Developments in methodology of plant virus detection

As a general rule some form of polyclonal-antibody based enzyme immunoassay is still preferred for routine plant virus detection, but modifications may be necessary when increased sensitivity or specificity is required. In recent years new developments in antibody-based detection methods have mostly involved the provision of specific reagents, such as monoclonal antibodies or affinity-purified second antibody-enzyme conjugates which have helped to improve the sensitivity and specificity of the assays. Other kinds of tests (such as nucleic acid hybridisation) must be used when tests for virus coat protein are not appropriate. Recently, tests based on the polymerase chain reaction show great promise. There is no single universal test: assays must be devised and optimised for each pathogen. The challenge with all types of test is to make them quicker, less labour intensive, and —if possible — cheaper.