Colletotrichum kahawae is a fungal plant pathogen that causes coffee berry disease (CBD) on Coffea arabica crops.

[1][2] This disease is considered to be one of the major factors hampering C.arabica production in the African continent, which represents the current geographic range of the fungus.

[4] Given the severity of the disease and the lack of effective control measures, there is great concern that the fungus may spread to other coffee producing continents, such as South America, which could have catastrophic consequences.

[6] The three former groups were later recognized as C. gloeosporioides Penz (CCM and CCA) and C. acutatum Simmonds (CCP), and proved to be non-pathogenic in green coffee berries.

[9] Several authors attempted to emend this anomaly but it was not until 1993 that Waller and Bridge described C. kahawae as the causal agent of CBD and as a distinct species based on morphological, cultural and biochemical characters[1] and more recently on multi-locus datasets.

[3][10] According to the American Phytopathological Society, C. kahawae is also a causal agent of the bacterial disease Brown Blight[11] Areca catechu (betelnut palm), Citrus reticulata (mandarin), Coffea arabica (arabica coffee), Coffea canephora (robusta coffee), Coffea liberica (Liberian coffee tree), Cyphomandra betacea (tree tomato), Eruca vesicaria (purple-vein rocket), Liquidambar styraciflua (Sweet gum), and Malus domestica (apple) are all hosts of C.

The common symptoms of the active lesions are dark brown, slightly sunken spots that begin small and eventually enlarges in area consuming the entire berry to become black.

Consequently, the pulp becomes brown, hard, and brittle while the surface of the berry remains smooth (except for the fungal fruiting structures).

Under humid conditions, the fruiting structures on the lesions may produce pink spore masses that become white with age.

[13] These lesions form stagnantly until the fruit begins to ripen creating a more beneficial environment for the fungus to grow.

Secondary inoculum may be produced by the pathogen as seen by concentric rings that are surrounded by emerging black acervuli within the lesion.

[4] The polycyclic disease cycle of Colletotrichum kahawae is heavily dependent on rain/water for conidial production, dispersion, germination and infection.

The fungus then feeds on the living tissue for a period of 48–72 hours post inoculation depending on the isolate aggressiveness.

[20] The first report of coffee berry disease caused Colletotrichum kahawae dates back to 1922 in western Kenya when it led to the destruction and abandon of C. arabica plantations in some regions.

[5] Until 2018, the disease remained constrained to the African continent, but reported occurrence now includes Colombia and Cuba in the Americas with Hainan island in Asia.

This process is made more difficult when a variety that has been bred for high resistance develops undesirable traits ( low yield, poor bean profile, etc.)

[28] It has also been noted that the use of the fungus Fusarium stilboides Wollenv and Epicoccum nigrum Link and some yeasts could function in limiting CBD progression.