Finger millet blast
Spindle leaf spots, a black rot on the neck below the ear, and shrivelled fingers — a fungus driven by humid, cloudy weather at flowering and by excess nitrogen.
- Pathogen
- Fungus (Pyricularia grisea)
- Spreads by
- Air-borne spores; seed, stubble & grasses
- Favoured by
- Humid cloudy weather at flowering, excess N
- Main risk
- Choked grain fill; empty ears
Overview
Blast, caused by the fungus Pyricularia grisea, is the most important disease of finger millet (ragi). It appears in three phases. Leaf blast makes spindle- or diamond-shaped spots with a grey centre and a brown border, which merge and dry the leaf. Neck blast is a black, shrivelled, often broken zone on the stalk just below the ear head. Finger blast darkens and shrivels the fingers themselves so they fill poorly or not at all.
Neck and finger blast are the phases that cost yield, because they cut off grain filling directly and can empty the ear. The disease is favoured by long humid, overcast, drizzly weather at flowering, a dense over-fertilised canopy, and heavy nitrogen. It is seed-borne and also carries over on infected stubble and on grasses. Management combines a resistant variety, treated seed, moderate nitrogen and a fungicide timed to the boot-to-ear stage when blast weather sets in.
How to identify it
- Leaf blast: spindle- or diamond-shaped spots, grey centre with a brown border, merging so the leaf dries.
- Neck blast: a black, shrivelled, weak zone on the stalk just below the ear head — the ear may snap or hang.
- Finger blast: dark, shrivelled fingers with poorly filled or empty grain.
- Worst after a spell of humid, cloudy, drizzly weather at flowering, and in a lush, heavily fertilised crop.
What causes it and when
- The fungus Pyricularia grisea, spread by air-borne spores and carried over on infected seed, stubble and grasses.
- Favoured by long leaf-wetness and dew, overcast humid weather at the flowering and grain-set stage, a dense canopy and heavy nitrogen.
- Leaf blast can show from tillering; neck and finger blast strike from ear emergence through grain fill.
Cultural & organic control
- Grow a blast-resistant variety — the most reliable defence (GPU 28 and GPU 67 in Karnataka, GPU 45 for late sowing).
- Treat seed with carbendazim or a Trichoderma formulation against seed-borne blast before sowing the nursery or drilling.
- Keep nitrogen moderate and split; avoid a heavy single dose that makes the crop lush.
- Use recommended spacing so the canopy is open and airy, keep the field drained, and destroy infected stubble and volunteer grasses after harvest.
Chemical control
- Spray a recommended fungicide (tricyclazole, or a carbendazim/mancozeb combination) at the boot-leaf to ear-emergence stage when humid, cloudy blast weather sets in.
- Repeat once at flowering if the weather stays wet, to protect the neck and fingers.
- A protective spray timed to the weather is far cheaper than the yield lost waiting for black necks to appear.
- Confirm the current product, dose and timing for your area with your KVK.
Prevent it coming back
- Base the crop on a resistant variety, treated seed and moderate, split nitrogen.
- Plan the boot-to-ear protective spray in advance where blast is regular, rather than reacting after the necks rot.
- Rotate finger millet with a non-host crop on a badly hit field, and clear infected stubble and field-edge grasses.
Crops most at risk
Where this problem is called out in our crop guides — open a crop for the full package of practices.
Frequently asked questions
My ragi has black, shrivelled stalks just below the ear. What is it?
That is neck blast, the most damaging phase of finger millet blast. A black rot girdles the stalk just below the ear head, so grain filling is choked off and the ear may hang or snap. There is no cure for an affected ear — protect the rest of the crop with a recommended fungicide at ear emergence and flowering, and grow a resistant variety such as GPU 28 or GPU 67 next season.
How do I prevent blast in finger millet?
Grow a blast-resistant variety, treat the seed with a fungicide before sowing, keep nitrogen moderate and split rather than heavy, use recommended spacing so the canopy stays open, and keep the field drained. Where humid, cloudy weather sets in around flowering, spray a recommended fungicide (tricyclazole) at the boot-to-ear stage before symptoms appear.
Is finger millet blast the same as rice blast?
They are caused by very closely related fungi in the Pyricularia / Magnaporthe group, and the leaf symptoms look similar, but they are treated as separate diseases on separate hosts. The management principles — resistant variety, treated seed, moderate nitrogen, timed protective fungicide — are the same.
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.