Divisi
Teff rust
Uromyces eragrostidis · Fungal
Photo: James Kolmer · Public domain
Teff rust is a fungal disease of teff (caused by Uromyces eragrostidis). Wind-blown spores land on the leaves and, wherever dew or humid air keeps the leaf wet for hours, they germinate and infect, breaking out as rusty, powdery pustules that shed yet more spores. In cool, dewy weather the disease repeats cycle after cycle, working up the plant to the flag leaf and head, starving the grain as it fills. It survives between crops on volunteer teff, wild Eragrostis grasses and old crop residue.
Rasbak · CC BY-SA 3.0 
Howard F. Schwartz, Colorado State University, Bugwood.org · CC BY 3.0 us
Why it matters
Teff rust robs the leaves the plant needs to fill its tiny grain. In a bad, damp season it can take up to 40% of your harvest — nearly half — leaving shrivelled, light grain and lodged, tangled stalks that are hard to cut and thresh. It is hard to stop once it takes hold because every pustule you see is already firing off thousands of new spores on the wind, so the disease climbs from the lower leaves to the flag leaf and head faster than you can react. The only real wins come from getting ahead of it — before it reaches the top leaves that feed the grain.
When to act
Consider a fungicide when rust pustules become common on the upper leaves before or during heading, especially on a susceptible variety in cool, humid, dewy weather.
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 teff rust field guide
- Identify it
- Scout for it
- Control it
15 field-guide sections in the app
The full guide to teff rust — 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 teff rust?
The first thing you see: small rusty, powdery spots (pustules) scattered on the leaves and leaf sheaths, starting on the older lower leaves. Rub one with your finger and it leaves an orange, reddish-brown or brown dust on your skin — that dust is the spores. This rubbing-off dust is the surest sign it is rust and not something else.
When should I take action against teff rust?
Consider a fungicide when rust pustules become common on the upper leaves before or during heading, especially on a susceptible variety in cool, humid, dewy weather.
How do I control teff rust?
Prevent it first (your strongest tool): grow a rust-resistant or tolerant teff variety suited to your area — this is the single best defence, cutting the disease by around two-thirds with no spraying and no cost each season. If rust hits your fields most years, ask your extension officer or seed supplier which local variety stands up to it.
Which crops does teff rust affect?
Among the crops covered here: Teff.
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.
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