too late, such as during grading or packaging. Affected fruits and tubers have a significantly reduced shelf life, as the dead tissue provides a perfect entry point for opportunistic saprophytic fungi and bacteria, leading to accelerated rotting during storage and transit.

Effective management requires a proactive approach to crop nutrition and environmental control:

• Monitoring soil moisture to prevent fluctuations that impede nutrient uptake.
• Applying foliar calcium and boron sprays during critical fruit or tuber development stages.
• Managing soil pH to ensure optimal nutrient availability.
• Selecting cultivars that are bred for better tolerance to physiological stress and nutritional efficiency.