Introduction

Black gram, known scientifically as Vigna mungo, is a crucial pulse crop grown extensively in various parts of Asia. However, its cultivation is often challenged by a range of diseases that can significantly impact yield and quality. Understanding these diseases, their symptoms, and effective management strategies is essential for farmers to safeguard their crops and ensure sustainable production. In this comprehensive guide, we delve into the common diseases of black gram, offering insights into identification, prevention, and treatment methods that empower farmers to protect their harvests and maximize yields.

Powdery mildew :

Causal organism : Erysiphe polygoni

Symptoms:

White powdery spots appear on the leaves.

Severe infection occurs during flowering and pod development stage.

The plant assumes greyish white appearance; leaves turn yellow and finally shed.

Management:

Remove and destroy infected plant debris. 

Spray Carbendazim 500g or Wettable sulphur 2kg at the initiation of disease and repeat 15 days later. 

Spray Dinocap 0.05%.

Anthracnose:

Causal organism: Colletotrichum lindemuthianum

Symptoms:

Fungus produces dark brown to black sunken lesions on the hypocotyl area and cause death of the seedlings .

Small angular brown lesions appear on leaves which later become greyish white centre with dark brown or reddish margin. 

Minute water soaked lesion appears on pods and becomes brown and depressed spot with dark centre with bright red margin.

Management: 

Remove and destroy infected plant debris.

Treat the seeds with Carbendazim at 2g/kg.

Spray Chlorothalonil 1kg or Mancozeb 2kg/ha soon after appearance of disease and repeat after 15 days.

Leaf Spot :

Causal organism: Cercospora canescens

Symptoms:

Small , Circular spots develop on leaves with grey centre and brown margin. 

In severe cases defoliation occurs .

Powdery growth of the fungus may be seen on centre of the spots.

Management: 

Remove and burn infected plant debris. 

Spray Chlorothalonil 1kg/ha or Mancozeb at 2kg/ha.

Rust :

Causal organism: Uromyces phaseoli var typica

Symptoms:

Rust pustules are mostly seen on leaves ,rarely on petioles ,stem and

pods.Small,round ,reddish brown uredosori developed on lower surface of leaves.

In late season ,teliosori appear on the leaves which are linear and dark brown in colour.

Intense pustule formation causes drying and shedding of leaves.

Management:

Remove infected plant debris and destroy.

Spray Mancozeb 2kg or Propiconazole 1L/ha , immediately on the set of disease and repeat after 15 days.

Dry root rot :

Causal organism: Rhizoctonia bataticola

Symptoms:

Initial stage , yellowing and drooping of the leaves. Falling of leaves later and plant dies within a week. 

Dark brown lesions seen on stem and bark shows shredding symptom.

Affected plants can be easily pulled out leaving dried ,rotten root portions in the soil . 

Rotten tissues contain large number of black minute sclerotia.

Management:

Treat the seeds with Carbendazim + thiram at 2g/kg .

Pellet the seeds with Trichoderma viridae at 4g/kg or pseudomonas fluorescens @10g of seed.

Apply farm yard manure or green leaf manure (Gliricidia maculata) at 10t/ha or neem cake at 150kg /ha.

Leaf crinkle disease:

Causal organism: Urd bean leaf crinkle virus (ULCV)

Symptoms:

Curling and crinkling of the tips of leaflets and increase in leaf area.

Crinkling and rugosity in older leaves becomes severe and leaves thickened. 

Infected plant gives a stunted and bushy appearance.

Flowering is delayed ,if inflorescence is malformed with small size flower buds and fails to open.

Management :

Use increased seed rate (25 kg / ha )

Rogue out diseased plants at weekly interval upto 45 days after sowing.

Remove weed hosts periodically.

Spray methyl demeton on 30 and 40 days after sowing at 500ml/ha.

Conclusion

Safeguarding black gram from diseases is crucial for ensuring healthy yields and sustainable farming practices. By understanding the common diseases like powdery mildew, root rot, and leaf spot, farmers can implement timely interventions such as crop rotation, proper irrigation management, and the use of resistant varieties. Integrated pest management techniques also play a pivotal role in minimizing disease impact while promoting soil health and crop vitality. With proactive measures and knowledge-driven practices, farmers can effectively manage diseases in black gram, contributing to enhanced productivity and profitability in agriculture.