Major Pests and Diseases of Black Gram (Urad) and Their Integrated Management

Introduction

Importance of Black Gram in Indian Agriculture

Black gram (Vigna mungo), popularly known as Urad, is one of the most important pulse crops cultivated in India. It plays a vital role in ensuring nutritional security, soil health, and farm income, especially for small and marginal farmers. India is the largest producer and consumer of black gram, with major cultivation in states like Andhra Pradesh, Telangana, Maharashtra, Madhya Pradesh, Uttar Pradesh, Tamil Nadu, Karnataka, and Odisha.

Black gram fits well in multiple cropping systems such as:

• Kharif
• Rabi
• Summer
• Rice fallows
• Intercropping and relay cropping systems

Nutritional and Economic Value

Black gram seeds are rich in:

• Protein (22–24%)
• Carbohydrates
• Iron and calcium
• Vitamins and dietary fiber

It is widely used for dal, papad, idli, dosa, and vada, creating strong market demand and stable prices.

Major Constraints Affecting Productivity

Despite its importance, black gram productivity in India remains low due to:

• Heavy incidence of insect pests
• Devastating viral and fungal diseases
• Indiscriminate pesticide use
• Poor adoption of Integrated Pest and Disease Management (IPDM)

Among all constraints, pests and diseases alone can cause 30–80% yield loss, making scientific crop protection essential.

Major Insect Pests of Black Gram

1. Aphids

Scientific Name: Aphis craccivora

Identification & Symptoms

• Small, soft-bodied green or black insects
• Colonies on tender shoots, leaves, and flowers
• Leaves curl downward and become yellow
• Honeydew secretion leads to sooty mould
• Acts as a vector for viral diseases

Crop Stage Affected

• Seedling to flowering stage

Economic Threshold Level (ETL)

• 10–15 aphids per top 10 cm shoot

Favorable Conditions

• Cool and dry weather
• Cloudy conditions
• Excess nitrogen fertilization

Integrated Management

Cultural Methods

• Avoid excess nitrogen
• Early sowing
• Balanced fertilization

Mechanical Methods

• Yellow sticky traps (10–12/acre)

Biological Control

• Ladybird beetles (Coccinella spp.)
• Lacewings (Chrysoperla carnea)

Chemical Control

• Imidacloprid 17.8 SL @ 0.3 ml/L
• Thiamethoxam 25 WG @ 0.25 g/L

Resistance Management

• Avoid repeated spraying of neonicotinoids
• Rotate with different insecticide groups

2. Whiteflies

Scientific Name: Bemisia tabaci

Symptoms

• Yellowing and curling of leaves
• Stunted growth
• Transmission of Yellow Mosaic Virus (YMV)

Crop Stage

• Seedling to pod formation

ETL

• 5–10 adults per plant

Favorable Conditions

• High temperature
• Low rainfall

Integrated Management

Cultural

• Use healthy seeds
• Remove weed hosts

Mechanical

• Yellow sticky traps

Biological

• Encarsia parasitoids

Chemical

• Acetamiprid 20 SP @ 0.2 g/L
• Flonicamid 50 WG @ 0.3 g/L

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3. Thrips

Scientific Name: Thrips tabaci

Symptoms

• Silvery streaks on leaves
• Leaf curling and drying
• Reduced flowering

ETL

• 8–10 thrips per leaf

Management

• Neem oil 3% @ 3 ml/L
• Spinosad 45 SC @ 0.3 ml/L

4. Leafhoppers (Jassids)

Scientific Name: Empoasca kerri

Symptoms

• Yellowing at leaf margins
• Leaf cupping and drying

Chemical Control

• Thiamethoxam 25 WG @ 0.25 g/L

5. Tobacco Caterpillar

Scientific Name: Spodoptera litura

Symptoms

• Skeletonization of leaves
• Severe defoliation

ETL

• 1 egg mass or 5 larvae/m²

Integrated Management

• Deep summer ploughing
• Pheromone traps (5/acre)
• NPV @ 250 LE/ha
• Emamectin benzoate 5 SG @ 0.4 g/L

6. Pod Borer

Scientific Name: Helicoverpa armigera

Symptoms

• Bores into pods
• Feeds on developing seeds

ETL

• 1 larva per plant

Chemical Control

• Chlorantraniliprole 18.5 SC @ 0.3 ml/L
• Indoxacarb 14.5 SC @ 1 ml/L

7. Hairy Caterpillar

Scientific Name: Amsacta albistriga

Management

• Light traps
• Mechanical collection
• Lambda-cyhalothrin 5 EC @ 1 ml/L

8. Stem Fly

Scientific Name: Ophiomyia phaseoli

Symptoms

• Wilting of seedlings
• Tunnel inside stem

Management

• Seed treatment with Imidacloprid 600 FS @ 5 ml/kg seed

Major Diseases of Black Gram

1. Yellow Mosaic Virus (YMV)

Causal Agent: Virus transmitted by whitefly

Symptoms

• Yellow patches on leaves
• Stunted growth
• Poor pod setting

Favorable Conditions

• High whitefly population
• Warm climate

Integrated Disease Management

• Resistant varieties: PU 31, LBG 623
• Early sowing
• Vector control
• Rogue infected plants

2. Powdery Mildew

Causal Organism: Erysiphe polygoni

Symptoms

• White powdery growth on leaves
• Premature leaf drop

Chemical Control

• Wettable sulphur 80 WP @ 2 g/L
• Hexaconazole 5 EC @ 1 ml/L

3. Cercospora Leaf Spot

Causal Organism: Cercospora canescens

Symptoms

• Brown circular spots
• Defoliation

Management

• Mancozeb 75 WP @ 2.5 g/L
• Carbendazim 50 WP @ 1 g/L

4. Anthracnose

Causal Organism: Colletotrichum lindemuthianum

Symptoms

• Dark sunken lesions on pods
• Seed discoloration

Management

• Seed treatment with Carbendazim @ 2 g/kg seed

5. Root Rot & Collar Rot

Causal Organism: Rhizoctonia, Fusarium

Management

• Well-drained soils
• Seed treatment with Trichoderma @ 4 g/kg seed

6. Leaf Crinkle Disease

Symptoms

• Thickened, crinkled leaves
• Deformed flowers

Management

• Use disease-free seeds
• Vector control
• Field sanitation

Integrated Pest and Disease Management (IPDM) Strategy

• Use certified seeds
• Adopt crop rotation
• Timely sowing
• Regular monitoring
• ETL-based pesticide use
• Promote bio-agents and botanicals

Seasonal Crop Protection Calendar for Black Gram

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Safe Pesticide Use & Farmer Advisory

• Follow recommended dose only
• Avoid tank mixing without compatibility
• Use protective clothing
• Observe waiting period before harvest

Conclusion

Effective management of black gram pests and diseases requires a holistic IPM and IDM approach rather than sole dependence on chemicals. Adoption of resistant varieties, biological control, cultural practices, and need-based pesticide application can significantly reduce crop losses, input costs, and environmental hazards.

Sustainable black gram production is possible only through eco-friendly, economical, and scientifically planned crop protection strategies.

Frequently Asked Questions (FAQs)

Q1. What is the most dangerous disease in black gram?
Yellow Mosaic Virus (YMV) causes the highest yield loss.

Q2. Can we mix fungicides and insecticides?
Only compatible products should be mixed after a jar test.

Q3. Which bio-agent is best for root rot?
Trichoderma viride or T. harzianum.

Q4. How many sprays are needed in black gram?
Usually 2–3 need-based sprays under IPM.