Recent Developments In Serology And Electron Microscopy For The Diagnosis Of Plant Virus Diseases

One ol the important prerequisites to the management of virus diseases is the precise identification o f the C~USa~geIn t. Diagnosis of viral diseases n3w demands a wide variety of skills which are constantly being improved as a result of rapid technological advances. By the introduction o f increasinglv sensitive serological methods and transmission electron rnicro- *copy, i t is now pomible to detect viruses that are present in plant tissues in extremely low concentrations. Many early reports on the occurrence of viral diseases have been largely based on visual symptoms and host range. External symptoms of diseases associated with spiroplasma, rickertsiae, mvcoplesma-like organisms and even nutrient deficiency symptoms have been confused with viral diseases. In addition. external symptoms produced by viruses can b4 greatlv influenced bv such factors ss genotype, plant age, environment and strain of virus present