Para Wilt (or Parawilt) is a physiological disorder in cotton that occurs when plants experience sudden wilting, usually after irrigation or heavy rainfall. It primarily affects well-established cotton plants, causing significant yield loss if not managed properly.
Causes of Para Wilt in Cotton
1. Waterlogging:
– The most common cause of para wilt is excessive water in the root zone, often due to over-irrigation or heavy rainfall. This waterlogging creates anaerobic (oxygen-deficient) conditions around the roots, impairing their ability to function properly.
2. Oxygen Deficiency:
– When the soil is saturated with water, the roots are deprived of oxygen. This leads to root suffocation, reduced nutrient uptake, and subsequent wilting of the plant.
3. High Temperatures After Irrigation:
– If irrigation is followed by high temperatures, the sudden change in conditions can exacerbate the stress on the plant, leading to para wilt.
4. Root Damage:
– Damage to the roots from pests, diseases, or mechanical injury can predispose the plant to para wilt. Weakened roots are less capable of handling water stress, leading to wilting.
5. Nutrient Imbalances:
– Imbalances in soil nutrients, particularly calcium, can contribute to the occurrence of para wilt. Calcium plays a vital role in root health and function.
Why Para Wilt Occurs
Para wilt occurs due to a combination of factors that lead to a sudden and severe stress on the cotton plant. The disorder typically arises when the plant’s root system is unable to cope with abrupt changes in soil moisture and temperature, leading to impaired water and nutrient uptake. The roots, already stressed by waterlogging and oxygen deficiency, fail to support the above-ground parts of the plant, resulting in rapid wilting.
Management of Para Wilt in Cotton
1. Improved Irrigation Practices:
– Avoid over-irrigation and ensure proper drainage to prevent waterlogging.
– Use drip or sprinkler irrigation systems to provide uniform and controlled water supply.
– Schedule irrigation based on soil moisture levels and weather forecasts to avoid sudden water stress.
2. Soil Management:
– Improve soil structure by incorporating organic matter, which enhances drainage and reduces the risk of waterlogging.
– Use raised beds or ridges to allow excess water to drain away from the root zone.
– Ensure proper leveling of fields to avoid low-lying areas where water may accumulate.
3. Use of Gypsum:
– Apply gypsum (calcium sulfate) to improve soil structure and reduce sodium levels in sodic soils, which can help in better root health and reduce the incidence of para wilt.
4. Timely Application of Growth Regulators:
– Use of plant growth regulators like PGRs (Plant Growth Regulators) can help in improving root strength and reducing the impact of para wilt.
5. Adequate Nutrient Management:
– Maintain balanced soil nutrition, particularly focusing on calcium, potassium, and other essential nutrients to strengthen root systems.
– Conduct soil tests regularly to identify and correct nutrient deficiencies.
6. Drainage Improvement:
– In areas prone to waterlogging, improve field drainage systems to prevent water accumulation.
– Construct proper drainage channels around fields to quickly remove excess water after heavy rains.
7. Prompt Field Monitoring:
– Regularly monitor fields, especially after irrigation or rainfall, to detect early signs of para wilt.
– If symptoms are observed, stop irrigation immediately and take corrective measures to improve soil aeration.
By managing soil moisture levels, improving soil health, and ensuring proper irrigation practices, the incidence of para wilt in cotton can be minimized, leading to healthier plants and better yields.