Half the world eats rice daily. Blast and bacterial leaf blight are the two diseases that move fastest under the humid, dense canopies that irrigated rice creates.
- Grown in
- India, Bangladesh, Indonesia, Vietnam, China, Nigeria
- Season
- Wet season, 100–150 days
- Soil & pH
- Heavy clay that holds water, pH 5.5–6.5
What to scout for on Rice
- Diamond-shaped lesions with grey centres — rice blast
- Water-soaked stripes running down from leaf tips — bacterial leaf blight
- Rusty-brown speckling on older leaves — brown spot from potassium stress
- Empty panicles at harvest despite healthy foliage
Diseases that attack Rice
Leaf Spot
Septoria, Cercospora, Alternaria spp.
Bacterial Wilt
Ralstonia solanacearum / Erwinia tracheiphila
Nitrogen Deficiency
Abiotic — nutrient stress
Products you can buy for Rice
Typical registered products for the diseases above, with active ingredient, mixing rate, spray interval and pre-harvest interval. Rotate FRAC/IRAC groups to avoid resistance.
Chlorothalonil 75% WP
Active ingredient: Chlorothalonil
- Dose:
- 2 g per litre (1.5–2 kg/ha)
- Interval:
- Every 7–10 days
- PHI:
- 7 days
Backbone protectant for Septoria and Cercospora leaf spots. Full leaf coverage, including undersides, is essential.
Mancozeb 80% WP
Active ingredient: Mancozeb
- Dose:
- 2.5 g per litre
- Interval:
- Every 7 days
- PHI:
- 7 days
Adds zinc and manganese nutrition alongside disease control.
Azoxystrobin 23% SC
Active ingredient: Azoxystrobin
- Dose:
- 1 ml per litre (500 ml/ha)
- Interval:
- Every 14 days, maximum 2 per season
- PHI:
- 3–7 days
Strong translaminar movement. Always tank-mix or alternate with a multi-site to protect the QoI group.
Copper hydroxide 77% WP
Active ingredient: Copper hydroxide
- Dose:
- 2 g per litre
- Interval:
- Every 10 days
- PHI:
- 1–3 days
Use when bacterial leaf spot cannot be ruled out — copper covers both bacterial and fungal spotting.
Urea 46-0-0
Active ingredient: Urea nitrogen 46%
- Dose:
- 100–150 kg/ha split, or 5 g per litre as a 2% foliar spray
- Interval:
- Split into 2–3 side-dressings across the growth cycle
- PHI:
- Not applicable
Incorporate into moist soil within a day — surface urea can lose 30% of its nitrogen to volatilisation.
NPK 15-15-15 compound
Active ingredient: Balanced N-P-K
- Dose:
- 200–300 kg/ha at planting
- Interval:
- Basal dose at planting or transplanting
- PHI:
- Not applicable
The correct starting point when no soil test exists; follow up with nitrogen-only top-dressing.
Doses shown are typical registered field rates. Always read the product label, confirm the product is registered for your crop and country, respect the pre-harvest interval (PHI), and wear the protective equipment the label specifies. PlantWatch AI provides agronomic guidance, not a legal spray recommendation.
Is your Rice showing symptoms right now?
Photograph the leaf and PlantWatch AI will diagnose the disorder and prescribe the exact product, dose and spray interval to use next.
Diagnose a plant