The accurate diagnosis of a plant disease is the most important step in developing an effective management strategy for that disease. Yet diagnosing plant diseases is often difficult and frustrating. Distinctive symptoms may not develop until late in the disease cycle. Many plant diseases fail to produce obvious symptoms or produce general, nondescriptive symptoms, such as yellowing, stunting or wilting, that could be produced by a number of biotic or abiotic factors. Recent advances in molecular biology and biotechnology are being used to develop rapid, sensitive diagnostic kits for detection of plant diseases.