There are 40 species in the genus Coffea (family Rubiaceae) that are susceptible to the disease caused by M. coffeicola, but only a few that are commercially relevant.
[2] Coffea arabica ranges in growth habit from a shrub to a small tree and has ovate, shiny, pointed leaves, with clustered white flowers.
[1] On leaves, lesions begin as chlorotic (yellow) spots that expand to become deep brown and necrotic on the upper leaf surface.
In general, lesions of this species are able to fuse, and can form large irregular areas of necrotic tissue.
[4] On green berries, this includes irregularly shaped brown, sunken lesions that are surrounded by a purple halo.
At this stage, fruit is susceptible to attack by opportunistic bacteria and fungi (such as Colletotrichum gloeosporioides), though symptoms from these organisms should not be falsely attributed to M. coffeicola.
M. coffeicola is a tropically adapted pathogen due to its host narrow geographical range around the equator.
[6] The continuous production of conidia guarantees infection at multiple stages of plant development (in leaves, flowers, and fruit).
To manage humidity a farmer can prune to allow for air circulation and ensure the soil has proper drainage.
[1] In order to maintain proper plant nutrition, soil testing and a fertilization regiment are essential for combating this pathogen.
Plant symptoms such as chlorosis, leaf curling, and bronzing along the edges of leaves can be used to diagnose specific nutrient deficiencies.
Also to minimize competition between adjacent crops, it is important to properly space coffee plants in 8 ft. by 8 ft. areas.
In Hawaii, farmers often spray tri-annually, using 1.5–6 lbs of fungicide per 50–100 gallons water, containing 30–80% copper hydroxide.
[11] In parts of Puerto Rico nearly 50% of cultivated coffee acres are affected by this disease, resulting in yield losses around 15%.
[12] Literature suggests that M. coffeicola is not a significant problem in Ethiopia and Uganda, Africa's top coffee-producing countries.