Dr. Phyto
coffee leaf rust
Hemileia vastatrix
Symptoms
Bright orange-yellow powdery pustules on undersides of leaves (very diagnostic), yellow halos on upper leaf surfaces above pustules, severe infection causes premature leaf drop, branch dieback + reduced bean yield, plants completely defoliated in epidemic years lose 30-70% of crop.
Plants affected
Easily confused with
- anthracnose
How to tell them apart: On Coffea arabica, Hemileia vastatrix (coffee leaf rust) and Colletotrichum gloeosporioides (anthracnose) both start as pale chlorotic yellow spots on the upper leaf surface, but they diverge fast. Turn the leaf over: rust produces bright orange-to-yellow powdery spore masses on the LOWER surface (the single decisive sign), forming round to oval yellow-orange lesions that later develop necrotic brown centres. Anthracnose instead forms sunken dark-brown to tan necrotic patches, usually starting at leaf margins or tips, often with concentric zoning, a yellow halo, and tiny black fruiting dots (acervuli) on the UPPER surface, and never bears orange powder underneath. Rust spreads in warm humid plantations; anthracnose lesions worsen on stressed or wounded tissue and spread to twigs and berries.
Treatment
Dr. Phyto builds a dated, step-by-step treatment plan with country-approved products — start a free diagnosis to get yours.
Common questions
- How do I recognise coffee leaf rust on Arabica coffee?
- Bright orange-yellow powdery pustules on undersides of leaves (very diagnostic), yellow halos on upper leaf surfaces above pustules, severe infection causes premature leaf drop, branch dieback + reduced bean yield, plants completely defoliated in epidemic years lose 30-70% of crop.
- Do I have to report coffee leaf rust?
- No. coffee leaf rust is not a notifiable organism, so there is nothing to report to an authority. Treat it as a normal garden problem.
- How is coffee leaf rust treated?
- Mainly with biological and cultural measures — removing affected material, changing the conditions that favour it, and treating with agents approved in your country. The exact steps and their timing depend on the plant, the season and where you live: Dr. Phyto works them out in a free diagnosis.
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