Leaf spot (Cercospora melongenae):
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1. Symptoms: The disease symptoms are characterized by chlorotic lesion, angular to irregular in shape, later turning greyish-brown.
2. Severely infected leaves drop off prematurely, resulting in reduced fruit yield.
3. Epidemiology and Disease cycle:
a. Pathogen survive on plant debris and other solanaceous weed host.
b. Moderately temperature with high humidity 80-85%). Is favorable for the diseases development.
4. Management
a. Removal and destruction of affected plant parts and spraying the affected plants with Carbendizim (0.1%) or
Chlorothalonil (2 g/litre of water) is useful for disease control.:
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Fruit Rot :(Phytophthora nicotianae):
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1. High humidity favours the development of the disease. The symptoms first appear as small water soaked lesions on the fruit, which later enlarges in size considerably.
2. Skin of infected fruit turns brown and develops white cottony growth.
3. Management:
4. Removal and destruction of the affected fruits and spraying the crop with Difolatan (0.3%)
5. thrice at an interval of 10 days effectively controls the disease.
Bacterial Wilt (Burkholderia solancearum):
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1. Symptoms:
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1. Bacterial wilt disease causes severe problem in brinjal cultivation.
2. The characteristic symptoms of the disease are wilting of the foliage followed by collapse of the entire plant.
3. The wilting is characterized by gradual, sometimes sudden, yellowing, withering and drying of the entire plant or some of its branches.
2. Control measures:
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1. Treat the seeds with hot water at 520C for 20 minutes or with 0.01% streptomycin solution for 30 minutes.
2. Proper crop rotation with non-solanaceous crops for at least 2 to 3 years reduces the infestation. Effective rotations are maize- okra- cabbage/cauliflower; maize-beans-maize, or okra-rice-mustard.
3. Apply bleaching powder @ 15-20 kg/ha and 4.5q lime to the land and mix it properly to the soil atleast 3-4 week before planting.
4. Proper drainage should be maintained.
5. A combination of Dhaincha as green manure crop and chemical soil amendment with lime and bleaching powder and application of biaogents as soil application [Trichoderma viride (2 kg) + Fluorescent Pseudomonads (2 kg)/ha along with organic manure (1:50 w/w) was most promising in management of wilt of solanaceous Vegetables.
6. Grow the tolerant germplasm like Arka Nidhi and BB-54.
7. Seedling should nbe deeped in solution of Streptocycline @1g/40 l of Water for 30 minutes
8. Spraying of Streptocycline 1g +10g COC 50% W.P in 20 l of water.
3. Disease cycle and Epidemiology:
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1. Soil and seed borne.
2. Secondary spread through insect, tools and rain drop splash.
Management:
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1. Removal and destruction of the affected plant parts and using disease resistant varieties help to reduce the disease incidence.
2. Crop rotation with Okra, tomato, potato should be avoided.
3. Before sowing, the seeds should be dipped in a solution of Streptocycline (1 g/ 40 litres of water) for 30 minutes.
4. Resistant Varieties: Muktakeshi and Pusa Purple Cluster.
Little Leaf of Brinjal (Phytoplasma/Mycoplasma ):
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1. This is a serious MLO disease of brinjal. The disease is transmitted by leaf hopper (Cestius (Hishimonus) phycitis and Amrasca biguttula biguttula). The leaves of the infected plants in the early stages are light yellow in colour. The leaves show a reduction in size and are malformed. Disease affected plant are generally shorter in stature bearing a large number of branches, roots and leaves than healthy plants.
2. The petioles get shorter considerably, many buds appear in the axil of leaves and internodes get shortened thus giving the plants a bushy appearance. Flower parts are deformed leading the plants to be sterile. Infected plants do not bear any fruit. However, if any fruit is formed it becomes hard and tough and fails to mature.
4. Management:
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1. Adopting sanitary measures including the eradication of susceptible volunteer crop plants from a previous planting can reduce the damage.
2. Use of barriers of trap crops and early removal and destruction of infected plants is also recommended. The sowing time can be adjusted to avoid the main flights of the beet leafhopper.
3. Spraying Malathion (2ml/litre of water) starting with the appearance of the leaf hoppers controls their population.
Mosaic (Potato Virus Y):
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1. This is a viral disease caused by Potato Virus Y.
2. The virus transmitted by aphids (Aphis gossypi) and Myzus persicae).
5. The important symptoms of the disease are mosaic mottling of the leaves and stunting of plants. The leaves of infected plants are deformed, small and leathery. Plants show a stunted growth when infected in the early stages.
1. Management:
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1. The disease incidence can be minimized by reducing the population of aphids.
2. Removal and destruction of infected plants and eradication of susceptible weed hosts.
3. In the nursery, aphids can be controlled by application of Carbofuran (1 kg a.i./ha) in the nursery bed at the time of sowing seeds followed by 2-3 foliar sprays of Phosphamidon (0.05%) at an interval of 10 days.
4. Spraying Phosphamidon (0.05%) at 10 days interval starting from 15-20 days after transplanting effectively controls the aphids in the field.
Damping Off:
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1. Pythium spp.,
2. Phytophthora spp
3. Rhizoctonia spp.
2. Symptoms:
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A. Pre-emergence damping-off:
a. The pre-emergence damping off results in seed and seedling rot before these emerge out of the soil.
B. Post-emergence damping-off:
a. The post-emergence damping off phase is characterized by 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.
3. Control measures:
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1. Hot water treatment of seeds (at 51.70 for 30 min)
2. Treat the seeds with Thiram / Captan @ 3 g / kg of seeds.
3. Drenching the nursery beds 7 days before sowing with Thiram / Captan or with any copper fungicide @ 3g / litre of water.
4. Cover the beds with transparent polythene sheets before sowing and left to open sun for at least 10 days, known as soil solarization.
5. Spraying the young seelding with 0.25% copper oxychloride or 0.25% metalaxyl-mancozeb.
6. Provision of proper drainage to the beds.
7. Remove the affected seedlings from beds as soon as the symptoms are visible.
8. Avoid flooding the beds to check spread of the disease.
9. Healthy seed should be selected for sowing.
10. Continuous raising of nursery in the same plot should be avoided.
11. Application of bio-control agent Trichoderma viride in soil @ 1.2kg/ha is also found effective to control damping-off to considerable extent.
Phomopsis blight(Phomopsis vexans) :
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1. This is a serious fungal disease of brinjal. Infected leaves show small, circular spots which become gray to brown with irregular blackish margin. The affected leaves may turn yellow and die. These lesions may also develop on the petiole and stem. On the fruits, soft, water decayed portion are observed which later turn black. The whole or major portion of the may rot. The disease is a major problem in seed crop. First Reported From Gujarat in 1914.
2. Control measures
a. Use seeds obtained from disease-free plants.
b. Treat the seeds with Thiram or Captan @ 2.5 g / kg of seed.
c. Keep the fields neat and clean all the time.
d. Hot water treatment of seeds before sowing at 500C for 30 minutes.
e. Spray the crop with Diathane M-45 @ 0.25% or Bavistin @ 0.1% at 7-10 days interval.
f. Collect and burn the diseased plants and fruits.
g. Grow the tolerant varieties like Pusa Bhairab, Pant Samrat etc.
h. A suitable crop rotation with leguminous or cucurbits may also help to reduce the disease infestation.
