Worldwide distribution. On arabica and robusta coffee. An important disease.
Spots, 2-3 mm, expanding to 15 mm, with yellow-orange powdery blotches on underside. Later, spots on top turn brown with yellow halos. Leaves may fall and shoots dieback. Over-bearing dieback may occur if rust epidemics occurs on high-yielding trees. Food reserves from the tree are diverted to the berries and stem dieback results.
Spores spread by wind and insects, but need water to germinate. Possibly, new strain in Central America.