A short-duration (60–65 day) summer and kharif pulse grown across 3.5 million hectares, providing India’s fastest-growing protein crop and the most rapidly expanding pulse in the summer cropping system.
Mung bean : 5 Major Threats and Their Control
For guidance only. Does not replace local expert advice. Check region-specific recommendations with your nearest KVK or State Agriculture Department before buying seeds, fertilizers, or pesticides.
1. Yellow Mosaic Virus
(MYMV — Mungbean Yellow Mosaic Virus)
The Threat:
- Yellow mosaic virus produces a bright, unmistakable yellow-green mosaic pattern on leaves.
- Infected plants cease vegetative growth and pod development entirely — they remain alive but functionally sterile.
- The virus is transmitted by the whitefly Bemisia tabaci in a persistent manner — a single whitefly can carry and transmit the virus for weeks.
- The disease spreads most rapidly in warm, dry conditions when whitefly populations peak and natural enemies are suppressed.
- In epidemic years losses reach 70% and cause near-total crop failure.
The Solution:
- Grow recommended virus-resistant varieties that carry useful levels of MYMV resistance.
- Treat seed with Imidacloprid 70 WS (Systemic Insecticide — Neonicotinoid) @ 7 g/kg to manage early-season whitefly (the vector) during the critical first 3 weeks.
- Key point: spraying after yellow mosaic symptoms appear is completely useless — the virus is already within the plant’s vascular system and cannot be removed.
- The spray must be applied as a vector management measure BEFORE infection, not as a response to visible symptoms.
2. Cercospora Leaf Spot
(Cercospora canescens)
The Threat:
- Cercospora leaf spot produces brown, circular lesions with a yellow halo on both leaf surfaces.
- Symptoms begin on older leaves and progress upward through the canopy.
- In humid kharif conditions, multiple lesions merge and cause complete defoliation of the lower and mid canopy, reducing the total photosynthetic area available for pod development and seed fill.
- Early and severe infection can reduce both pod number and seed weight simultaneously, causing 10–20% losses.
- The disease is favoured by the dense, humid canopy of high-population, broadcast-sown moong fields.
The Solution:
- Maintain adequate plant spacing — 30 × 10 cm — for canopy air circulation that reduces leaf wetness duration.
- At first symptom appearance on lower leaves, spray Carbendazim 50 WP (Systemic Fungicide — Benzimidazole) @ 1 g/litre or Mancozeb 75 WP (Contact Fungicide — Dithiocarbamate) @ 2.5 g/litre.
- Rotate between systemic and contact fungicides in successive sprays to prevent fungicide resistance development.
3. Pod Borer
(Helicoverpa armigera)
The Threat:
- Helicoverpa larvae bore into developing moong pods between 35–50 days after sowing and consume the grain inside.
- Moong pods are thin-walled and offer less mechanical resistance than chickpea pods, making borer damage easier to inflict but also easier to detect through visible entry holes.
- Losses of 10–20% occur in kharif moong grown near chickpea, cotton, or maize where large Helicoverpa populations build up and spill over.
- Correct scouting — counting larvae per metre of row, not per plant — is essential for threshold-based spray decisions.
The Solution:
- Spray HaNPV (Biological Insecticide — Baculovirus) @ 250 Larval Equivalents/ha at first larval detection.
- Apply Indoxacarb 14.5 SC (Systemic Insecticide — Oxadiazine) @ 0.5 ml/litre at threshold (2 larvae per metre row).
- Install pheromone traps (Semiochemical) @ 3 per hectare for monitoring.
- Maintain a minimum 7-day pre-harvest interval for all chemical applications.
4. Drought / Heat Stress in Summer Season
(Helicoverpa armigera)
The Threat:
- Summer-grown moong (zaid crop) faces the most thermally extreme growing conditions of any pulse in India.
- Temperatures exceed 35°C throughout the life cycle, combined with dry, desiccating winds that accelerate evapotranspiration and flower drop.
- Unlike kharif moong, the zaid crop is entirely irrigation-dependent, and even a single missed irrigation at flowering or pod fill can reduce yield by 20–30%.
- Flower drop under heat stress is often mistaken for “disease” by growers, leading to unnecessary fungicide applications that worsen the problem.
The Solution:
- Grow recommended varieties specifically bred for summer cultivation – for high-temperature tolerance and short-duration flowering.
- Irrigate at critical growth stages — flowering and pod fill — using short, frequent light irrigations rather than heavy infrequent ones.
- Mulch the soil surface with wheat straw @ 3–4 t/ha to moderate soil temperature and reduce evaporation from the root zone.
5. Powdery Mildew
(Erysiphe polygoni)
The Threat:
- Powdery mildew appears as a white, powdery coating on leaves, petioles, and pods in the cool post-monsoon moong crop.
- Typically occurs in September–November sown crops.
- Thrives under dry conditions with moderate humidity and temperatures between 20–25°C, unlike fungal diseases that require wet conditions.
- Severe infection covers the photosynthetic surface and pod surface, reducing seed fill and pod quality.
- Losses of 5–10% occur in susceptible varieties.
The Solution:
- Spray wettable Sulphur 80 WP (Contact Fungicide — Inorganic Sulphur) @ 3 g/litre at first symptom appearance; effective under conventional and organic systems.
- Maintain adequate plant spacing for canopy air circulation.
- Grow tolerant varieties where powdery mildew is a recurring problem in the post-kharif season.
Additional Reads
Ph.D. in Agricultural Engineering.