Tomato disease management India-Tomato is one of the true joys vegetable gardener, but tomato can suffer from all kinds of tomato diseases and pest. Problems growing tomatoes are often the result of weather condition.
Tomato disease management India
Damping of seedlings
Pre-emergence damping-off of seedling consists of the killing of seedlings from initial stages of seed germination to the time of emergency above the soil due to rooting of seeds or radicle and plumule coming out of the seed. In case of post-emergency damping off, the seedling may topple over any coming out of the emergence from the soil due to rapid shrinking and darkening of cortical tissues of the hypocotyl. The infected tissues appear soft and water soaked. With the progress of the disease, the stems become constricted at the base and the plants fall down. The fungi are soil inhabitant and survive there in the form of oospores and sclerotia.
I) Burn a 30cm think stack of trash on nursery bed. This will provide partial sterilization of soil.
II) Treat seeds with Agrosan GN @ 3g/kg of seed or captan/Thiram @2.5g/kg of seed.
III) Drench the nursery beds with 0.4% captan/Thiram suspension 5-7 days after germination.
IV) Repeat the drenching after 7-10 days, if necessary.
The chief symptoms of the tomato disease management India appear on the leaves as circular to angular, dark brown to black spots. The concentric ridges often from the leathery necrotic tissue. Usually, a narrow chlorotic zone around the necrotic spots fades into normal green. The infected leaves wither, droop and drop off. The stems and fruits are also affected. On the stem dark spots appear at any point and it leads to collar rot. In case of fruit infection, the lesions start at the stem end as dark black or brown sunken spots. The lesions become leathery in consistency. The fungus remains viable in the dry infected leaves for more than a year. The fungus is carried on plant debris and seed.
i) Obtain the seeds from healthy fruits only.
II) Seeds should be disinfected with Thiram or Captan @ 3g/kg of seed before sowing.
III) After transplanting, spray the crop with Dithane M-45 @ 1.5kg in 500 liters of water/ha.
3. Late blight
The disease can attack any ground part of the plant at any stage of the crop growth. Water soaked brown to purple-black lesions develop at any point on leaflet, rachis, petiole, stem or leaf. These lesions advance rapidly to cause a severe blight under warm and humid conditions. In times of low humidity, the lesion growth is checked. On the lower side of the leaves, white fructification of the fungus appears at the joining point of pale and purple areas. On tomato fruits, dark olivaceous, greasy-appearing spots are formed. These may enlarge to cover the entire fruit. In very moist weather, a white weft of fungus growth develops in the invaded areas. The fungus survives on other host plants and on the potato refuse. The fungus also lives in soil. Potato and both are infected at the same time.
I) Use resistant cultivars
II) Spray the crop as recommended under early blight during February-March just after rains.
III) When the disease risk is heavy, spray the crop in mid-February with Ridomil MZ @ 1.25kg/ha. followed by 3sprays in Indofil M-45 @ 1.5kg/ha in 500 liters of water at 7 days intervals.
4. Buckeye rot or fruit rot
The disease appears on the fruits in the form of sports. The sports are pale brown with concentric rings. These sports may be small or they may cover a major portion of the fruit surface. If the green fruits are attacked, they show brownish circular spots at the blossom end, shrink and get mummified. The symptom appears mostly at the point of contact between fruit and soil. The disease is more prevalent in wet weather. The disease is soil-borne and the fungus survives in the soil.
I) Spray Difolatan @ 3g/liter of water there to fruit times at 10 days interval. Dithane M-45 is equally effective.
II) Staking of plants and remove of lower leaves and fruits help in preventing the disease.
III) Treat seeds with Agrosan GN @ 2.5g/kg seed.
IV) Provision of good soil drainage and destruction of weeds will check the disease in incidence.
V) Fungicide application recommends for blight of tomato will take care of this disease also.
The disease may appear at any time during the plant growth. The earliest symptoms appear as small, circular, water-soaked spots on the under the surface of the lower leaves. The spots enlarge and develop dark brown margins with sunken, white or grey centers. The centers of these spots on the upper surface of the leaves show minute, black fungal fruits bodies. The fungus survives in the soil and perennates through weed hosts.
I) Treat seeds with Agrosan GN or Thiram @ 2.5g/kg before sowing.
II) Follow crop rotation in the endemic areas.
III) Drench seedbeds with Thiram or Captan @ 3g/liter of water.
IV) Spray the seedling in nursery bed with Dithane Z-78 @2.5g/liter of water at 7 days intervals.
6. Fusarium wilt
The earliest symptoms on the young plants are clearing of veinlets and drooping of the petioles. The affected plants wilt and die. The lower leaves show yellowing and die. The symptoms continue to appear on successively younger leaves. In case of advanced stages of the disease browning of vascular system can be seen in a cross-section of the lower stem. Young plants wilt suddenly than the older plants. Lateral roots show a black rot condition in case of root infection. Fungal growth can be seen on dead plants as a pinkish layer in wet and humid conditions. The fungus survives in soil as chlamydospores or on the plant debris saprophytically.
I) Treat seeds with Bavistin @ 2.5g/kg of seed.
II) Give summer ploughing to the tomato field.
III) Collect and destroy the diseased crop debris including root material by burning.
IV) Follow suitable rotation for at least four years.
The chief symptom of the disease consists of yellowing of the lowest leaves which progress upward slowly. The infected leaves drop prematurely. There is sometimes necrosis of tissues from the tip and along the veins. There is a yellow halo around the necrotic areas. The plants are stunted and the fruit size is reduced. Vascular bundles become discolored. The fungus is a soil inhabitant and surveys in the form of resting mycelium and sclerotia.
Rotation of seedbed and drenching of nursery beds with chemicals as for damping off will reduce the infestation of fungus.
The typical symptom is wilting, stunting and yellowing of the foliage and finally collapse of the entire plant. The lower leaves may drop before wilting starts. The vascular system becomes brown and the lower exude the bacterial ooze when crosscut. The most conspicuous symptom is sudden drooping of leaves without yellowing and rotting of the stem from any point during continued humid weather with high temperature. The roots are healthy and well developed. The bacterium is present in the soil and persists for a long time in some soil. Infection always occurs through wounds caused by transplanting, weeding or nematode invasion.
I) Grow cruciferous plants like cauliflower in the infested field.
II) Rotation with cereal crops will check the incidence of the disease.
9. Bacterial Canker
The disease is characterized by the temporary or permanent wilting of leaflets at the extremities of the plant. The petioles droop down. Under certain conditions, yellowish-white streaks appear on the stem near the base and may crack open forming the cankers. The streaks later turn grey-brown. The leaflets of one side may show wilting whereas on another side may be healthy. On green fruits, the pathogen causes water-soaked spots which soon become surrounded by a white halo. The bacterium perpetuates in or on the seed, disease plant debris in soil and on the weed hosts like Solanum nigrum.
I) The disease can be controlled by extraction of seed through fermentation of seed and pulp at room temperature for 72 hours.
II) Crop rotation for 4 years, plant sanitation, and soil sterilization can control the disease.
10. Leaf curl (tomato disease management India)
The characteristic symptom is the severe stunting of plants with downward rolling and crinkling of the leaves. The newly formed leaves show chlorosis. The older, leaves become leathery and brittle. The infected plants look pale and produce more lateral branches giving a bushy appearance. The disease plants are partially or completely sterile in case of severe infection. The disease is more severe during the rainy season. The virus is transmitted by whitefly, Bemisia tabaci. Even a single viruliferous whitefly is able to transmit the virus. The same virus affects papaya and tobacco also.
I) Rogue out the affected plants.
II) Spraying of oxydemeton methyl 25EC or dimethoate 30EC @ 1.0ml/liter keeps the vector population low thereby reducing the incidence of the disease.
The affected plants exhibit mottling of leaves with raised dark green areas and some distortion and stunting of leaves. The mottling of leaves is very severer under the condition of high temperature and intense light. Sometimes the leaf blade is reduced to fernlike in appearance. The edges of the leaf turn download and are stiffer than the healthy leaves. The fruits are fewer, undersized and often deformed. The virus is transmitted by rubbing between diseased and healthy leaves in the field and also by sap. The virus perennates on susceptible weeds and ornamental plants.
I) Use virus free seedling.
II) Rogue out the mosaic affected plants from the seedbeds.
III) Collect and sow seeds from the healthy plants only.
IV) Spray with insecticide, viz. dimethoate 30EC or oxydemeton methyl 25EC @ 1.0ml/liter of water at 10 days interval.
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