Major Brinjal diseases are:-
1.Bacterial Wilt: Pseudomonas solanacearum
Symptom:
- Bacterial Wilt symptoms on leaf surface Wilting, stunting, yellowing of the foliage and finally collapse of the entire plant are the characteristic symptoms of the disease.
- Lower leaves may droop first before wilting occurs.
- The vascular system becomes brown.
- Bacterial ooze comes out from the affected parts.
- Plant show wilting symptoms at noontime will recover at nights but die soon.
Management:
- Pant samrat variety is tolerant.
- Crop rotation with cruciferous vegetables such as cauliflower help in reducing the disease incidence.
- Fields should be kept clean and effected parts are to be collected and burnt.
- Spray Copper fungicides to control the disease (2% Bordeaux mixture.)
- The disease is more prevalent in the presence of root knot Nematodes, so control of these nematodes will suppress the disease spread.
2.Cercospora Leaf Spot :Cercospora solani -melongenae, C. solani
Symptom:
- The leaf spots are characterised by chlorotic lesions, angular to irregular in shape, later turn grayish-brown with profuse sporulation at the centre of the spot.
- Severely infected leaves drop off prematurely, resulting in reduced fruit yield.
Management:
- Pant Samrat variety is resistant to both the leaf spots.
- Diseases can be managed by growing resistant varieties.
- Spraying 1 per cent Bordeaux mixture or 2 g Copper oxychloride or 2.5 g Zineb per litre of water effectively controls leaf spots.
3.Alternaria leaf Spot: Alternaria melongenae, A. solani
Symptom:
- Cracks appearing in leaf spot
- The two species of Alternaria occur commonly, causing the characteristic leaf spots with concentric rings.
- The spots are mostly irregular, 4-8 mm in diameter and may coalesce to cover large areas of the leaf blade.
- Severely affected leaves may drop off.
- A. melongenae also infects the fruits causing large deep-seated spots.
- The infected fruits turn yellow and drop off prematurely.
Management:
- Spraying 1 per cent Bordeaux mixture or 2 g Copper oxychloride or 2.5 g Zineb per litre of water effectively controls leaf spots.
4.Damping off: Pythium aphanidermatum, Pythium indicum, , Phytophthora parasitica, Rhizoctonia solani andSclerotium rolfsii.
Symptom:
- Sudden collapsing of the seed lines occur in the seed bed.
- The seedlings are attacked at the collar region and the attacked seedlings are toppled down.
- The disease spreads through fungi present in the soil. The disease spreads through fungi present in the soil.
Management:
- The disease can be controlled by seed treatment with agrosan or ceresin @2gm/kg of seed
5.Tobacco mosaic virus (TMV)
Symptom:
- Mosaic mottling of leaves and stunting of plants are the characteristic symptoms of potato virus Y Mosaic symptoms are mild in early stages but later become severe.
- Infected leaves are deformed, small and leathery. Very few fruits are produced on infected plants.
- The important symptom produced by tobacco mosaic virus is conspicuous mottling of leaves.
- Leaves also develop blisters in advanced cases. Severely infected leaves become small and misshapen. Plants infected early remain stunted.
- PVY is easily sap transmitted.
- It is transmitted in the field through aphids, Aphis gossypii and Myzus persicae and perpetuates on weed hosts like Solanum nigrum and S.xanthocarpum.
- TMV is transmitted by sap, contaminated implements and clothes, soil debris and hands of labour.
- It can perpetuate on many cultivated plants like cucurbits, legumes, pepper, tobacco, tomato and weed hosts. The virus survives in plant debris in the soil.
Management:
- Destroy all weeds and avoid planting cucumber, pepper, tobacco, tomato near brinjal seed beds and field.
- Wash hands with soap and water before working in seed beds.
- Prohibit smoking or chewing of tobacco who are handling brinjal seedlings.
- Spray insecticides like Dimethoate 2 ml/litre or Metasystox 1 ml/litre of water to control the insect vectors.
6.Collar rot: Sclerotium rolfsii
Symptom:
- The disease occasionally occurs in serious form.
- The lower portion of the stem is affected by the soil borne inoculum (sclerotia).
- Decortications is the main symptom.
- Exposure and necrosis of underlying tissues may lead to the collapse of the plant.
- Near the ground surface on the stem may be seen the mycelia and sclerotia.
- Lack of plant vigour, accumulation of water around the stem, and mechanical injuries help in the development of this disease.
Management:
- Seed treatment with 4 g of Trichoderma viride formulation per kg seed will help in reducing the disease.
- Spraying with Mancozeb @ 2g/Litre of water.
- Collection and destruction of diseased parts and portions of the plant.
Source-
- TamilNadu Agritech Portal
