Diseases of Fruit Plantation Medicinal and Aromatic Crops

Leaf Blight

Causal organism: Cercospora foeinicoli
Symptoms

• Light brown zonate spots appear on the leaves.
• Black and elliptic spots appear on the twigs.
• The affected areas in the twigs become flattened and depressed with raised edges. Such infected twigs dry up.
• In severe cases the whole plant dies.
Etiology

• Conidiophores are olivaceous brown, short fasciculate, sparingly septate and 20 to 40 x 3 µm. Conidia are hyaline to pale olivaceous cylindrical, sub fisoid to sub clavate, septate and 40 to 50 x 3 µm
• Mode of survival and Spread: The pathogen survives in affected plant parts as dormant mycelia and spreads through air borne conidia.
Epidemiology

• The disease is severe during August to November. When there is high humidity and the temperature between 20 and 27^o C
Management

• Clean cultivation, i.e. sanitation, includes removal of weeds.
  
• On fallen leaves or affected plant parts, spray nitrogen solution or bleaching powder to enhance degradation.
  
• Smear with Bordeaux paste or coc paste.
  
• Spray thiophonate methyl 0.1 % or mancozeb 0.25 % or cardendazim 0.1%.