Shoot fly
Its maggot cuts the central shoot of young cereal seedlings, causing dead heart in the first weeks — a seedling-stage pest you beat with timely sowing.
- Pest type
- Fly (maggot in shoot)
- Attacks
- Seedling central shoot
- Worst in
- Late-sown / slow seedlings
- Main risk
- Seedling dead heart
Overview
Shoot fly is a small grey fly, a little like a housefly, that attacks sorghum, pearl millet and maize seedlings in the first two to four weeks after emergence. The female lays a single white cigar-shaped egg on the underside of a young leaf; the hatching maggot crawls down and cuts the growing central shoot.
The result is "dead heart" — the central shoot withers to a dry, straw-coloured stub that pulls out easily while the outer leaves stay green, exactly like stem borer but far earlier, at the seedling stage. Slow-growing, late-sown and thin crops suffer most because the vulnerable seedling window is longer. Once the crop is past about four weeks and growing fast, shoot fly is no longer a threat, so the whole battle is protecting the seedling.
How to identify it
- Dead heart in seedlings (first 1–4 weeks) — the central shoot dries to straw colour and pulls out easily while outer leaves stay green.
- A single small, white, cigar-shaped egg laid flat on the underside of a young leaf.
- Small grey flies resting on the crop in the early morning at the seedling stage.
- Damage worse in late-sown fields and thin, uneven stands.
The damage it does
- Dead heart that kills the main shoot of seedlings; the plant may put out weak side tillers that mature late and unevenly.
- Severe stand loss in late-sown or slow-growing crops, sometimes needing a gap-fill or resowing.
- Uneven maturity and reduced yield from the tillering triggered by early shoot loss.
- Little threat once the crop is past the vulnerable seedling window and growing vigorously.
When to act
- The decisions that matter are made at sowing — timing, seed rate and seed treatment — because the pest only attacks the seedling.
- Scout for eggs and dead hearts in the first few weeks; a rising dead-heart count signals pressure.
- Past about four weeks of vigorous growth, no further action is needed.
Organic & cultural control
- Sow early and at the recommended time so seedlings pass the vulnerable stage before shoot-fly numbers peak — the single most effective step.
- Use a higher seed rate and thin later, so enough plants survive even if some are hit, and grow resistant/tolerant varieties where available.
- Remove and destroy dead-heart seedlings, and keep the field and bunds free of alternate grassy hosts.
- A vigorous, well-fertilised, well-watered seedling outgrows the risk faster.
Chemical control
- A registered insecticidal seed treatment is the standard, most economical protection through the seedling window on shoot-fly-prone sowings.
- CIB&RC-registered seed treatments/early sprays (as registered for the crop, e.g. imidacloprid/thiamethoxam seed treatment) protect the establishing seedling; apply per the label.
- An early foliar spray at the seedling stage can supplement seed treatment where egg-laying is heavy.
- Confirm the current recommendation and dose for your crop and zone with your local KVK.
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 sorghum/millet seedlings are dying with a dry central shoot. Is it shoot fly or stem borer?
Both cause dead heart, but timing tells them apart: shoot fly hits very young seedlings in the first 1–4 weeks, while stem borer usually comes a bit later and continues into the stem. If your dead hearts are appearing in the first few weeks after emergence, it is almost certainly shoot fly. Look for a single white cigar-shaped egg on the leaf underside.
Why is early sowing recommended against shoot fly?
Because shoot fly only attacks the seedling stage. If you sow early (or at the recommended time) the crop passes the vulnerable first few weeks before shoot-fly populations peak, so far fewer seedlings are hit. Late-sown, slow-growing crops sit in the danger window longer and suffer most.
What is the most reliable protection?
A registered insecticidal seed treatment combined with timely sowing and a slightly higher seed rate. The seed treatment protects the seedling through the vulnerable window, timely sowing shortens that window, and the extra seed rate ensures enough plants survive. Remove dead-heart seedlings and confirm the current seed-treatment recommendation with your KVK.
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.