Sesame: Diseases and Symptoms

Phyllody

• All floral parts are transformed into green leafy structures followed by abundant vein clearing in different flower parts.
• In severe infection, the entire inflorescences is replaced by short twisted leaves closely arranged on a stem with short internodes, abundant abnormal branches bend down.
• Finally, plants look like witches broom.
• If capsules are formed on lower portion of plant they do not yield quality seeds

• The disease is transmitted through jassids and the phytoplasma survives in leaf hopper throughout its life.

Dry root rot

• The fungus attacks young seedling, their stems become water soaked soft and incapable of supporting the seedling which falls over and dies.
• On older seedlings elongated brownish black lesions appear which increase in length and width girdling the stem and plant dies.

Survival and spread - The pathogen survives in seed and soil.

Favourable conditions - High soil temperatures and moisture stress conditions favour the development of the pathogen.

Phytophthora blight

Disease can occur at all stages of the plant.

• Initial symptom is water soaked spots on leaves and stems.
• The spots are chestnut brown in the beginning later turn to black.
• Premature leaf fall occurs.
• In humid weather, severity of disease increases, main root is affected, diseased plants are easily pulled out and produce shriveled seeds and gives blighted appearance.

• The pathogen survives in soil

• High soil moisture favours the development of the pathogen.
• The disease is severe in the area of heavy soil with high rainfall

Alternaria blight

• The pathogen attacks all parts of the plant at all stages.
• Small, dark brown water soaked, round to irregular lesions, with concentric rings, 1-8 mm in diameter appear on the leaves and under excessive atmospheric and soil humidity the spot increases in size and number.
• The lesions may also appear on the midrib and veins of the leaves.
• Milder attacks cause only defoliation, in severe cases the plant may die.

• The pathogen is seed borne.
• Temperature of 20-30^o C and high humid conditions favour the disease.

IPM for Sesame

To know the IPM practices for Sesame, click here.

Source: NIPHM and Directorate of Plant Protection, Quarantine & Storage