“…As a result, there are American Type Culture Collection stocks of polyclonal (and many monoclonal) antisera available for most plant viruses that have been purified but relatively few antisera available for phytopathogenic bacteria or fungi. World-wide this has led to quarantine seed-testing, seed certification and virus indexing programmes based on the routine use of immunoassays for viruses (Hamilton, 1983;van Vuurde and Maat 1983;Mink and Aichlee, 1984;Torrance and Dolby, 1984;Raju and Olson, 1985;Lawson, 1986;Anonymous, 1987) whereas serological testing for bacterial or fungal pathogens in such schemes is not common (Anonymous, 1987). However, a number of research groups are beginning to produce antisera against important bacterial and fungal plant pathogens that are difficult to diagnose visually or are likely to be present in or on seeds or plant parts which require testing in certification schemes.…”