Storage of samples infected with lettuce or cucumber mosaic viruses prior to testing by ELISA

Methods of processing and storing lettuce mosaic and cucumber mosaic virus infected tissues prior to ELISA have been examined. Virus antigen detection was highest in samples homogenised in phosphate inoculation buffer (1% K₂HPO₄, 0.1% Na₂SO₃) and stored at either — 20°C or — 196°C. Detection was poor in samples homogenised in phosphate buffered saline prior to storage and in samples of all treatments stored at 4°C. Freeze-dried leaf segments retained a high concentration of antigen, as did freeze-dried homogenates of samples prepared in inoculation buffer. Higher levels of antigen were detected in samples stored as whole leaves at 4°C for 24 h before processing, than in samples stored as leaf segments during this period.