Coffee anthracnose is a group of fungal diseases caused by members of the Colletotrichum complex that produce dark, sunken lesions on cherries, plus leaf blight and twig dieback. Most of these fungi are opportunists that attack ripe, wounded or stressed tissue, but one aggressive member, Colletotrichum kahawae, is far more destructive and drives the separate disease known as coffee berry disease. This guide covers the broader anthracnose complex, how to recognise it, and how growers keep it in check.
What causes coffee anthracnose?
The term coffee anthracnose covers several closely related fungi rather than a single pathogen. The most commonly named culprit is Colletotrichum gloeosporioides (historically lumped with material called C. coffeanum, the "brown blight" fungus of East Africa), but modern DNA work has linked a whole cluster of species to anthracnose symptoms on coffee, including C. boninense, C. acutatum and C. gigasporum. These fungi are common, weakly aggressive residents of the coffee canopy that live on dead and dying tissue and turn parasitic mainly when the plant gives them an opening.
That opening usually means a ripe or over-ripe cherry, a sun-scorched leaf, a pruning cut, or wounds left by insects such as the coffee berry borer. On healthy green fruit these species largely stay latent, penetrating only the outer layers of the pericarp and waiting for ripening or stress to break the plant's resistance. That opportunistic behaviour is what separates ordinary anthracnose from its notorious relative, C. kahawae, which attacks unwounded green berries directly.
Symptoms of coffee anthracnose
Anthracnose shows up on almost every above-ground part of the plant, which is why it is easy to confuse with other disorders. Look for the following signs:
- Berries: dark brown to black, sunken lesions, sometimes with faint concentric rings, most often on ripening or over-ripe cherries. Spots enlarge, the pulp rots, and affected fruit frequently drops early or dries into a hard "mummy" on the branch.
- Leaves: small black to dark-brown spots with irregular margins, often with a pale grey centre ringed by a brown edge and a yellow (chlorotic) halo. Lesions can merge into large blighted patches, causing leaves to yellow and fall, typically the mid-branch leaves first.
- Twigs and branches: browning and dieback that usually begins at the shoot tip and works back along the stem, killing apical and lateral shoots.
- Blossoms: blackening and collapse of flowers (blossom blight), which reduces fruit set before cherries even form.
- Spore masses: in humid weather, pink to orange slimy pustules of spores (conidia) appear on the surface of lesions, a useful confirming sign.
Because the fungus favours ripe fruit, damage often peaks close to harvest, and infected beans can carry the fungus into storage, lowering cup quality. For context on the fruit these lesions attack, see our overview of the coffee cherry and its structure.
Anthracnose versus coffee berry disease
The single most important distinction for growers is between the everyday anthracnose complex and coffee berry disease (CBD). Both are caused by Colletotrichum, and CBD's pathogen even sits inside the C. gloeosporioides species complex, yet their impact could hardly be more different. We cover the destructive form in depth in our dedicated guide to coffee berry disease and C. kahawae; the table below summarises how the two compare.
| Feature | General anthracnose (e.g. C. gloeosporioides) | Coffee berry disease (C. kahawae) |
|---|---|---|
| Berry stage attacked | Mainly ripe, over-ripe, wounded or stressed berries | Green, expanding berries at any stage, wounded or not |
| Aggressiveness | Weak, largely opportunistic | Highly aggressive primary pathogen |
| Typical crop loss | Usually minor; worst near harvest and in storage | Frequently 50 to 80 percent of the crop in bad years |
| Colony in the lab | Fast-growing, off-white | Slow-growing, greyish-green |
| Distribution | Worldwide wherever coffee grows | Confined to Africa; first found in Kenya, 1922, and a major quarantine concern elsewhere |
The practical takeaway: sunken spots on your ripe cherries are almost always ordinary anthracnose, whereas rapidly blackening green berries at high altitude in Africa point to CBD, a quarantine-significant disease still absent from major producers such as Hawaii and much of Latin America.
Conditions that favour infection
Every member of the coffee-anthracnose complex is a warmth-and-moisture disease. Infection accelerates in wet, humid weather with temperatures around 24 to 28 °C (roughly 75 °F and up), while cool conditions below about 15 °C (59 °F) slow the fungus markedly and dry, low-humidity spells stall it almost completely. Prolonged leaf wetness from rain, fog or overhead irrigation lets spores germinate and infect, and dense, unpruned canopies trap humidity that keeps the leaf surface wet for longer.
Plant stress is the other half of the equation. Trees carrying a heavy crop, growing in poor or unbalanced soil, or weakened by other problems such as coffee leaf rust are far more prone to anthracnose because their tissues surrender their natural resistance. This is why anthracnose is often described as a "stress disease" that rides in behind other pests and disorders rather than a stand-alone threat.
How the fungus spreads and survives
The fungus overwinters, or in the tropics simply persists between crops, in mummified cherries, dead twigs, infected leaves and other debris on the tree and the ground. From these reservoirs it produces conidia that are splashed onto new tissue by rain and carried short distances on wind-driven mist, tools and workers' hands. On green fruit many infections stay latent, showing no symptoms until the cherry ripens and its chemistry shifts, at which point the disease flares. That hidden phase is a major reason sanitation matters: last season's overlooked mummies are this season's inoculum.
Regional patterns follow the weather. In the perennially humid lowlands of Southeast Asia and parts of the Americas, ripe-fruit anthracnose and twig dieback simmer year-round wherever canopies stay wet, and the disease is treated as a chronic quality problem rather than a yield emergency. In the cool, misty high-altitude arabica belts of East Africa, by contrast, the aggressive C. kahawae strain dominates the conversation, because those same conditions that merely irritate lowland farms let CBD explode. Understanding your local climate and elevation therefore tells you which Colletotrichum you are most likely fighting.
Diagnosis matters because anthracnose lesions can be mistaken for other troubles. Sunken, dark spots specifically on ripe cherries, accompanied by pink or orange spore slime in wet weather and tip-back dieback on twigs, point to anthracnose; uniform orange powder on the underside of leaves is rust, not anthracnose, and clean bore-holes with sawdust frays signal the berry borer instead. When symptoms are ambiguous, a lab culture that shows fast off-white growth (ordinary anthracnose) versus slow grey-green colonies (C. kahawae) settles the question.
Managing coffee anthracnose
Because the ordinary anthracnose fungi are opportunists, the most effective control is to deny them stressed tissue and stagnant, humid air. Management combines cultural, chemical and genetic tools within an integrated programme.
Cultural and sanitation practices
- Prune for airflow. Opening the canopy lets it dry faster after rain and cuts the humidity the fungus needs. Our guide to pruning coffee trees covers the timing and technique.
- Remove inoculum. Strip and destroy mummified cherries, dead twigs and heavily blighted leaves rather than leaving them to sporulate.
- Harvest cleanly and promptly. Over-ripe fruit left on the branch is the fungus's favourite target, so timely picking limits both infection and post-harvest carry-over.
- Balance nutrition. Well-fed trees resist opportunistic infection; correcting nitrogen, potassium and micronutrient shortfalls hardens tissue against attack.
Fungicides
Protective copper fungicides, copper hydroxide and copper oxychloride, are the workhorse chemistry because they are broad-spectrum, affordable and coat fruit and foliage before spores land. On high-value or high-pressure blocks, systemic products such as triazoles and strobilurins give curative and longer-lasting protection, but they must be rotated between chemical classes to avoid resistance. The key is to time sprays to wet, infection-favourable weather windows rather than a blanket calendar, and to concentrate coverage on developing and ripening fruit.
Resistant varieties
Where anthracnose or CBD pressure is chronic, planting resistant material is the most durable solution. CBD-resistant cultivars such as the Ruiru 11 and Batian lines bred in Kenya, and Catimor- and Sarchimor-derived varieties elsewhere, dramatically lower losses and reduce spray dependence. Choosing the right cultivar for local disease pressure is one of the highest-leverage decisions a grower makes; our broader overview of coffee diseases and pests puts anthracnose in context alongside rust, wilt and the borer.
The bottom line
For most farms, coffee anthracnose is a manageable, opportunistic disease of ripe and stressed tissue, a signal to tighten pruning, sanitation and nutrition rather than a crisis. The exception is coffee berry disease, whose C. kahawae pathogen turns the same fungal family into a green-berry killer capable of erasing most of a harvest. Knowing which lesion you are looking at, and matching your response to the risk, is the difference between a routine spray schedule and a season-defining loss.
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