Control Diseases of: Sorghum, Bajra, Pigeonpea, Greengram ,Blackgram and Sesame!
Contents:
- How to Control Diseases of Sorghum?
- How to Control Diseases of Bajra?
- How to Control Diseases of Pigeonpea?
- How to Control Diseases of Greengram?
- How to Control Diseases of Blackgram?
- How to Control Diseases of Sesame?
1. How to Control Diseases of Sorghum?
Diseases Control:
Sorghum is infested by a large number of stem, leaf and panicle diseases. A brief description of symptoms and management of important diseases of sorghum is presented hereunder.
1. Head Smut (Sphacelotheca reiliana):
The entire ear head is either completely or partially replaced by a large whitish gall. The spores are blown away, exposing the dark filaments.
Management:
In the areas where the disease occurs commonly, the best practice is to plant resistant cultivars. Seed treatment with Carboxin (Vitavax) @ 2g/kg of seed. Collect smutted ear heads in cloth bags in dip in boiling water.
2. Covered Kernel Smut (Sphacelotheca sorghi):
The individual grains are replaced by smut sori. Sori are covered with creamy skin. Sori can be localized at a particular part of the head, or can occur over the entire inflorescence. Ratoon crops exhibit a higher disease incidence.
Management:
Seed treatment with Carboxin (Vitavax) @ 2g/kg or Captan/Thiram 4g/kg of seed. Collect smutted earheads in cloth bags and destruct by dipping in boiling water. Avoid ratooning.
3. Long Smut (Tolyposporium ehrenbergii):
Relatively small proportion of the florets are infected. The sori or spore sacs are cylindrical, elongate, usually slightly curved with a relatively thick creamy-brown covering membrane.
Management:
Seed treatment with Carboxin (Vitavax) @ 2g/kg or Captan/Thiram 4g/kg of seed. Collect smutted earheads in cloth bags and destruct by dipping in boiling water. Avoid ratooning.
4. Loose Smut (Sphacelotheca cruenta):
The sori, which vary in length from 3 to 18 mm, is the solid long black (often curved) pointed columella which extends almost the full length of the sorus and which remains conspicuous after the smut spores have been blown away.
Management:
Seed treatment with Carboxin (Vitavax) @ 2g/kg or Captan/Thiram 4g/kg of seed. Collect smutted earheads in cloth bags and destruct by dipping in boiling water. Avoid ratooning.
5. Downy Mildew (Sclerospora sorghi):
Abundant downy white growth is produced nocturnally on the under surfaces of infected portions of leaves during humid weather.
Management:
Infested plants should be removed as and when the symptoms are noticed.
Treat seeds with Metalaxyl at 6 g/kg followed by one spraying with Metalaxyl 500 g or Metalaxyl + Mancozeb 1 kg/ha or Mancozeb 1 kg/ha. Crop rotation with pulses or oilseed crops.
6. Rust (Puccinia purpurea):
The pustules are elliptical and parallel with the leaf veins. In highly susceptible cultivars the pustules occur so densely that almost the entire leaf tissue is destroyed.
Management:
Spray Wettable sulphur 2.5 kg or Mancozeb 1 kg/ha. Repeat the application of any one of the fungicides 10 days after. Control measures are to be adopted when there is rust incidence in the early stages as spread of infection to top leaves results in poor grain filling.
7. Anthracnose and Red Rot (Colletotrichum graminicola):
Many lesions may develop close together and coalesce to kill large portions of the leaf. Mid-rib infection often occurs and is seen as elongate-elliptical red or purple lesions on which the black acervuli can be clearly seen. Infected stems when split open show discoloration (depending on cultivar) which may be continuous over a large area, or more marbled appearance.
Management:
Seed treatment with Captan or Thiram @ 4g/kg of seed. Spray with Mancozeb 1 kg/ha.
8. Cereal Grain Molds- A Complex of Several Fungal Species:
The most commonly isolated Fusarium species are F. semitectum and F. moniliforme, and grains infected with these fungi develop a fluffy white or pinkish coloration. Curvularia lunata is also frequently encountered and this fungus colors the grains black.
Management:
Spray Mancozeb 1 kg/ha or Captan 1 kg + Aureofungisol 100g/ha if intermittent rainfall occurs during earhead emergence, a week later and during milky stage.
2. How to Control Diseases of Bajra?
Disease Control:
Among various factors responsible for low productivity of pearl millet, diseases infestation is major yield limiting factor.
Important diseases and their management are given below:
1. Downy Mildew (Sclerospora graminicola):
Symptoms:
Symptoms often vary as a result of systemic infection. Leaf symptoms begin as chlorosis at the base and successively higher leaves show progressively greater chlorosis. Infected chlorotic leaf areas can support abundant white asexual sporulation on the lower leaf surface. Severely infected plants are generally stunted and do not produce panicles. Green ear symptoms result from transformation of floral parts into leafy structures.
Management:
Grow downy mildew resistant hybrids like HHB-50, HHB-67, PHB- 47, PCB-15, HC-4, WCC-75, etc. Transplanting reduces disease incidence. At the time of planting infected seedlings should be removed.
In the direct sown crop, infested plants should be removed upto 45 days after sowing as and when the symptoms are noticed. Treat the seeds with Metalaxyl at 6 g/kg followed by one spraying with Metalaxyl 500 g or Metalaxyl + Mancozeb 1 kg/ha or Mancozeb 1 kg/ha.
2. Ergot (Claviceps fusiformis):
Symptoms:
Cream to pink mucilaginous droplets of “honeydew” ooze out of infected florets on pearl millet panicles. Within 10 to 15 days, the droplets dry and harden, and dark brown to black sclerotia develop in place of seeds on the panicle. Sclerotia are larger than seed and irregularly shaped, and generally get mixed with the grain during threshing. Conditions favoring the disease are relative humidity greater than 80%, and 20 to 30°C temperatures during flowering.
Management:
Use certify seeds for sowing, if there is possibility of ergots being mixed with seed, dip the seeds in 20 % salt solution. The ergots would float on the surface which may be removed and burnt. The sound seeds that settle at the bottom should be washed thoroughly with fresh water and dried in shade.
After drying, the seed should be treated with a mixture of 2 g Emisan and 4 g Thiram/kg of seed. Spray the crop with Carbendazim 500 g or Ziram 1000 ml or Mancozeb 1 kg/ha at boot leaf stage. The 2nd and 3rd sprays should be given at 10 days intervals.
3. Rust (Puccinia substriata):
Symptoms:
Small reddish-brown to reddish orange, round to elliptical uredinia develop mainly on foliage. As severity of infection increases, leaf tissue will wilt and become necrotic from the leaf apex to base. In infection sites developing late in the season, uredinia are replaced by telia which are black, elliptical, and subepidermal.
Management:
Spray wettable sulphur 2.5 kg or Mancozeb 1 kg/ha when the initial symptoms of the diseases are noticed. Repeat the application at 10 days intervals. Sowing during December – May result in less incidence of rust disease. Control measures are to be adopted when there is rust incidence in the early stages as spread of infection to top leaves results in poor grain filling.
4. Smut (Tolyposporium peninillaria):
Symptoms:
It is one of the important diseases affecting ears. The diseased kernels are green in the beginning and generally larger in size than healthy ones. These are full of fungal spores. The green colour is due to the green membrane surrounding the black mass of fungal spores. The colour of the membrane later turns to black.
Management:
Give deep ploughing during summer. Follow a three year crop rotation, and Spray the crop with 0.15% Vitavax (1.5 kg Vitavax mixed in 1000 litres of water per hectare) at boot leaf followed by one or two sprays at ten days intervals.
5. Leaf Blast (Pyricularia setariae):
Symptoms:
The symptoms of this disease can be seen on the lower surface in the form of light to dark brown, boat shaped lesion. Sometimes several spots coalesce and form larger patches. In severe infection leaves are completely dried.
Management:
The disease can be controlled effectively by two or three sprays of 0.2% Zineb.
3. How to Control Diseases of Pigeonpea?
1. Wilt:
This disease is caused by fungus, Fusarium oxysporum f.sp. udum which survives in off season on the plant trashes in the soil. The leaves of the affected plants become yellowish in colour, then drop and finally the whole plant dry out.
Control:
It is difficult to control the disease due to the soil-borne nature of the causal fungus. However, its incidence can be reduced considerably by taking certain precautions. These include following a 3-4 year crop rotation, taking a mixed crop of jowar and arhar and collecting and burning the plant trashes left after harvesting. Best control is to plant disease resistant varieties like Amar, Azad, Asha (IPCL-87119), Maruthi, C-l 1, BDN-1, BDN-2, NP- 5 etc.
2. Stem Rot:
This disease is caused by a fungus Phytopthora drechsleri var. cajani. The disease affected plants show formation of brown to dark brown lesions on the stems near the soil surface. These lesions rapidly girdle the whole stem because of which the plant starts drying. The symptoms can be confused with symptoms of the wilt disease.
But this disease can be differentiated from wilt by examining the roots which remain healthy in this case. Also, plants affected by stem rot cannot be easily pulled out. They break at the affected stem position whereas wilt affected plants are easy to pull out.
Control Measures:
This disease can be controlled by planting resistant varieties. There should be good drainage in the field and the plants should be protected from stem injury.
3. Sterility Mosaic:
It is caused by sterility mosaic virus. It is an important disease of arhar. The virus is spread from plant to plant under field conditions through Eriophyid mite. The affected plants become light greenish in colour which can be easily differentiated from dark green healthy plants. Leaves are reduced in size. Affected plants remain stunted and branch profusely, as a result of which they appear bushy. No flowers and fruits are borne on such affected plants resulting in total loss of yield.
Control Measures:
Plant resistant varieties like Pusa-885, Asha, Sharad (DA-11), Narendra-Arhar-1, Bahar etc. Control mites by spraying 0.1% Oxydemeton methyl (Metasystox). Start spraying as soon as first affected plants are seen in the field. Three to four sprays are needed to control the mites.
4. How to Control Diseases of Greengram?
Mungbeans are susceptible to the usual array of pathogens which attack other legumes as described hereunder:
1. Anthracnose (Colletotrichum lindemuthianum):
Symptom:
The fungus attacks all aerial part parts and at any stage of plant growth. Symptoms are circular, black, sunken spots with dark center and bright red orange margins on leaves and pods. In severe infections, the affected parts wither off. Seedlings get blighted due to infection soon after seed germination.
Management:
Seed treatment with Carbendazim 2g/kg of seed. Spray Mancozeb 2g or Carbendazim 0.5g/lit.
2. Bacterial Leaf Blight (Xanthomonas phaseoli):
Symptom:
It is characterized by many brown, dry and raised spots on the leaf surface. When the disease is severe several such spots coalesce, the leaves become yellow and fall off prematurely. The lower surface of the leaf appears red in colour due to the formation of raised spots. The bacterium is also seed-borne. The stem and pods also get infected.
Management:
Use disease free seed. Destruction of debris and stubbles. Soak the seeds in 500 ppm Streptocycline solution for 30 min. before sowing followed by two sprays of Streptocycline combined with 3 g of Copper Oxychloride per litre at an interval of 12 days is recommended.
3. Cercospora Leaf Spot (Cercospora canescens):
Symptom:
This is an important disease of green gram and is usually occurs in a severe form, causing heavy losses in yield. Spots produced are small, numerous in number with pale brown centre and reddish brown margin. Similar spots also occur on branches and pods. Under favourable environmental conditions, severe leaf spotting and defoliation occurs at the time of flowering and pod formation.
Management:
Intercrop with tall growing cereals and millets. Follow clean cultivation. Use disease free seed. Maintain low crop population density and wide row planting.
Mulching reduces the disease incidence resulting in increased yield. Cercospora leaf spot can be controlled with Carbendazim 0.5g/lit. or Mancozeb 2.0g/lit.
4. Leaf Crinkle Disease (Leaf Curl Virus):
Symptoms:
The earliest symptoms appear on youngest leaves as chlorosis around some lateral veins and its branches near the margin. The leaves show curling of margin down wards. Some of the leaves show twisting. The veins show reddish brown discolouration on the under surface which also extends to the petiole.
Plants showing symptoms within 5 weeks after sowing invariably remain stunted and majority of these die due to top necrosis within a week or two. Plants infected in late stages of growth do not show severe curling and twisting of the leaves but show conspicuous venial chlorosis anywhere on the leaf lamina. The disease develops in the fields mainly through seed or rubbing of diseased leaves with the healthy ones.
Management:
Periodical removal of infected plants upto 45 days. Spray Acephate 1g/lit or Dimethoate 2 ml/lit to control vector.
5. Macrophomina Blight (Macrophomina phaseolina):
Symptoms:
In rice fallows, symptoms appear on 4 weeks old crop as raised white cankers at the base of the stem. These enlarge gradually and turn as raised brown streaks spreading upwards. Plants are stunted and leaves are dark green, mottled and reduced in size. Normal leaves on the affected plants drop suddenly and dry. Flowering and podding are greatly reduced.
When the affected plants are split/open vertically from the collar downwards, reddish discolouration of the internal tissues is clearly visible while the internal root tissues appear white. The pathogen can survive through seed, soil, diseased plant parts and host plants. The severity of the disease increases with the increase in temperatures. Fungus survives in upper layers of the soil and enters plant through stem.
Management:
Deep ploughing in summer. Follow crop rotation. Soil amendment with farm yard manure @ 12.5 tonnes/ha is helpful in reducing the incidence of the disease.
Destroy the diseased plant debris by burning of burying in the soil. Seed treatment with T. viride @4g/kg or P. fluorescens @ 10g/kg of seed or Carbendazim or Thiram 2g/kg of seed. Spot drenching with Carbendazim 1g/lit or P. fluorescens/T. viride 2.5 kg/ha with 50 kg FYM.
6. Yellow Mosaic (Mungbean Yellow Mosaic Virus):
Symptoms:
This disease is widespread in Uttar Pradesh as well as in other states of northern India. The symptoms of the disease appear within a month after sowing. These are first visible in the form of yellow, diffused, round spots scatters on the leaf lamina.
These spots expand rapidly and the leaves show yellow patches alternating with green colour of the leaves. The newly emerging leaves after initial symptoms show these symptoms right from the beginning. The affected leaves later turn completely yellow and get reduced in size.
Management:
The best method to control disease is to grow resistant varieties like Asha, Pant mung-4, Narendra Mung-1, PDM-11, PDM-54, ML-337 etc. Spray the crop twice or thrice with insecticides. These include Oxydemeton methyl (Metasystox 0.1%) + Melathion (0.1%) at 10 days interval. The first spray should be given as soon as the symptoms appear in the crop.
7. Powdery Mildew (Erysiphe polygoni):
Symptoms:
Powdery mildew is one of the widespread diseases of several legumes in green gram. White powdery patches appear on leaves and other green parts which later become dull coloured. These patches gradually increase in size and become circular covering the lower surface also. When the infection is severe, both the surfaces of the leaves are completely covered by whitish powdery growth.
Severely affected parts get shriveled and distorted. In severe infections, foliage becomes yellow causing premature defoliation. The disease also creates forced maturity of the infected plants which results in heavy yield losses.
Management:
The seeds must be sown early in the month of June to avoid early incidence of the disease on the crop. Powdery mildew could be controlled by spraying Carbendazim 1g/lit or Tridemorph 1 ml/lit.
8. Root Rot and Leaf Blight (Rhizoctonia solani):
Symptoms:
The pathogens cause seed decay, root rot, damping-off, seedling blight, stem canker and leaf blight. The disease occurs commonly at podding stage. In the initial stages, the fungus causes seed rot, seedling blight and root rot symptoms. The affected leaves turn yellow in colour and brown irregular lesions appear on leaves. On coalescence of such lesions, big blotches are formed and the affected leaves start drying prematurely.
Roots and basal portion of the stem become black in colour and the bark peels off easily.
The affected plants dry up gradually. When the tap root of the affected plant is split open, reddening of internal tissues is visible. The pathogen is soil-borne.
Management:
Avoid moisture stress in the soil especially at podding stage. Treat the seeds with T. viride @ 4g/kg or P. fluorescens @ 10g/kg of seed or with fungicides like carbendazim or thiram 2g/kg of seed. Spot drenching with carbendazim 1g/lit or P. fluoresceins/T. viride 2.5 kg/ha mixed with 50 kg FYM.
Symptom:
The disease appears as circular reddish brown pustules which appear more commonly on the underside of the leaves, less abundant on pods and sparingly on stems.
When leaves are severely infected, both the surfaces are fully covered by rust pustules. The shriveling of grains is followed by defoliation results in yield losses.
Management:
Spray Mancozeb 2.5g/l of water.
5. How to Control Diseases of Blackgram?
1. Anthracnose (Colletotrichum lindemuthianum):
Symptoms:
The fungus attacks all aerial part parts and at any stage of plant growth. Symptoms are circular, black, sunken spots with dark center and bright red orange margins on leaves and pods. In severe infections, the affected parts wither off. Seedlings get blighted due to infection soon after seed germination. The pathogen survives on seed and plant debris. Disease spreads in the field through air-borne conidia. The disease is more sever in cool and wet seasons.
Management:
Seed treatment with Carbendazim 2g/kg. Remove and destruct plant debris. Spray Mancozeb 2g/lit or Carbendazim 0.5g/lit.
2. Bacterial Leaf Blight (Xanthomonas phaseoli):
Symptoms:
Many brown, dry and raised spots on the leaf surface. When the disease is severe several such spots coalesce, the leaves become yellow and fall off prematurely. The lower surface of the leaf appears red in colour due to the formation of raised spots. The stem and pods also get infected. The bacterium is seed-borne. Rain splashes play an important role in the development and spreading of the disease.
Management:
Use disease free seed. Destruction of debris and stubbles. Soak the seeds in 500 ppm Streptocycline solution for 30 min. before sowing followed by two sprays of Streptocycline combined with 3 g of Copper Oxychloride per litre at an interval of 12 days is recommended.
3. Cercospora Leaf Spot (Cercospora canescens):
Symptoms:
Spots produced are small, numerous in number with pale brown centre and reddish brown margin. Similar spots also occur on branches and pods. Under favourable environmental conditions, severe leaf spotting and defoliation occurs at the time of flowering and pod formation. The fungus is seed-borne and also survives on plant debris in the soil. High humidity favours disease development.
Management:
Intercrop with tall growing cereals and millets. Follow clean cultivation.
Use disease free seed. Maintain low crop population density and wide row planting. Mulching reduces the disease incidence resulting in increased yield. Spray with Carbendazim 0.5g/lit or Mancozeb 2.0g/lit at 30 days after sowing.
4. Powdery Mildew (Erysiphe polygoni):
Symptoms:
White powdery patches appear on leaves and other green parts which later become dull coloured. These patches gradually increase in size and become circular covering the lower surface also. When the infection is severe, both the surfaces of the leaves are completely covered by whitish powdery growth. Severely affected parts get shriveled and distorted.
In severe infections, foliage becomes yellow causing premature defoliation. The disease also creates forced maturity of the infected plants which results in heavy yield losses. The pathogen has a wide host range and survives in oidial form on various hosts in off- season. Secondary spread is through air-borne oidia produced in the season.
Management:
The seeds must be, sown early in the month of June to avoid early incidence of the disease on the crop. Powdery mildew could be controlled by spraying Carbendazim 1g/lit or Tridemorph 1 ml/lit.
5. Root Rot and Leaf Blight (Rhizoctonia solani):
Symptoms:
The pathogens cause seed decay, root rot, damping-off, seedling blight, stem canker and leaf blight in green gram. The disease occurs commonly at podding stage. In the initial stages, the fungus causes seed rot, seedling blight and root rot symptoms. The affected leaves turn yellow in colour and brown irregular lesions appear on leaves.
On coalescence of such lesions, big blotches are formed and the affected leaves start drying prematurely. Roots and basal portion of the stem become black in colour and the bark peels off easily. The affected plants dry up gradually. When the tap root of the affected plant is split open, reddening of internal tissues is visible. The pathogen is soil-borne.
Management:
Seed treatment with 4g Trichoderma viride formulation.
Symptoms:
The disease appears as circular reddish brown pustules which appear more commonly on the underside of the leaves, less abundant on pods and sparingly on stems. When leaves are severely infected, both the surfaces are fully covered by rust pustules.
Shriveling followed by defoliation resulting in yield losses.
Management:
Spray Mancozeb 2.5g/lit to control of the disease.
7. Stem Canker (Macrophomina phaseolina):
Symptoms:
In rice fallows, symptoms appear on 4 weeks old black gram crop as raised white cankers at the base of the stem. These enlarge gradually and turn as raised brown streaks spreading upwards. Plant becomes stunted and leaves dark green, mottled and reduced in size. Normal leaves on the affected plants drop suddenly and dry. Flowering and podding is greatly reduced.
Management:
Deep ploughing in summer. Follow crop rotation. Soil amendment with farm yard manure @ 12.5 tonnes/ha is helpful in reducing the incidence of the disease.
Destroy the diseased plant debris by burning of burying in the soil. Seed treatment with T. viride @4g/kg or P. fluorescens @ 10g/ kg of seed or Carbendazim or Thiram 2g/kg of seed. Spot drenching with Carbendazim 1g/lit or P. fluorescens/T. viride 2.5 kg/ha with 50 kg FYM.
8. Yellow Mosaic (Mungbean Yellow Mosaic Virus):
Symptoms:
The disease is more prevalent on black gram than green gram. Initially mild scattered yellow spots appear on young leaves. The next trifoliate leaves emerging from the growing apex show irregular yellow and green patches alternating with each other. Spots gradually increase in size and ultimately some leaves turn completely yellow. Infected leaves also show necrotic symptoms. Diseased plants are stunted, mature late and produce very few flowers and pods. Pods of infected plants are reduced in size and turn yellow in colour.
Management:
Grow resistant/tolerant varieties viz., Vamban 4, Vamban 5, etc. Grow seven rows of sorghum as border crop. Treat the seeds with Imidacloprid 70 WS @ 5mlAg to control vector. Rogue out MYMV infected plants early in the season to eliminate the source of inoculum. Give one foliar spray of systemic insecticide (Dimethoate @ 750 ml/ha) on 30 days after sowing.
9. Leaf Crinkle-Leaf Crinkle Virus:
Symptom:
The earliest symptoms appear on youngest leaves as chlorosis around some lateral veins and its branches near the margin. The leaves show curling of margin downwards. Some of the leaf shows the symptom of twisting. The veins show reddish brown discolouration on the under surface which also extends to the petiole. Plants showing symptoms within 5 weeks after sowing invariably remain stunted and majority of them die due to top necrosis within a week or two.
Plants infected in late stages of growth do not show severe curling and twisting of the leaves but show conspicuous venial chlorosis anywhere on the leaf lamina. The disease develops in the fields mainly through seed or rubbing of diseased leaves with the healthy ones.
Management:
Periodical removal of infected plants upto 45 days. Spray acephate 1g/lit or dimethoate 2 ml/lit to control vector.
6. How to Control Diseases of Sesame?
1. Bacterial Blight (Xanthomonas campestris pv. Sesame):
Symptom:
Plants of all stage are affected. Water soaked, small and irregular spots are formed on the leaves which later increases and turn brown, under favourable conditions. Leaves become dry and brittle, severely infected leaves defoliate.
Management:
Crop rotation. Use resistant variety like T-58. Early planting i.e., immediately after onset of monsoon. Destruction of crop residues. Steep the seed in agrimycin- 100 (250 ppm) or Streptocycline suspension (0.05%) for 30 minutes. Foliar spray of streptocycline (500 ppm) as soon as symptoms are noticed. Continue two more sprays at 15 days interval if necessary.
2. Cercospora Leaf Spot/White Spot (Cercospora sesami, C. sesamicola):
Symptom:
Disease appears as small, angular brown leaf spots of 3 mm diameter with gray centre and dark margin delimited by veins. In severity of the disease defoliation occurs. Under favourable conditions, the disease spreads to leaf petiole, stem and capsules producing linear dark coloured deep seated lesions.
Management:
Grow resistant/tolerant variety like TKG-21. Follow intercropping system of sesamum + pearl millet (3:1). Destruction of plant debris. Treat the seed with thiram or carbendazim 2g/kg. Three sprays with Mancozeb (0.25 %) as and when disease appears, at 15 days interval.
3. Damping Off/Root Rot (Macrophomina phaseolina):
Symptom:
The fungus attacks young seedling, their stem become water soaked soft and incapable of supporting the seedling which falls over and dies. On older seedlings elongated brownish black lesions appear which increase in length and width girdling the stem and plant dies.
Management:
Provide good drainage. Late planting. Destruction of diseased plants. Seed treatment with Thiram + Carbendazim (0.05%) 1:1 or @ 2g/kg. On appearance of the disease, drench soil with Carbendazim @ 1g/lit. Soil application with P. fluorescens or T. viride @ 2.5 kg/ha mixed with 50 kg/ha.
4. Powdery Mildew (Oidium sp., Sphaerotheca fuliginia, Leveillula sp.):
Symptom:
Small cottony spots appear on the infected leaves which gradually spread on the lamina. Defoliation of severely infected plant occurs before maturity.
Management:
Field sanitation. Destruction of crop residues. Follow intercropping system of sesamum + pearl millet (3:1). Use resistant variety RT-127.Foliar spray with of Wet- table sulphur (0.2%) as and when disease appears, at 10 days interval.
5. Sesamum Phyllody (Phytoplasma):
Symptom:
All floral parts are transformed into green leafy structures followed by abundant vein clearing in different flower parts. In severe infection, the entire inflorescences is replaced by short twisted leaves closely arranged on a stem with short internodes, abundant abnormal branches bend down. Finally, plants look like witches broom. If capsules are formed on lower portion of plant they do not yield quality seeds. Transmitted by the vector Orosius albicintus.
Management:
Use intercropping system, sesamum + pigeon pea (6:1). Destruction of diseased plants. Three spray of Dimethoate (0.03%) at 30, 40 and 60 days after sowing to control the vector.
6. Root Rot (Fusarium oxysporum f.sp. sesami):
Symptoms:
The plant gets infected at any stage of crop development. Symptoms are first visible in the lower leaves and then it progresses upwards. Yellowing, drooping and desiccation of leaves occur. In severe case, entire plant gets defoliated, bends down and ultimately dries up. Vascular bundles turn brown starting from root and gets extended up to tip.
Management:
Deep ploughing in summer. Follow crop rotation. Soil amendment with farm yard manure @ 12.5 tonnes/ha is helpful in reducing the incidence of the disease. Destroy the diseased plant debris by burning of burying in the soil. Seed treatment with T. viride @4g/kg or P. fluorescens @ 10g/ kg of seed or Carbendazim or Thiram 2g/kg of seed. Spot drenching with Carbendazim 1g/lit. Soil application of P. fluorescens/T. viride 2.5 kg/ha with 50 kg FYM.