Ppt on Phytoplasma-Induced Little Leaf Disease In Brinjal: Symptoms And Management

This presentation covers major diseases of brinjal (eggplant), focusing on their causal agents, symptoms, disease cycles, and management strategies. Emphasis is placed on identification, epidemiology, and integrated disease management. Key topics include little leaf, bacterial wilt, Phomopsis fruit rot, and Cercospora leaf spot. Important academic keywords: Phytoplasma, Ralstonia solanacearum, Phomopsis, epidemiology, management.
Introduction to Brinjal Diseases
  • Brinjal (Solanum melongena) is affected by several major diseases.
  • Diseases reduce yield and fruit quality significantly.
  • Understanding pathogens and symptoms is crucial for effective management.
Little Leaf Disease of Brinjal
  • Pathogen: Phytoplasma, localized in phloem sieve tubes.
  • Symptoms: Small, yellow, soft leaves; shortened petioles and internodes; bushy appearance.
  • Flowers, if formed, remain green; fruiting is rare and fruits are hard, necrotic, and mummified.
  • Spread by leafhoppers (mainly Hishimonas phycitis); survives in weed hosts.
Little Leaf Disease: Management
  • Grow tolerant varieties: Pusa Purple Round, Pusa Purple Cluster, Arka Sheel.
  • Destroy affected plants and eradicate solanaceous weeds.
  • Spray methyl demeton (2 ml/L) or apply phorate granules to soil.
  • Seed dip in tetracycline (10–50 ppm) to reduce infection.
Bacterial Wilt of Brinjal
  • Pathogen: Ralstonia solanacearum, a Gram-negative, motile rod.
  • Symptoms: Sudden wilting, leaf epinasty, yellowing, stunting, vascular browning, bacterial ooze from cut stems.
  • Soil and seed borne; survives in plant debris, wild hosts, and weeds.
  • Spread via irrigation water, infested soil, and contaminated tools.
Bacterial Wilt: Favourable Conditions and Management
  • Favoured by high soil moisture and temperature.
  • Resistant varieties: Pant Samrat, Arka Nidhi, Arka Neelakantha, Surya, BB 1, 44, 49.
  • Crop rotation with non-solanaceous crops; green manuring with Brassica spp.
  • Soil solarization (125 μm polyethylene, 8–10 weeks); biological control with Pseudomonas fluorescens, Bacillus spp.
  • Seed and soil treatment with antagonistic P. fluorescens; seedling dip before transplanting.
Phomopsis Fruit Rot (Phomopsis Blight)
  • Pathogen: Phomopsis vexans (asexual stage), Diaporthe vexans (sexual stage).
  • Attacks all growth stages; most destructive on fruits.
  • Symptoms: Damping-off in nursery, collar rot, leaf spots with pycnidia, stem cankers, sunken fruit spots, soft rot, mummified fruits.
  • Pathogen is seed-borne and survives in plant debris as mycelium and pycnidia.
Phomopsis Fruit Rot: Epidemiology and Management
  • Disseminated by rain splash, irrigation water, tools, and insects.
  • Favoured by high humidity, temperatures around 26°C, and wet weather.
  • Management: Remove crop debris, crop rotation, use disease-free seed.
  • Hot water seed treatment (50°C, 30 min); seed treatment with thiophanate methyl (1 g/kg).
  • Spray thiophanate methyl or carbendazim (0.1%) at 20-day intervals.
Cercospora Leaf Spot of Brinjal
  • Pathogen: Cercospora melongenae and related species.
  • Symptoms: Large, brown to grayish-brown circular or irregular leaf spots; coalescence leads to premature leaf drop and fruit rot.
  • Fungus survives in soil debris and infected seeds.
  • Favoured by high humidity, warm days, cool nights, and persistent dew.
Cercospora Leaf Spot: Management
  • Destroy crop debris; practice crop rotation and use disease-free seeds.
  • Maintain wider plant spacing to reduce humidity.
  • Spray zineb (0.25%), carbendazim (0.1%), or thiophanate methyl (0.1%) at 10–14 day intervals after disease onset.
Summary: Integrated Disease Management in Brinjal
  • Use resistant/tolerant varieties and certified disease-free seeds.
  • Practice crop rotation, field sanitation, and weed management.
  • Apply chemical and biological controls judiciously.
  • Monitor environmental conditions and implement timely interventions.