This booklet is designed as a quick guide for identifying wheat and triticale diseases in the field. It is intended primarily for agricultural researchers, technicians, and farmers in developing nations, but will also be of value to others. The text comprises a brief description of the major wheat and triticale diseases, insect pests, nematodes, physiologic and genetic disorders, and mineral and environmental stresses. Complementing this text and as an aid to identification are numerous color photographs1, drawings2 and, in the center of the booklet, a brief diagnostic key. In the case of specific causal organisms, the perfect stage name or telemorph (when known) is followed by the imperfect stage name or anamorph in parentheses. While most of the diseases, pests, disorders, or stresses included can be economically significant, some are not and are presented only because they are unique or might be confused with more economically significant problems.