Phoma Leaf Spot
Fungal disease
Overview
Phoma leaf spot (sometimes called Phoma blight) is caused by fungi of the Phoma group. It mostly attacks young, soft tissue: new leaves, shoot tips and sometimes flower buds and young berries. It is more often reported in cooler, higher-altitude coffee areas and after periods of cold rain, strong wind or hail that damage the leaves.
How to tell it apart
- No orange powder on the underside, unlike coffee leaf rust.
- Mainly affects the newest growth rather than older leaves.
- Leaf tips burnt by wind, drought or fertiliser can look similar. An expert can tell these apart.
Common visible symptoms
- Dark brown to black patches on young leaves, often starting at the tip or the edge.
- Affected young leaves may curl, become misshapen or dry out.
- Shoot tips can turn black and die back.
- Damage often appears after cold, wet or windy weather.
Management options
- Have the problem confirmed by an extension worker; Phoma is easily confused with weather damage.
- Prune out dead shoot tips so the tree can grow new healthy shoots.
- Fungicide use should only follow advice from an extension worker and the product label. CAWA SCAN does not give product names or rates.
Prevention practices
- Plant windbreaks or keep moderate shade to reduce wind and cold damage to young growth.
- Avoid wounding young shoots during field work.
- Keep trees well nourished so they produce strong new growth.