Brinjal pathology

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TopicBrinjal diseases and control

English Name Brinjal

Scientific Name Solanum melongena

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List of the disease

• Damping off • Phomopsis blight• Alternaria leaf spot • Fruit rot • Bacterial wilt• Little leaf of brinjal• Stem rot• Root knot• Mosaic

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Damping off

Causal Organism: (Phytophthora spp., Rhizoctonia spp.)

• Two types of symptoms are observed-

Pre-emergence damping-off Post-emergence damping-off

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Symptom

Pre-emergence damping-off

In this phase of disease, the young seedlings are killed before they emerge through the soil surface.

The radicle and the plumule, when they come out of the seed, undergo complete rotting.

Post-emergence damping-off

Infection of the young, juvenile tissues of the collar at the ground level.

The infected tissues become soft and become water soaked.

The collar portion rots and ultimately the seedlings collapse and die.

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Control

Healthy seed should be selected for sowing.

The seed should be treated with Thiram @ 2g/kg of seed before sowing.

Continuous raising of nursery in the same plot should be avoided.

Application of bio-control agent Trichoderma viride in soil @ 1.2kg/ha is also found effective to control damping-off to considerable extent.

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Phomopsis blight

• Causal Organism: (Phomopsis vexans)

Symptom : The disease is present in one or other form from the seedling stage to fruit maturity.

After transplanting, the leaves coming in contact with soil may get infected and show circular, grey to brown spots with light colored centre.

The affected leaves turn yellow and dry.

Sometimes petioles and stems are attacked and show cankers.

The skin peels off and the inner tissues are exposed.

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Control

Use healthy seed materials for sowing. After extraction of seeds it should be dried for a week and

then stored. Avoid continuous cultivation of brinjal. In the fields the affected plants and debris should be

collected and burnt. Spray Mancozeb 75 % WP @ 3 g per litre of water in the

early vegetative stage.

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Alternaria leaf spot

• Causal Organism: (Altrenaria melongenae)

Symptom:

The disease causes characteristic leaf spots with concentric rings.

The spots are mostly irregular and coalesce to cover large areas of the leaf blade.

The symptoms on the affected fruits are in the form of large deep-seated spots.

The infected fruits turn yellow and drop off prematurely.

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Control

Removal and destruction of affected plant parts .

Spraying the affected plants with Bavistin (0.1%) is useful for disease control.

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Fruit rot

• Causal Organism: (Phytophthora nicotianae)

Symptom:

The symptoms first appear as small water soaked lesions on the fruit, which later enlarges in size considerably.

Skin of infected fruit turns brown and develops white cottony growth.

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Control

Removal and destruction of the affected fruits.

Spraying the crop with Difolatan (0.3%) thrice at an interval of 10 days effectively controls the disease.

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Bacterial wilt

Causal Organism: (Psedomonas solancearum)

Symptom: Lower leaves wilt, vascular system become brown.

Wilting of the foliage followed by collapse of the entire plant.

The wilting is characterized by gradual, sometimes sudden, yellowing, withering and drying of the entire plant or some of its branches.

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Control

Removal and destruction of the affected plant parts and using disease resistant varieties help to reduce the disease incidence.

Crop rotation with ladies finger, tomato, potato should be avoided.

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Little leaf of brinjal

• Causal Organism: (Cestius (Hishimonus) phycitis and Amrasca biguttula biguttula)

Symptom: The characteristic symptom is the smallness of the leaves.

The petioles are so short and the leaves appear to be sticking to be stem.

Such leaves are narrow, soft, smooth and yellow.

Newly formed leaves are much more shorter. The internodes of the stem are also shortened.

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Control

Rogue out the affected plants.

The severity of the disease can be reduced by destruction of affected plants and spraying of insecticides.

New crop should be planted only when diseased plants in the field and its neighbourhood have been removed.

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Disease Picture

Stem rot Root Knot

Thanks to all

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