: Pulses :: Greengram

1. Anthracnose: Colletotrichum lindemuthianum
2. Bacterial Leaf Blight: Xanthomonas phaseoli
3. Cercospora leaf spot: Cercospora canescens
4. Leaf crinkle disease: Leaf Curl Virus
5. Macrophomina Blight: Macrophomina phaseolina
6. Yellow mosaic : Mungbean yellow mosaic virus
7. Powdery Mildew: Erysiphe polygoni
8. Root Rot and Leaf Blight: Rhizoctonia solani
9. Rust: Uromyces phaseoli                                                                                                                                 

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 increase yield. Cercospora leaf spot can be controlled with Carbendazim 0.5g/lit.or Mancozeb 2.0g/lit.

4. Leaf crinkle disease: Leaf Curl 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 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 any where 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

Symptom                                                                               

• 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

Symptom Initially mild scattered yellow spots appear on young leaves. 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. The disease is transmitted by the whitefly, Bemisia tabaci.

Management

• Grow resistant varieties to yellow mosaic.
• Grow seven rows of sorghum as border crop
• Treat seeds with Imidacloprid 70 WS @ 5ml/kg 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.

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

Symptom 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.
• 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.

9. Rust :Uromyces phaseoli

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.
• Shriveling followed by defoliation resulting in yield losses.

Management

• Spray Mancozeb 2.5g /lit