Coffee is attacked by over 300 diseases and a number of insects. In certain areas the coffee industry is no longer viable because of pests, and in all other areas pests represent a serious threat to yields.
The leaf rust fungus is a native of Northeast Africa but during the 19th Century it spread to many other parts of the eastern tropics. In 1869 it appeared in Ceylon and in just 20 years most of the millions of plantation trees were destroyed. By 1876 the rust had spread to Java, where it devastated the coffee industry. The nascent coffee industry of India was also destroyed.
The coffee-bean borer (referred to in Brazil as the 'coffee plague'), coffee 'leaf-miner', and Mediterranean fruit fly are the most common insect pests. Of these, the 'leaf-miner' is the most serious pest in many Latin American countries, causing up to 50% loss in plant efficiency. Of the many diseases, by far the most destructive is Hemileia vastatrix, a fungal leaf rust which causes spectacular defoliation and crop failure.