Diseases of Fruit Plantation Medicinal and Aromatic Crops

Leaf Spot

Causal organism: Pseudomonas spp.
Symptoms

• Disease affect the aerial part of the plant.
• Spots on the leaflets are water soaked, round, oval or irregular.
• Several such spots may coalesce to produce a blighted appearance.
• No yellowing, healthy plant sudden wilts due to faster spread of the disease.
• No epinasty. Vascular browning, white or milky white colored oozing are common.
• Complete plant dries up.
Etiology

• Gram –ve bacteria, lopotrichus, rod shaped, unicellular bacteria, reproduction by binary fusion.
• Mode of spread and survival:
• They are present on the plant debries and the seeds.
• Infection usually occurs through leaf stomata .
• Primary Source of Inoculum: Affected self sown crop, soil.
• Secondary source on inoculum: Soil born bacterial cells through irrigation water.
Epidemiology

• High humidity that is 85 -92 % and free water facilitate disease development.
• The optimum Temperature for disease development is 24 to 27 ⁰ c.
• High soil moisture is needed with Neutral pH.
• Affected sandy loam and sandy clay soils.
Management

• Clean seed offer better control.
• Seed treatment with Streptomycin 0.05 % is affective.
• Provide good soil drainage, wide row spacing, Host destruction, eradication of weeds.
• Use clay loam soil Crop rotation with non host crop
• Avoid movement of water from infected to healthy area.