Enumeration of rhizobia by enzyme‐linked immunosorbent assay (ELISA)

The use of the enzyme‐linked immunosorbent assay (ELISA) to enumerate rhizobia in peat carrier and in soil has been investigated. The ELISA technique takes less time than the conventional plant infection technique often used to enumerate rhizobia present in the presence of other micro‐organisms. A minimum of 10 2 –10 3 cells are required for a detectable ELISA reaction, limiting the use of this technique when the number of rhizobia is low.