The specimens in the U.S. National Fungus Collections have been assembled from every major area of the world. They are used often for direct comparison with suspected pathogens. Approximately 100 loans are made each year for research throughout the world. Records for a recent, typical year show that services by the staff of the U.S. National Fungus Collections included assistance with fungal nomenclature and synonymy, fungal identification, herbarium specimen data, records of distribution and pathogenicity, information on mold prevention, information on mushroom poisoning and the eradication of mushrooms, and identification of poisonous mushrooms. Services were provided for such individuals as mycologists, plant pathologists, extension pathologists, and physicians as well as the lay public, and for institutions, including experiment stations, universities, biology publishing firms, research laboratories, government offices, museums, and hospitals.

The facilities, program, and staff of the U.S. National Fungus Collections are particularly strong for dealing expertly with mycological problems of foreign origin. The herbarium and major data files have been built up with emphasis on foreign material. Many compendia on foreign pathogens have been produced by use of these data. Support also is provided to the plant quarantine program of the Animal and Plant Health Inspection Service. As international travel and commodity shipments increase, continuing development of technical information on the mycology of foreign countries is necessary for plant protection in the United States.