Fruit Rot in Chilli Management

Identifying Fruit Rot: Symptoms and Causes

Fruit rot can manifest in different ways depending on the specific pathogen.

• Anthracnose (Colletotrichum capsici): This is the most common form. It appears as sunken, circular spots on green or ripe fruits. These spots are often dark brown or black, and in humid conditions, pinkish or orange spore masses can be seen in the center of the lesions. The disease can also affect stems and leaves, causing dieback.

• Phytophthora Fruit Rot (Phytophthora capsici): This rot causes water-soaked, dark green lesions on fruits, which quickly expand and turn brown. The entire fruit can become soft and watery. This pathogen also causes damping-off in seedlings, stem blight, and root rot.

• Bacterial Soft Rot: Less common but can occur, especially after injury. Fruits become soft, mushy, and emit a foul smell.

These pathogens thrive in specific environmental conditions.

Conditions Favouring Fruit Rot Development

Understanding the conditions that promote fruit rot helps in prevention.

• High Humidity and Rainfall: Prolonged periods of wetness on leaves and fruits, often due to heavy rains or frequent irrigation, create an ideal environment for fungal spore germination and infection.

• Warm Temperatures: Most fruit rot pathogens are active in warm, humid conditions, typically between 25-30°C.

• Poor Drainage: Waterlogging in the field stresses plants and provides a conducive environment for soil-borne pathogens like Phytophthora.

• Dense Plant Spacing: Overcrowding reduces air circulation within the canopy, leading to higher humidity around the fruits and leaves.

• Plant Injuries: Wounds caused by insects, mechanical damage, or hailstorms can provide entry points for pathogens.

Preventive Measures and Cultural Practices

Prevention is always better than cure. Implement these practices to reduce disease incidence:

• Use Healthy Seeds/Seedlings: Start with disease-free seeds or seedlings from a reputable source. Seed treatment can also be beneficial.

• Resistant Varieties: Whenever possible, choose chilli varieties known to have resistance or tolerance to fruit rot diseases prevalent in your area.

• Crop Rotation: Avoid planting chilli or other solanaceous crops (tomato, brinjal, potato) in the same field year after year. Rotate with non-host crops like maize, rice, or legumes for at least 2-3 years.

• Proper Spacing: Maintain adequate plant spacing (e.g., 60 cm between rows and 45 cm between plants) to ensure good air circulation and reduce humidity within the canopy.

• Field Sanitation: Remove and destroy infected plant debris and fallen fruits immediately to reduce the source of inoculum.

• Water Management: Use drip irrigation instead of overhead irrigation to keep foliage dry. If overhead irrigation is used, water in the morning so leaves can dry quickly. Avoid overwatering.

• Weed Control: Keep the field free of weeds, as they can harbor pathogens and increase humidity.

• Nutrient Management: Provide balanced nutrition to plants. Over-application of nitrogen can lead to lush, soft growth that is more susceptible to disease.

Chemical and Biological Control

When preventive measures are not enough, chemical or biological interventions may be necessary.

• Fungicides for Anthracnose:

  • For prevention, seed treatment with Carbendazim (2 g/kg seed) or Thiram (2.5 g/kg seed) can be done.

  • Foliar sprays with systemic fungicides like Carbendazim (0.5 g/L water) or Azoxystrobin (1 ml/L water) can be effective.

  • Contact fungicides like Mancozeb (2 g/L water) or Chlorothalonil (2 g/L water) can be used as protective sprays, especially before anticipated rain.

  • Start spraying at the first sign of disease and repeat every 7-10 days, alternating fungicides to prevent resistance development.

• Fungicides for Phytophthora Fruit Rot:

  • Fungicides containing active ingredients like Metalaxyl + Mancozeb (e.g., Ridomil Gold, 2 g/L water) or Propamocarb hydrochloride (2 ml/L water) are effective.

  • Soil drenching with these fungicides can also help control soil-borne infection.

• Biological Control:

  • Application of bio-fungicides containing Trichoderma viride or Pseudomonas fluorescens (5 g/L water or 2.5 kg/hectare mixed with farmyard manure) can help suppress soil-borne pathogens and enhance plant resistance. These can be used as seed treatment, soil application, or foliar spray.

Always follow the manufacturer's instructions for dosage and safety precautions.

Managing fruit rot in chilli requires an integrated approach, combining good cultural practices, selection of resistant varieties, and timely application of appropriate fungicides or bio-agents. Regular field monitoring for early symptoms and understanding the conditions that favor the disease are key to protecting your chilli crop and ensuring a healthy yield.