The silverthread disease attacks Coffea arabica as well as C. liberica. It forms rhizomorphous strands, which grow acropetalous, and at the nodes of the branches, they spread over the under side of the leaves. The hyphae clog the stomata; no sooner are the guard cells killed, then they also penetrate the leaf. Brown spots arise on the leaves; finally these wither completely and hang from the top of the branches by the myoel strands. The fungus does not show any fructification; the mycelium has some typical characteristics. Artificial inoculation gave positive results. It is not identical with Pellicularia Koleroga, nor with candelillo, the same disease exists in Porto-Rico. Spraying with Bordeaux Mixture is a good means of combating it.