Diseases of Fruit Plantation Medicinal and Aromatic Crops

Damping off of seedlings

Dramping off of seedlings

Causal organism: Rhizoctonia solani; Pythium aphanidermatum Nirvan

• It is also one of the serious diseases caused by fungi.
Symptoms

 
• This is a disease of young seedlings. On collar region discoloration takes place initially.
• Lesions are seen on the stem at or just above soil level.
• The stem becomes watery and shrinks, followed by death of the plant
 
Sources of inoculum

• Primary source of inoculum : Dormant mycelia
• Secondary source of inoculum: Sclerotial bodies.
• Spread: The disease spreads by way of cultural operations in the soil, irrigation water and wind blooms




Epidemiology

• Young seedlings are more susceptible to the disease than the elder ones.
• The disease is more severe in warm wet weather and becomes worst when seedlings are crowded.
• Well-drained soil should be used for planting and the crop should not be over irrigated.
Management

• Before sowing, seeds should be treated with fungal culture of Trichoderma viride (5 g/kg of seed) or Captan (3 g/kg of seed) to protect the newly emerging seedlings.