Spray Schedule for Paddy (Rice): From Nursery to Harvest
A practical week-by-week spray schedule for paddy grown in Tamil Nadu — covering both Kuruvai and Samba seasons. Includes key pest stages, economic thresholds, and PHI checkpoints.
By Yesell Crops Care Team
Paddy is the most widely grown crop in Tamil Nadu, across the Cauvery delta (Thanjavur, Tiruvarur, Nagapattinam) and upland areas. Disease and pest management is critical — a single unchecked BPH outbreak or neck blast infection can wipe out 30–70% of yield.
This schedule is a general guide. Always verify with the product label and consult your local agricultural extension officer for district-specific advice.
Two Main Seasons in Tamil Nadu
- Kuruvai: June/July sowing — harvest October/November (short-duration varieties, 100–115 days)
- Samba: August/September sowing — harvest January/February (medium/long-duration, 130–160 days)
Pest and disease pressure differs between seasons. Samba paddy carries higher blast and BPH risk due to cooler, longer growing conditions.
Nursery Stage (Days 1–25)
| Days After Sowing | Watch For | Action |
|---|---|---|
| 1–7 | Seed germination; damping off | Use seed treatment before sowing; ensure nursery drainage |
| 8–14 | Leaf blast, root rot | If blast lesions appear, apply recommended fungicide |
| 15–25 | Blue-green algae, thrips | Scout daily; treat thrips if infestation is heavy |
Transplanting to Active Tillering (Days 25–45 after transplanting)
| Growth Stage | Primary Threats | Threshold / Trigger |
|---|---|---|
| 7–14 DAT | Yellow stem borer, case worm | "Dead heart" symptoms or 5% damaged tillers |
| 14–21 DAT | Leaf folder, Brown Plant Hopper | 1 leaf folder/tiller; 5 BPH/tiller at base |
| 21–35 DAT | Sheath blight, BPH | Disease lesions at 5th sheath; BPH colonies forming |
| 35–45 DAT | Gall midge, whorl maggot | Silver shoot (gall midge) or 10% "dead heart" |
BPH warning: Do NOT use synthetic pyrethroids (lambda-cyhalothrin, cypermethrin, fenvalerate) for BPH in paddy. These kill natural enemies (spiders, mirid bugs) and cause BPH resurgence — making outbreaks far worse. Use BPMC, imidacloprid, or thiamethoxam as per registration.
Panicle Initiation to Heading (Days 45–75 after transplanting)
This is the highest-risk period. Disease during heading causes white panicles and complete yield loss.
| Growth Stage | Primary Threats | Key Action |
|---|---|---|
| Panicle initiation (PI) | Neck blast, sheath rot | Protective fungicide spray at PI — do not wait for symptoms |
| Boot leaf stage | Neck blast | Second fungicide spray 7–10 days after PI spray |
| 50% heading | False smut, brown spot | Monitor; treat if false smut balls appear |
Grain Filling to Maturity (Days 75–110)
| Growth Stage | Watch For | Note |
|---|---|---|
| Milky stage | Rice bug, hispa | Treat rice bug if 1+ per hill; avoid late sprays |
| Dough stage | Grain discolouration | Usually secondary infection; improve field drainage |
| Pre-harvest (final 21 days) | PHI compliance | Check your last spray date — respect PHI strictly |
PHI Checkpoint Before Harvest
This is the most important compliance step. Before you apply any product in the final 3–4 weeks of the crop:
- Look up the PHI for that product on that crop (printed on the label)
- Calculate your expected harvest date
- Confirm: harvest date minus last spray date ≥ PHI
- If the maths doesn't work, choose a product with a shorter PHI — or do not spray
Spray Timing for Maximum Efficacy in Paddy
- Best time: Early morning (6–9 AM) — leaves are wet with dew, pests are active on the plant, and temperature is cool
- Use enough water volume: minimum 400 litres/acre for knapsack sprayer
- Direct nozzle at the base of the plant for BPH and stem borer; direct at the canopy for leaf folder, blast, and BPH on leaves
- Never spray during strong winds or when rain is forecast within 2 hours
Need help planning your spray programme? Contact us at support@yesellcropscare.com.