Cotton anthocyanosis

Cotton anthocyanosis is a non-infectious physiological disorder characterized by the accumulation of anthocyanin pigments in the leaves and stems of the cotton plant. This color change occurs when the plant's metabolic pathways are disrupted, often as a stress response to environmental or nutritional limitations.

This condition affects the Gossypium species, specifically in commercial cotton-growing regions. Plants at the seedling and vegetative stages are particularly susceptible, as their rapid growth rate requires a consistent and balanced supply of nutrients and favorable environmental conditions to maintain metabolic stability.

The primary clinical signs include the development of a reddish or purplish cast on the foliage. This discoloration typically begins on the older leaves and progresses upwards. Affected leaves may become brittle, show marginal necrosis, and eventually drop prematurely, which severely inhibits the plant's ability to photosynthesize effectively.

The development of anthocyanosis is triggered by several abiotic stressors, including low temperatures, nutrient imbalances (most notably magnesium, phosphorus, or nitrogen deficiency), and water-logging, which restricts root oxygenation. These conditions inhibit the plant's ability to synthesize chlorophyll, leading to the increased expression of anthocyanins.

Management strategies focus on addressing the underlying nutritional and environmental constraints to support plant health:

• Regular soil testing to identify and correct nutrient deficiencies.
• Foliar applications of micronutrients to alleviate immediate stress.
• Improving soil drainage and structure to facilitate root development.
• Implementing appropriate irrigation scheduling to prevent water stress.

The economic impact of cotton anthocyanosis can be substantial, as it leads to reduced plant vigor, stunted growth, and a significant decline in both yield and fiber quality. Effective crop management remains the only viable strategy for preventing this physiological condition and ensuring the commercial success of the cotton harvest.