Sorghum midge
A tiny orange fly that destroys sorghum grain from inside the flowering floret — worst on late and staggered crops, beaten by sowing together.
- Pest type
- Fly (maggot in floret)
- Attacks
- Flowering florets / grain
- Worst in
- Flowering; late/staggered crops
- Main risk
- Blank, unfilled earheads
Overview
The sorghum midge is one of the most damaging pests of sorghum (jowar) grain, and it strikes at a single, narrow window — flowering. The tiny, delicate orange fly lays an egg inside a flowering spikelet; the maggot feeds on the ovary and the developing grain, so that floret produces no seed.
The result is an earhead dotted with blank, unfilled spikelets and, in a heavy attack, a largely chaffy head — often with tiny papery pupal cases left at the tips of the empty florets. Because the midge can only attack florets that are actually in flower, a crop that flowers when few midges are around escapes, while late and staggered-sown crops that flower over a long period are hammered. That makes synchronised, timely, community-wide sowing the single most powerful control.
How to identify it
- Tiny, delicate orange-red flies on the earheads during flowering, most visible in the morning.
- Blank, unfilled spikelets scattered through the earhead; a heavy attack leaves a largely chaffy head.
- Tiny white/papery pupal cases at the tips of the empty florets, a giveaway after the maggots have fed.
- Damage that only ever appears on heads that flowered during a midge peak — often the late-flowering ones.
The damage it does
- Destroyed grain in attacked florets, giving blank, unfilled spikelets and reduced grain per head.
- Largely chaffy earheads in a heavy infestation — a major direct yield loss.
- Disproportionate loss on late and staggered-sown crops that flower over a long window.
- Loss that is set at flowering and cannot be recovered afterwards.
When to act
- The decisive action is at sowing — sow early, on time and in synchrony with neighbours so the crop flowers before or together, away from the midge peak.
- Monitor the flies on the earheads at flowering; this is the only window when a spray can protect the florets.
- Since damage is fixed at flowering, there is nothing to gain from acting after the earhead is set.
Organic & cultural control
- Sow early, on time and community-wide in synchrony, so flowering is uniform and brief and escapes the midge build-up — the most powerful control.
- Grow recommended midge-resistant/tolerant sorghum varieties where available.
- Avoid late and staggered sowing, and destroy volunteer and off-season sorghum that carries the midge over.
- Conserve natural enemies (parasitoids of the midge) by avoiding unnecessary sprays.
Chemical control
- If protection is needed, an insecticide has to be applied during flowering, when the adult flies are on the earheads — the only time it can protect the florets.
- Use a CIB&RC-registered insecticide for sorghum earhead pests, timed to flowering and, ideally, to morning fly activity.
- Because the window is so narrow and damage is fixed at flowering, cultural control (synchronised sowing, resistant varieties) carries most of the load; observe the pre-harvest interval.
- Confirm the current recommendation and dose for your area 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 earheads have lots of blank, unfilled grains. What causes it?
That pattern of blank, unfilled spikelets scattered through the earhead is classic sorghum midge damage. A tiny orange fly lays inside the flowering floret and its maggot destroys the developing grain, leaving the spikelet empty — often with a tiny papery pupal case at the tip. Look for the small orange flies on the heads at flowering to confirm.
Why does synchronised sowing control sorghum midge?
Because the midge can only attack florets that are actually flowering. If the whole area flowers together and briefly, the crop passes through the vulnerable window fast and before midge numbers peak. Late and staggered crops flower over a long period, giving the midge continuous florets to attack — which is why sowing early, on time and in synchrony is the main defence.
Is spraying useful against sorghum midge?
Only if timed precisely to flowering, when the adult flies are on the earheads — that is the sole window when a spray can protect the florets. Once flowering is past, the damage is fixed and spraying does nothing. Because the window is so narrow, synchronised sowing and resistant varieties do most of the work, with a flowering-time spray as a supplement.
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.