||Caption: Periconia cookei - saprophytic, dematiaceous, anamorphic fungus. Periconia cookei grows on the stems of plants and produces a globose head on a straight, firm, hair-like stipe that becomes covered with a fuscous powder. Shown here is the hyphal stage of this fungus in the early stages of producing conidophores. It is difficult to phenotypically distinguish Periconia spores from the smuts, myxomycetes and other round, brown spore types. Periconia cookei is known to be a plant pathogen on bamboos in Asia and on ohia lehua trees in Hawaii. It is also known to be a mycoparasite on coffee rust (Hemileia vastatrix). Mycoparasitism, which is quite common in nature, has received special attention due to the search for biological control alternatives for diseases such as powdery and downy mildews. The coffee rust, Hemileia vastatrix, has been the most devastating disease of coffee cultivars and thus Periconia cookei has been studied for its potential biological control of rusts.