Major Pests and Diseases of Green Gram and Their Integrated Management

1. Introduction

Green gram (Vigna radiata), also known as mung bean, is one of the most important pulse crops of India. It is widely cultivated during Kharif, Rabi, and summer seasons across diverse agro-climatic zones, including rainfed and irrigated conditions.

Importance of Green Gram in Indian Agriculture

• Plays a vital role in nutritional security due to high protein content
• Improves soil fertility through biological nitrogen fixation
• Short duration crop (60–70 days), suitable for crop rotation and intercropping
• Low water requirement compared to cereals
• Important source of income for small and marginal farmers

Nutritional and Economic Significance

• Protein: 22–24%
• Rich in lysine, vitamins, minerals, and dietary fiber
• High market demand for dal, sprouts, and processed foods
• Export potential due to increasing global demand

Yield Losses Due to Pests and Diseases

Despite its importance, green gram productivity in India (≈ 500–600 kg/ha) is much lower than its potential. Major reasons include:

• Severe infestation of insect pests
• Frequent outbreaks of viral and fungal diseases
• Lack of timely diagnosis and improper pesticide use

Estimated yield losses:

• Insect pests: 30–40%
• Diseases (especially YMV): up to 80% under severe conditions

Hence, adopting an Integrated Pest and Disease Management (IPM & IDM) approach is essential for sustainable and profitable green gram cultivation.

2. Major Insect Pests of Green Gram

2.1 Aphids

Common name: Aphids
Scientific name: Aphis craccivora

Identification & Damage Symptoms

• Small, soft-bodied, green to black insects on tender shoots and leaves
• Suck sap → leaves curl, turn yellow, and plant growth is stunted
• Secrete honeydew → development of sooty mould
• Act as vectors of viral diseases

Favorable Conditions

• Cool and dry weather
• Dense crop canopy
• Excess nitrogen application

Economic Threshold Level (ETL)

• 10–15 aphids per 10 cm terminal shoot

Integrated Management

Cultural Practices

• Avoid excess nitrogen
• Maintain proper plant spacing
• Remove weed hosts (especially legumes)

Mechanical Methods

• Early stage: strong water spray to dislodge aphids
• Removal of heavily infested shoots

Biological Control

• Ladybird beetles (Coccinella spp.)
• Lacewings (Chrysoperla carnea)
• Neem-based formulations

Chemical Control (Need-based)

• Imidacloprid 17.8 SL @ 0.3 ml/litre
• Thiamethoxam 25 WG @ 0.25 g/litre
• Spray interval: 10–14 days

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2.2 Whitefly (Vector of Yellow Mosaic Virus)

Scientific name: Bemisia tabaci

Identification & Damage Symptoms

• Tiny white insects on the underside of leaves
• Yellowing, leaf curling, reduced vigor
• Transmission of Yellow Mosaic Virus (YMV)

Favorable Conditions

• Warm and dry climate
• Continuous pulse cultivation
• Presence of alternate hosts

ETL

• 5–10 adults per leaf

Integrated Management

Cultural Practices

• Timely sowing (avoid peak whitefly period)
• Removal of infected plants
• Use of resistant varieties

Mechanical Methods

• Yellow sticky traps (10–12/acre)

Biological Control

• Encarsia and Eretmocerus parasitoids
• Neem oil 0.3%

Chemical Control

• Imidacloprid 17.8 SL @ 0.3 ml/litre
• Acetamiprid 20 SP @ 0.2 g/litre

⚠️ Avoid repeated use of same insecticide group

2.3 Thrips

Scientific name: Thrips palmi

Damage Symptoms

• Silvery streaks on leaves
• Leaf curling and drying
• Flower drop in severe cases

Favorable Conditions

• Hot and dry weather
• Moisture stress

ETL

• 5–8 thrips per leaf

Integrated Management

• Timely irrigation
• Blue sticky traps
• Neem oil 3 ml/litre
• Spinosad 45 SC @ 0.3 ml/litre

2.4 Jassids (Leafhoppers)

Scientific name: Empoasca kerri

Symptoms

• Yellowing at leaf margins (“hopper burn”)
• Downward curling of leaves
• Reduced photosynthesis

Management

• Resistant varieties
• Balanced fertilization
• Thiamethoxam 25 WG @ 0.25 g/litre

2.5 Stem Fly

Scientific name: Ophiomyia phaseoli

Damage Symptoms

• Maggots bore into stem
• Wilting and drying of young plants
• Swollen stems with tunneling marks

Favorable Conditions

• Early crop stage (10–30 DAS)

Integrated Management

• Early sowing
• Seed treatment with Imidacloprid 600 FS @ 5 ml/kg seed
• Soil application of neem cake

2.6 Leaf Miner

Scientific name: Liriomyza trifolii

Symptoms

• Zig-zag mines on leaves
• Reduced photosynthetic area

Management

• Removal of mined leaves
• Neem oil spray
• Abamectin 1.9 EC @ 0.5 ml/litre

2.7 Pod Borer

Scientific name: Helicoverpa armigera

Damage Symptoms

• Larvae feed on flowers and pods
• Circular holes on pods
• Direct yield loss

ETL: 1 larva per plant

Integrated Management

Cultural

• Deep summer ploughing
• Intercropping with sorghum or marigold

Mechanical

• Handpicking larvae
• Pheromone traps (5/acre)

Biological

• Helicoverpa NPV @ 250 LE/ha
• Trichogramma egg parasitoids

Chemical

• Emamectin benzoate 5 SG @ 0.4 g/litre
• Chlorantraniliprole 18.5 SC @ 0.3 ml/litre

3. Major Diseases of Green Gram

3.1 Yellow Mosaic Virus (YMV)

Causal organism: Virus (transmitted by whitefly)

Symptoms

• Yellow and green mosaic patches
• Reduced flowering and pod formation
• Severe stunting

Mode of Spread

• Whitefly (Bemisia tabaci)

Yield Impact

• 30–80%, severe outbreaks may cause complete crop failure

Integrated Disease Management

Resistant Varieties

• IPM 02-3, SML 668, PDM 139

Cultural

• Early sowing
• Rogue out infected plants
• Weed control

Chemical (Vector Control)

• Imidacloprid 17.8 SL @ 0.3 ml/litre

3.2 Cercospora Leaf Spot

Causal organism: Cercospora canescens

Symptoms

• Circular brown spots with yellow halo
• Defoliation under severe infection

Favorable Conditions

• High humidity and moderate temperature

Management

• Seed treatment with Carbendazim @ 2 g/kg seed
• Mancozeb 75 WP @ 2.5 g/litre

3.3 Powdery Mildew

Causal organism: Erysiphe polygoni

Symptoms

• White powdery growth on leaves
• Premature leaf drop

Management

• Resistant varieties
• Wettable sulphur @ 2 g/litre
• Hexaconazole 5 EC @ 1 ml/litre

3.4 Root Rot & Collar Rot

Causal organisms: Rhizoctonia solani, Macrophomina phaseolina

Symptoms

• Seedling death
• Black lesions at collar region

Management

• Seed treatment with Trichoderma viride @ 4 g/kg seed
• Avoid waterlogging
• Crop rotation

3.5 Anthracnose

Causal organism: Colletotrichum lindemuthianum

Symptoms

• Dark sunken lesions on stem and pods
• Poor seed quality

Management

• Disease-free seed
• Carbendazim + Mancozeb @ 2 g/litre

3.6 Leaf Crinkle Disease

Cause: Virus

Symptoms

• Crinkled, distorted leaves
• Bushy growth and sterility

Management

• Rogue out infected plants
• Control vectors (aphids)
• Use healthy seed

4. Preventive Measures & Best Agronomic Practices

• Use certified disease-free seed
• Seed treatment is mandatory
• Crop rotation with cereals
• Timely sowing (avoid late Kharif sowing)
• Recommended spacing (30 × 10 cm)
• Balanced fertilizer application (avoid excess nitrogen)

5. Organic & Eco-Friendly Management Options

• Neem oil (0.3%)
• Neem seed kernel extract (NSKE 5%)
• Trichoderma, Pseudomonas fluorescens
• Cow urine-based botanical sprays
• Conservation of natural enemies

6. Stage-wise Spray Schedule (Indicative)

7. Conclusion

Green gram is a highly rewarding pulse crop, but its success largely depends on early diagnosis of pests and diseases and adoption of an integrated management approach. Over-dependence on chemicals not only increases costs but also leads to resistance and ecological imbalance.

Key Advice to Farmers

• Monitor fields regularly
• Follow IPM & IDM principles
• Use chemicals only when ETL is crossed
• Prefer eco-friendly and biological options
• Seek guidance from agriculture officers when needed

By adopting scientifically proven, integrated practices, farmers can achieve higher yields, better quality produce, and sustainable green gram cultivation.