Tests have been developed that detect diseases in plants. These include ELISA tests and antibody test strips. ELISA stands for enzyme-linked immuno-sorbent assay. It is commonly used to identify plants infected with a pathogen. Antibodies are produced that react to unique proteins produced by the pathogen.
These antibodies are placed in microwells where they produce a color reaction when exposed to plant extracts containing the pathogen.
In a similar reaction, test strips show a band on the strip in the presence of a disease.
Propagators use ELISA tests to maintain clean seed stocks, and to keep stock plants virus free for grafting, cuttings and tissue culture.