MAIZE

Now India’s third most important cereal, grown across Karnataka, Andhra Pradesh, Bihar, and Rajasthan in both kharif and rabi seasons — covering 12.83 million hectares (kharif 9.82 mha, rabi 3.0 mha).

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. Fall Armyworm

(Spodoptera frugiperda)

The Threat:

  • The fall armyworm hides inside the whorl of young maize plants and feeds protected from rain and spray contact, voraciously consuming leaf tissue before moving toward the cob.
  • Early infestations cause scraping marks on inner whorl leaves and papery windows where larvae have eaten through leaf tissue.
  • Severe infestation at this stage can destroy 20–50% of a crop.
  • Populations spread rapidly due to the adult moth’s long-distance migration capacity.
  • Early detection through systematic scouting is the most critical management step.
  • Late management after larvae enter the stalk or ear is much less effective.

The Solution:

  • Monitoring:
    • Install pheromone traps (Semiochemical / Lure — for adult male monitoring) @ 12 per hectare from 7 days after emergence.
    • Check whorls of at least 20 plants per acre daily for scraping, papery windows, or frass deposits.
  • Cultural Control:
    • Deep summer ploughing (May–June) destroys overwintering pupae in the soil.
    • Intercropping maize with cowpea reduces larval movement between plants.
    • Use “push-pull” technology — intercropping with Desmodium uncinatum (repels moths) and planting Napier grass on field borders as a trap crop.
  • Biological Control:
    • Apply Metarhizium anisopliae or Beauveria bassiana (Biopesticide — Entomopathogenic Fungi) as a whorl spray at first larval detection.
    • Release Telenomus remus (Egg Parasitoid — Biological Control Agent, recommended by ICAR-NBAIR) where available.
    • These agents are safe for pollinators, natural enemies, and vertebrates.
  • Chemical Control — Early Stage (15–20 days after emergence):
    • Azadirachtin 1500 ppm (Botanical Insecticide — Neem-based Biopesticide) @ 2.5 litres/ha
    • Chlorantraniliprole 18.5 SC (Systemic Insecticide — Diamide, IRAC Group 28) @ 200 ml/ha
    • Flubendiamide 480 SC (Contact + Ingestion Insecticide — Diamide, IRAC Group 28) @ 250 ml/ha
  • Chemical Control — Late Whorl Stage (35–40 days after emergence):
    • Emamectin Benzoate 5 SG (Semi-synthetic Insecticide — Avermectin, IRAC Group 6) @ 200 g/ha
    • Spinetoram 11.7 SC (Insecticide — Spinosyn, IRAC Group 5) @ 250 ml/ha
  • Direct all sprays into the whorl, not onto outer leaves.
  • Rotate between IRAC groups to delay resistance development.

2. Stem Borer

(Chilo partellus)

The Threat:

  • The stem borer larva bores into the central shoot of the young plant, causing the central leaf to die — the “deadheart” symptom that signals the loss of the main tiller.
  • At grain fill, continued borer activity destroys the ear, producing the “white ear” symptom of an empty, unfilled cob on an otherwise standing plant.
  • The borer weakens stalks and creates entry points for secondary fungal infections.
  • Population peaks typically occur 3–4 weeks after monsoon onset, making early-sown crops most vulnerable.
  • Losses of 10–15% are typical across central India.

The Solution:

  • Cultural Control:
    • Early planting as soon as monsoon rains establish helps the crop grow past the most vulnerable stage before peak borer populations develop.
    • Intercrop with cowpea or soybean to reduce infestation intensity.
    • Remove and destroy deadheart plants immediately to prevent population build-up within the field.
    • Use push-pull system — Desmodium (repels stem borer moths) and Napier grass on borders (trap crop).
  • Biological Control:
    • Release Trichogramma chilonis (Egg Parasitoid — Biological Control Agent) @ 1 lakh cards/ha in 6–7 releases starting 10 days after germination.
  • Chemical Control:
    • Apply Chlorantraniliprole 0.4 GR (Systemic Insecticide — Diamide, IRAC Group 28) or Carbofuran 3G granules (Systemic Insecticide — Carbamate, IRAC Group 1A) into the whorl @ 20–30 days after germination.
    • Carbofuran is a broad-spectrum carbamate; use only where other options have been exhausted and strictly follow PHI (pre-harvest interval).

3. Northern Corn Leaf Blight

(Exserohilum turcicum)

The Threat:

  • Northern corn leaf blight is a major fungal disease of maize in India, especially in humid regions like Karnataka, Andhra Pradesh, and the northeastern states.
  • Produces long, elliptical, cigar-shaped grey-green to tan lesions that begin on lower leaves after canopy closure and move upward.
  • Under high humidity and moderate temperatures (18–27°C), lesions expand rapidly, merge, and cause premature drying of leaves.
  • Early and severe defoliation before grain fill reduces cob size and seed weight.
  • Occurs in both kharif and rabi seasons where canopy humidity is high.
  • Yield losses up to 20% in susceptible hybrids.

The Solution:

  • Grow resistant hybrids — HQPM-1 and Bio-9637 are recommended by ICAR-IIMR, Hyderabad; update varieties each season as per advisory.
  • Maintain 75 cm row spacing to improve air circulation and reduce leaf wetness duration.
  • At first lesion appearance on lower leaves, apply:
    • Mancozeb 75 WP (Contact Fungicide — Dithiocarbamate, FRAC Group M3) @ 2.5 g/litre
    • Propiconazole 25 EC (Systemic Fungicide — Triazole, FRAC Group 3) @ 1 ml/litre
  • Repeat sprays at 10-day intervals if humid conditions persist.
  • Rotate between contact and systemic fungicides to prevent resistance development.

4. Drought at Silking Stage

The Threat:

  • Silking opens a pollination window of just five days — one of the most moisture-sensitive stages in the crop life cycle.
  • If soil moisture falls below field capacity at silk emergence, silks desiccate, pollen viability collapses, and pollination fails.
  • Results in empty, unfilled cobs despite otherwise healthy-looking plants.
  • Particularly severe in shallow, moisture-limited soils of Rajasthan and Karnataka’s dryland maize belt.
  • Causes 10–25% yield loss from a single weather event, with no scope for recovery later.

The Solution:

  • Grow drought-tolerant hybrids recommended by ICAR-IIMR — DHMH-1885 and DMRH-1301.
  • Provide one protective irrigation at silking if soil moisture falls below field capacity.
  • Use mulching with crop residue or dry weeds to conserve soil moisture and regulate soil temperature.
  • In rainfed conditions, adopt tied-ridge moisture conservation to maximise rainfall use.

5. Aflatoxin Contamination

(Aspergillus flavus)

The Threat:

  • Aflatoxin contamination is invisible, odourless, and among the most potent naturally occurring carcinogens.
  • The fungus Aspergillus flavus infects drought-stressed or insect-damaged cobs through silk channels or borer entry wounds.
  • Contamination increases when grain is harvested at high moisture or stored in warm, humid conditions.
  • Warm nights, high humidity, and drought are key drivers of contamination.
  • Contaminated grain is rejected at procurement centres, banned from export, and poses serious risks like liver damage and immune suppression in humans and livestock.

The Solution:

  • In the Field:
    • Broadcast Aflasafe (Biological Fungicide — Atoxigenic Aspergillus flavus Biocontrol Agent) @ 10 kg/ha at waist height (2–3 weeks before tasselling).
    • Aflasafe introduces non-toxin-producing strains that outcompete toxin-producing fungi.
    • Control stem borers and cob-feeding insects to prevent infection entry points.
  • At Harvest and Storage:
    • Harvest promptly at crop maturity.
    • Dry cobs to below 13% moisture before shelling.
    • Store grain in hermetic (airtight) bags (e.g., PICS bags) or metal silos to prevent fungal growth and toxin production.
Scroll to Top