Fine Coffee Science explains Coffee Leaf Rust in detail

Coffee leaf rust (coffee rust) is the most destructive disease of coffee trees, which is caused by coffee camel rust (Hemileia vastatrix).

The disease has long occurred in coffee-producing areas such as Africa, the near East and India, Asia and Australasia. It first appeared in the Western Hemisphere in 1970 and was found in Brazil. Once thriving coffee plantations in Sri Lanka and Java were destroyed by the disease.

Symptoms of coffee leaf rust: there are small yellow oil spots on the surface of coffee leaves, then expand into bright orange to red spots, and finally turn brown, with yellow edges, diseased leaves droop and gradually fall off, and the plant dies within a few years. Coffee leaf rust is very contagious.