A rabi pulse grown across 1.5 million hectares of MP, UP, and West Bengal, providing affordable high-quality protein and iron to the Indian diet, particularly in eastern India.
5 Major Threats and Their Control
For educational purposes only. Recommended crop varieties are location-specific. Always verify chemical and variety recommendations with your local KVK or State Agriculture Department.
1. Rust
(Uromyces fabae)
The Threat:
- Lentil rust develops in the cool, humid conditions of late February and March — precisely when pods are filling and grain weight is being determined.
- Brown, round pustules erupt on leaves and pods, releasing urediniospores that spread rapidly through the crop canopy under humid conditions.
- As the infection intensifies, it causes premature leaf fall that terminates the grain-fill period early, producing small, lightweight seeds with poor yield and nutritional value.
- Losses of 10–30% are documented in epidemic years when February–March weather is unusually wet.
The Solution:
- Grow rust-resistant varieties recommended by ICAR-IIPR — PL-406, Sehore-74-3, and K-75 are currently recommended for north Indian conditions.
- At the first appearance of pustules on lower leaves, spray Mancozeb 75 WP (Contact Fungicide — Dithiocarbamate, FRAC Group M3) @ 2.5 g/litre, and repeat 10 days later.
- Monitor from mid-February onward in high-risk districts of Bihar and MP.
- A second variety-based line of protection — growing varieties with combined rust and stemphylium resistance — is increasingly recommended by ICAR-IIPR.
2. Stemphylium Blight
(Stemphylium botryosum)
The Threat:
- Stemphylium blight has emerged as a major disease of lentil in Bihar and West Bengal over the past decade, now achieving epidemic status in some districts of the Gangetic plain.
- It produces dark brown, irregular lesions on leaves, stems, and pods that coalesce and cause rapid, complete defoliation of the mid and upper canopy in humid, dense-sown crops.
- The disease is seed-borne in its initial introduction to new fields, but spreads through airborne conidia within the season.
- Its rapid emergence is linked to the adoption of high-yielding, susceptible varieties combined with dense planting practices.
The Solution:
- Avoid dense sowing — maintain 25 cm row spacing to allow canopy air circulation, which reduces the leaf wetness duration essential for spore germination.
- Treat seed with Iprodione 25 WP (Contact Fungicide — Dicarboximide, FRAC Group 2) @ 2 g/kg.
- Spray Iprodione 25 WP @ 1.5 g/litre or Chlorothalonil 75 WP (Contact Fungicide — Chloronitrile, FRAC Group M5) @ 2 g/litre at first symptom appearance, with a second spray 10 days later in high-humidity seasons.
3. Pod Borer
(Helicoverpa armigera)
The Threat:
- The same caterpillar that devastates chickpea migrates into adjacent lentil fields at the pod-filling stage — particularly in districts of MP and UP where both crops are grown in proximity.
- In lentil, the intensity is generally lower than in chickpea because lentil’s pod architecture and growth habit are less preferred by the pest, but in outbreak years, losses of 8–15% occur.
- The larva bores into pods and consumes developing seeds, leaving empty pods that are difficult to distinguish from healthy ones until threshing.
The Solution:
- Spray NSKE (Neem Seed Kernel Extract) 5% (Botanical Insecticide — Biopesticide) @ 5% at first larval detection — an effective, farmer-producible alternative.
- Install pheromone traps (Semiochemical) @ 3 per hectare for adult monitoring.
- Apply Malathion 50 EC (Contact Insecticide — Organophosphate, IRAC Group 1B) @ 1 ml/litre at threshold (2 larvae per metre row) if biological control is insufficient.
- Maintain a 7-day pre-harvest interval for all chemical applications on lentil.
4. Cold Stress at Flowering
The Threat:
- Late-sown lentil — sown after November 20 in north India — flowers during the coldest fortnight of January, when minimum temperatures regularly fall below 4–5°C and near-frost conditions occur in fog-affected plains.
- Flower drop and pod abortion are triggered by cold-induced pollen sterility, reducing the number of pods per plant by 30–50% compared to timely-sown crops.
- This is an entirely calendar-preventable loss — the cold window is predictable, and adjusting sowing date to allow flowering before the frost period eliminates the risk without any input cost.
The Solution:
- Sow by the second week of November to allow flowering by late December, before the hardest frost window of January 5–20 in north India. This single calendar adjustment is cost-free and completely effective.
- Grow cold-tolerant varieties recommended by ICAR-IIPR — Pant L-406 is specifically developed for late-sown, cold-risk situations.
- In hill situations above 1,500 m where early sowing is not possible, apply anti-transpirant (Physical Crop Protection Agent) spray before a predicted frost event.
5. Iron Chlorosis
The Threat:
- Interveinal chlorosis of young leaves — new leaves emerging yellow with green veins — occurs on the calcareous, high-pH alluvial soils, where soil iron is chemically fixed in unavailable ferric forms.
- In lentil, iron deficiency:
- Reduces chlorophyll content.
- Impairs nitrogen-fixing Rhizobium bacteria in root nodules (which require iron for nitrogenase enzyme function).
- Reduces overall plant vigour and disease resistance.
- The dual impact on photosynthesis and nitrogen fixation makes iron chlorosis particularly damaging for a leguminous crop.
The Solution:
- Spray ferrous sulphate (FeSO₄) 0.5% (Micronutrient Fertiliser) @ 5 g/litre at 14-day intervals from first symptom appearance.
- Apply FeEDTA chelate (Chelated Micronutrient Fertiliser) @ 5 kg/ha to the soil for longer-lasting correction — chelated iron remains in plant-available form across a wider soil pH range than inorganic sulphate.
- Incorporate FYM or green manure to chelate soil iron naturally and buffer soil pH.
- Use Rhizobium inoculant seed treatment with lentil sowing for maximum nitrogen fixation performance.
Ph.D. in Agricultural Engineering.