Bakanae disease (rice)
Nursery seedlings grow unnaturally tall, thin and pale yellow-green ("foolish seedling") and mostly die before or soon after transplanting — a seed-borne fungus.
- Pathogen
- Fusarium fujikuroi (fungus)
- Spreads by
- Infected seed; soil & stubble
- Favoured by
- Warm, humid nursery; untreated seed
- Main risk
- Seedlings die; thin, low-yield stand
Overview
Bakanae, also called "foolish seedling disease," is a fungal disease of rice caused by Fusarium fujikuroi, carried mainly inside and on the seed. The fungus makes a gibberellin-like hormone that pushes infected seedlings to grow abnormally tall, thin and pale yellowish-green — clearly taller than healthy seedlings in the same nursery bed. Most of these overgrown seedlings die before or soon after transplanting; the few that survive are spindly, put out few tillers, and some infected plants stay stunted instead of overgrown.
Warm, humid nursery conditions favour the disease, and using seed saved year after year from a field that had bakanae lets the infection build up. Because the fungus travels mainly on and inside the seed, management is centred on clean, certified, treated seed and roguing out abnormal seedlings early — there is no cure once a plant is infected.
How to identify it
- Infected seedlings grow unusually tall, thin and pale yellowish-green — clearly taller than healthy seedlings in the same nursery bed.
- Most overgrown seedlings die before or soon after transplanting; survivors are spindly with few tillers.
- Some infected plants stay stunted instead of overgrown, or show white/pink fungal growth at the base in humid weather.
- On surviving infected tillers at a later stage, panicles may be empty or only partly filled, and stems can show extra roots at the nodes.
What causes it and when
- Caused by the fungus Fusarium fujikuroi, carried mainly inside and on the seed.
- The fungus makes a gibberellin-like hormone that causes the abnormal elongation seen in infected seedlings.
- Warm, humid nursery conditions favour the disease; seed saved repeatedly from an infected field builds up infection over seasons.
- The fungus also survives in infected stubble and soil, though seed is the main carrier into a new crop.
Cultural & organic control
- Use certified, disease-free seed from a healthy crop; never save seed from a field that showed bakanae symptoms.
- Rogue out (uproot and destroy) tall, thin, overgrown seedlings in the nursery before transplanting so infection does not carry into the main field.
- Hot-water seed treatment — soak seed in water at about 52-54°C for 10-15 minutes — kills much of the seed-borne fungus before sowing.
- Keep the nursery bed clean of stubble from a previous infected crop and avoid transplanting any seedling that looks abnormal.
Chemical / seed treatment
- Treat seed before sowing with a recommended fungicide (such as a carbendazim-based product) as per the label, or with a Trichoderma-based bio-seed treatment.
- Seed treatment is the single most effective step, since the fungus travels mainly on and inside the seed.
- There is no effective spray cure once plants are infected in the field — the focus is clean seed, not a curative spray.
- Confirm the current recommended fungicide, dose and availability with your local KVK, as recommendations are updated from time to time.
Prevent it coming back
- Always start with certified seed and treat it before sowing, every season.
- Rogue out abnormal seedlings early and never let an infected crop go to seed.
- Use a fresh nursery bed where possible and avoid leftover stubble from an infected crop.
Crops most at risk
Where this problem is called out in our crop guides — open a crop for the full package of practices.
Varieties to consider
Named seed varieties whose resistance or susceptibility to this problem is documented on their own variety page.
Frequently asked questions
My rice nursery has some seedlings much taller and paler than the rest — what is it?
This is likely bakanae ("foolish seedling") disease, a seed-borne fungus (Fusarium fujikuroi) that makes infected seedlings shoot up abnormally tall, thin and pale yellow-green. Most of these overgrown seedlings die before or soon after transplanting. Uproot and destroy them rather than transplanting — don't let them go into the main field. The real fix for next season is certified, treated seed, since the fungus travels mainly on the seed.
How do I stop bakanae from coming back every year?
Start with certified, disease-free seed every season and treat it before sowing — either hot-water treatment (52-54°C for 10-15 minutes) or a recommended fungicide/Trichoderma seed treatment. Never save seed from a field that had bakanae symptoms, and rogue out any abnormal tall seedlings in the nursery before transplanting. These steps together, repeated every season, keep the fungus from building up.
Is there any spray to cure bakanae once plants are already infected?
No — once a seedling is infected, there is no spray that cures it. Uproot and destroy abnormal seedlings so they don't carry the fungus into the main field or into next season's seed. All the effective control happens before infection: certified seed, seed treatment, and a clean nursery bed.
Symptoms and control measures follow ICAR, KVK and state agricultural-university package-of-practices; any named chemical is a registered use. Always read the product label and confirm the dose for your crop and zone. editorial policy.