What is Coffee Berry Disease?

Coffee Berry Disease (CBD) is a fungal infection caused by Colletotrichum kahawae that attacks developing coffee cherries, turning them black and causing them to drop before ripening. In a bad outbreak it can devastate a harvest - turning what should have been a quality crop into unmarketable defective material.

It's most prevalent in East Africa - Kenya, Ethiopia, Uganda - where humid conditions favour the spread of fungal spores through rain splash and wind. The damage is direct and total: infected cherries never mature, reducing yield and producing no usable beans.

Breeding for CBD resistance has been a central focus of East African coffee research for decades. Kenya's Ruiru 11 was developed specifically in response to it. Management also involves copper-based fungicide applications and careful timing during the critical flowering-to-cherry development window.