Weed control schedules in major field crops

Principles of Weed Control Scheduling

• Critical Period of Weed Control (CPWC): Time during which weeds must be controlled to prevent yield loss.
• Pre-emergence vs. Post-emergence: Timing of herbicide or mechanical control before or after crop emergence.
• Frequency: Multiple interventions may be necessary depending on weed pressure, crop growth, and season.

Weed Control Schedules in Field Crops

1. Rice

• Critical Period of Weed Competition (CPWC): First 40 days after transplanting or direct seeding.
• Schedule:
  • 0–3 Days After Transplanting (DAT): Apply pre-emergence herbicide (Butachlor, Pretilachlor, Oxadiazon).
  • 20–25 DAT: First hand weeding or use post-emergence herbicide (Bispyribac-sodium, Fenoxaprop, or 2,4-D for broadleaf weeds).
  • 40–45 DAT: Second weeding (manual or mechanical).
• Note: In direct-seeded rice, weeds emerge earlier; hence pre-emergence control is crucial.

2. Wheat

• CPWC: 20–50 Days After Sowing (DAS).
• Schedule:
  • 0–3 DAS: Pre-emergence Pendimethalin.
  • 25–30 DAS: Post-emergence herbicides (Clodinafop, Sulfosulfuron, Metsulfuron) depending on weed type (Phalaris minor, Avena fatua, broadleaves).
  • Mechanical Weeding: Inter-row hoeing if sown in wide rows.

3. Maize

• CPWC: 15–45 DAS.
• Schedule:
  • At Sowing: Atrazine or Metolachlor (pre-emergence).
  • 20–25 DAS: Hand weeding / Inter-row cultivation.
  • 25–30 DAS: Post-emergence Nicosulfuron for grassy weeds.

4. Pulses (Chickpea, Pigeon pea, Lentil, etc.)

• CPWC: First 30–40 DAS.
• Schedule:
  • 0–3 DAS: Pendimethalin (pre-emergence).
  • 20–25 DAS: First hand weeding / hoeing.
  • 30–40 DAS: Second weeding if necessary.
  • Selective post-emergence (Imazethapyr for chickpea, soybean, lentil).

5. Oilseeds

Groundnut

• CPWC: 20–45 DAS.
• Schedule:
  • At Sowing: Pendimethalin or Fluchloralin.
  • 20–25 DAS: Hand weeding + hoeing.
  • 30–35 DAS: Quizalofop or Imazethapyr for post-emergence control.

Soybean

• CPWC: 15–45 DAS.
• Schedule:
  • 0–3 DAS: Flumioxazin / Pendimethalin (pre-emergence).
  • 20–25 DAS: Imazethapyr or Acifluorfen (post-emergence).
  • Hand weeding: 25–30 DAS if needed.

6. Cotton

• CPWC: 20–60 DAS.
• Schedule:
  • Pre-sowing: Glyphosate for perennial weeds in fallow fields.
  • 0–3 DAS: Pre-emergence Pendimethalin.
  • 20–25 DAS: Hand weeding + intercultural.
  • 30–40 DAS: Post-emergence Propaquizafop for grasses.
  • Later stage: Mulching or intercropping (e.g., cowpea) for weed suppression.

7. Sugarcane

• CPWC: First 90 Days After Planting (DAP).
• Schedule:
  • Pre-planting: Eliminate perennial weeds with glyphosate.
  • 0–5 DAP: Pre-emergence Atrazine, Pendimethalin.
  • 30–45 DAP: First hoeing + earthing up.
  • 60–75 DAP: Second intercultural and earthing up.
  • Later: Ratoon crops require strong management with both pre- and post-emergence herbicides.

General Weed Control Calendar