Management of the Root related wilt Diseases in Brinjal
- Damping off (Pythium, Phytophthora spp., Rhizoctonia spp., Sclerotium spp. and Sclerotinia spp.) Symptoms:
Damping off is a serious disease of brinjal seedlings and mainly occurs in nursery bed and newly transplanted seedlings. Infected seedlings rot at ground level and then the plants fall over ground. Fungi infect the germinating seeds at the initial stages and later spread to basal stem and developing roots. The diseased seedlings become pale green and brownish lesions are found at the collar region, resulting in bottling and topple over of seedlings.
- Avoid over-watering
- Drench the beds with Ridomet 1 gm/L + Spot 10 gm/L of water at 4- 5 days after germination
- The seedlings in the nursery should be sprayed with fungicides Ridomil gold 2 gm/L of water at regular intervals
Many times the brinjal crop is also infected by the Bacteria (Pseudomonas solanacearum), Fusarium, Verticilium dahlia and Pythium spp. Wilt disease is noticed when the brinjal plant attains 50 – 55 days after transplanting will start damping off. The bacteria or fungus will enter in to the tissues of the plant and block all the food and water conducting tissues avoiding the food and water flow to the growing parts of the plants. Adjacent plants will start to die and brinjal plants will damp off in patches 20 to 30 plants in a single season. Gradually the number may increase more and more. This wilt disease can cause similar symptoms in all Solanaceous crops like tomato, Potato, Chilli and Capsicum crops. Continuous cropping of the above crops will make the soil filled with virulent fungal spores for the upcoming crops.
2.1 Bacterial Wilt
2.1.1 Symptoms of bacterial Wilt: The characteristic symptoms include wilting of the foliage branch by branch from older to younger branches followed by collapse of the entire plant. Dropping and slight yellowing of leaves and vascular discoloration is a characteristic symptom of bacterial wilt disease. Drying of plants at the time of flowering and fruiting are also characteristic to the disease condition. Infected cut stems pieces when dipped in water, a white milky stream of bacteria oozes out which is the diagnostic symptom for bacterial wilt.
2.1.2 Management of Bacterial Wilt:
- Follow crop rotation
- Rogue out the infected plants and destroy them
- Raise nursery in disease free beds
- Seed treatment with Plantomycin 0.5 gm/L for 90 min
- Drench the beds with Blitox 3 gm/L + Treat 10 gm/L of water at 4- 5 days after germination. The same mixture may be drenched for infected plants at early stages about 50 – 100 mL per plant for three times at 10 days intervals
- Fungal Wilts
2.2.1 Symptoms of Fungal Wilt caused by Fusarium, Verticilium dahlia and Pythium spp
Slight yellowing of foliage and wilting of upper leaves are first symptoms of fungal wilts. Slowly the disease progresses making leaves turn dull-green to brown and remain attached to the plant. Reddish -brown streaks are visible in the vascular tissues when the stem and roots are cut diagonally. The underground stems’ corticals decay and become dry and brown/black and roots may have soft and water soaked appearance. The other symptoms of fungal wilts are stunted growth, withering of immature fruits, yellowing of lower leaves, drooping of the apical portion, browning of vascular bundles and ultimate drying of the whole plant. Wilting of seedlings is also a common characteristic of the diseases.
2.2.2 Management of Fungal wilts:
- Plant on raised beds to promote soil water drainage away from roots. Thoroughly disinfect equipment before moving from infested to clean fields
- Follow long term crop rotation with non solanaceous crop
- Grow resistant varieties
- Ridomet 1 gm/L + Spot 10 gm/L of water may be drenched for infected plants at early stages about 50 – 100 mL per plant for three times at 10 days intervals
The seedlings in the nursery should be sprayed with fungicides Ridomil gold 2 gm/L of water at regular intervals
Bacterial wilt, Pythium and Fusarium wilts can survive for years in the soil and is spread by water, insects and field equipments. The fungal disease develops fast during hot weather and the destruction intensity is when soil temperatures are at 25-30 ˚C. Low soil moisture with dry atmospheric weather supports the wilt plant disease.
Crop rotation and soil treatment with mechanical, Physical and biological methods will help to maintain the soil to be void of the fungal pathogen.
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K Sanjeeva Reddy,
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