Divisi
Sorghum grain mould
· Fungal
Photo: division, CSIRO · CC BY 3.0
Grain mould is a team of fungi — mainly Fusarium, Curvularia, Alternaria and Phoma — that settle on the developing grain of sorghum and pearl millet when the head flowers and fills during warm, wet, humid weather (about 20-30 degrees C with the air staying damp, above 85% humidity). They rot and discolour the grain while it is still forming, so the harvest is light, chalky and low-value. Worse, some of these fungi make invisible poisons called mycotoxins that can make the grain unsafe to eat or to feed to animals. The same fungi, signs, timing and controls apply to both crops; the only difference is the shape of the head you are checking.
Why it matters
Grain mould attacks the part you actually harvest — the grain itself — so in a bad wet year it can spoil up to half of your crop (50%) on sorghum or pearl millet. Once the fungus is inside the forming grain there is no spray that can un-rot it; the damage is done and locked in. On top of the lost weight and the low price mouldy grain fetches, some of these moulds leave behind mycotoxins — invisible poisons — that can make the grain dangerous to eat or to feed to your animals. That is why this one is about preventing it before the wet weather hits, not curing it after.
When to act
Rain forecast or persistent humidity during grain filling on a susceptible, open-panicle variety; discoloured grain appearing on developing heads.
This guidance is general, compiled from published agronomic references including FAO and CABI. Thresholds and timing shift with your crop, your variety and the season.
In much of the region a spray is simply called mushonga — medicine. But a chemical group you cannot name is one you cannot rotate, and a product you did not write down has no pre-harvest interval you can observe. Mushonga, and other farming words →
The full sorghum grain mould field guide
- Identify it
- Scout for it
- Control it
14 field-guide sections in the app
The full guide to sorghum grain mould — every symptom to check, how and when to walk your field looking for it, and the controls that actually work, ranked. Built into your crop plan, so you are told to look before it costs you a harvest.
Crops it affects
Frequently asked questions
How do I identify sorghum grain mould?
The damage (first and clearest sign): instead of the true clean colour of your variety, the grains on the head turn pink, orange, grey, white or black, and the head looks dirty and blotchy. Look closely and you'll see a fuzzy or felty fungus growth sitting right on the kernels, like fine cotton or velvet. This is the same on sorghum and pearl millet — only the head shape differs (sorghum carries an open branching head, pearl millet a dense finger-like candle).
When should I take action against sorghum grain mould?
Rain forecast or persistent humidity during grain filling on a susceptible, open-panicle variety; discoloured grain appearing on developing heads.
How do I control sorghum grain mould?
Prevent first — choose the right variety (your strongest tool): grow varieties bred to resist mould — ones with tight glumes that seal the grain, and coloured or tannin-containing grain (tannin is a natural bitter compound the fungus struggles with). This holds for both sorghum and pearl millet. Where the market lets you, avoid the loose, open, pure-white food types in wet areas. A resistant variety is the single most effective thing you can do.
Which crops does sorghum grain mould affect?
Among the crops covered here: Pearl millet, Sorghum.
Catch it before it costs you a harvest
Divisi builds scouting into your crop plan — it tells you when to walk your field, what to look for at that stage, and what to do when you find it. Free for farmers, works offline.
Check what grows on your farm