The production of grapes is not a major agricultural industry in Utah, but in some areas of the state the crop is an important adjunct to the general fruit farm. This is particularly true in Washington County where European (vinifera) varieties are grown with considerable success, and in the north central counties where American (labrusca) varieties, especially Concord, are grown for the local markets. In this latter area the nutritional disease, chlorosis, is probably the most serious difficulty encountered in the development of a successful vineyard