India’s most important oilseed, grown across 4.7 million hectares of Gujarat, Andhra Pradesh, Tamil Nadu, and Rajasthan; the primary source of edible oil and protein cake for the western and southern Indian farmer.
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. Late Leaf Spot
(Cercosporidium personatum)
The Threat:
- Late leaf spot is the most consistently yield-damaging disease of groundnut in India.
- Dark brown, circular lesions with a yellow halo appear on the upper leaf surface from 45 days after sowing onward.
- The disease progresses rapidly up the canopy.
- As lesions multiply and coalesce, they cause complete defoliation from the bottom of the canopy upward.
- Defoliated plants cease photosynthesis, arresting pod fill and producing lightweight, oil-poor seeds.
- In humid kharif conditions, losses of 20–50% occur in unsprayed susceptible varieties.
The Solution:
- Begin a preventive fungicide programme at 45 days after sowing — do not wait for visible lesions, as the disease is already well established by then.
- Spray Mancozeb 75 WP (Contact Fungicide — Dithiocarbamate, FRAC Group M3) @ 2.5 g/litre or Chlorothalonil 75 WP (Contact Fungicide — Chloronitrile, FRAC Group M5) @ 2 g/litre every 10–14 days.
- Apply a total of 3–4 sprays through pod fill.
- Grow tolerant varieties recommended by ICAR-DGR, Junagadh — ICGS-44 and TAG-24 carry field-level resistance.
2. Drought at Pegging and Pod Fill
The Threat:
- Groundnut’s reproductive biology is unique — the fertilised flower bends downward and its elongating stalk (the peg) enters the soil, where the pod develops underground.
- This pegging process requires adequate soil moisture around the plant base.
- Drought during the 60–90 day window prevents peg entry, causes pod shell malformation (blistered, empty pods), and shrinks the developing seed.
- Soil moisture deficit at pod fill produces shrunken seeds with low oil content that are rejected at procurement.
The Solution:
- Give protective irrigation at pegging (50–55 days after sowing) and at pod fill (75–80 days) wherever irrigation is available — these are the two most yield-responsive irrigation timings in groundnut.
- Under rainfed conditions, earth-up soil around the plant base at pegging — heaping dry, loose soil around the plant collar — to cover pegs physically and retain local moisture.
- Practice conservation agriculture to maximise soil moisture retention through the pod fill period.
3. Tikka Disease / Early Leaf Spot
(Cercospora arachidicola)
The Threat:
- Early leaf spot appears from 30 days after sowing — earlier than late leaf spot — producing lighter brown, circular lesions with a bright yellow halo.
- In isolation, early leaf spot causes 10–15% losses through premature defoliation of the lower canopy.
- In combination with late leaf spot — which follows in the same field from 45 days onward — the two diseases work sequentially to strip the entire canopy from bottom to top.
- Combined management in a single fungicide programme is standard practice recommended by ICAR-DGR.
The Solution:
- Begin the combined leaf spot fungicide programme at 30 days after sowing with Mancozeb 75 WP (Contact Fungicide — Dithiocarbamate, FRAC Group M3) @ 2.5 g/litre.
- Continue sprays at 10–14 day intervals through the season as described for late leaf spot.
- Combined management of both diseases in a single programme is more economical and more effective than managing them separately.
4. Aflatoxin
(Aspergillus flavus)
The Threat:
- Aflatoxin contamination is the most serious quality and food safety issue in Indian groundnut production.
- Aspergillus flavus colonises drought-stressed or insect-damaged pods in the field and produces aflatoxins — potent carcinogens and immune suppressants — in both field-grown and stored pods.
- The contamination is invisible, odourless, and undetectable without laboratory analysis, yet it destroys the commercial value of entire consignments at export terminals and domestic processing plants.
- Regular consumption of aflatoxin-contaminated groundnut is associated with significantly elevated liver cancer risk.
The Solution:
- Biological Control:
- Trichoderma viride: Apply as a seed treatment (4g/kg) or soil application (2.5 kg/ha mixed with 50 kg Farm Yard Manure).
- Bacillus subtilis: Use as a seed treatment (10g/kg) to inhibit fungal growth.
- Soil Amendments:
- Gypsum: Apply 500 kg/ha at the flowering stage. Calcium helps develop strong shells, providing a physical barrier against fungal entry.
- Organic Cakes: Apply Neem cake or Castor cake (500 kg/ha) 7–15 days before sowing to reduce soil-borne fungal populations.
- Agronomic Practices:
- Drought Management: Provide supplemental irrigation during the pod-filling stage, as moisture stress weakens pods and invites infection.
- Resistant Varieties: Use cultivars identified for lower susceptibility, such as J-11, ICG 1471, or ICGV 88145
- Harvest promptly at crop maturity — delayed harvest allows post-maturity soil infection.
- Dry pods to below 9% moisture before storage.
- Use hermetic storage bags (Physical Storage Management — PICS bags) that deny the fungus oxygen for growth and toxin production.
5. Groundnut Rosette Virus
(transmitted by Aphis craccivora)
The Threat:
- Groundnut rosette is the most damaging virus disease of groundnut in India.
- The virus causes severe stunting, leaf chlorosis, and mottling, and completely prevents pod set in infected plants — a plant infected before flowering produces zero pods.
- The virus is transmitted by the groundnut aphid Aphis craccivora in a persistent manner.
- Primary inoculum comes from infected wild legume hosts at the field margins, making early-season aphid management — before the population moves from wild hosts into the crop — the critical management window.
- In epidemic years, losses reach 10–40%.
The Solution:
- Sow early — May–June in kharif — before peak aphid populations build up on wild legume hosts.
- Treat seed with Imidacloprid 70 WS (Systemic Insecticide — Neonicotinoid, IRAC Group 4A) @ 7 g/kg to protect against early-season aphid colonisation.
- Rogue and destroy symptomatic plants within 30 days of sowing — symptomatic plants are both non-productive and are aphid-virus amplification centres.
- Remove weed legume hosts from field margins before sowing.
Ph.D. in Agricultural Engineering.