Diseases of fruit plantation medicinal and aromatic crops (2+1)

Cercospora leaf spot

Causal organism: Cercospora punicae P.Henn.
Symptoms

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

• Conidiophores are olivaceous brown, short fasciculate, sparingly septate. Conidia are hyaline to pale olivaceous, cylindrical, sub fusoid to sub - clavate, septate.
Life cycle

Mode of survival and Spread

• The pathogen survives in infected plant parts as dormant mycelia and spreads through airborne conidia produced in acervullus.
Epidemiology

• The disease becomes severe during August to November, when there is high humidity and atmospheric temperature between 20 to 27°C
Management

• Cultural practice
• Clean cultivation, i.e. sanitation, including removal of weeds.
• Spray nitrogen solution or bleaching powder to enhance degradation of fallen leaves or infected plant parts.
• Cut all the affected branches and burn.
• pruned area should be smeared with Bordeaux paste or COC paste.
• Chemical
• Spray thiophanate methyl (0.1%) or mancozeb (0.2%) or cardendazim (0.1%) on the plants.