Modification of a semi-selective medium for the isolation and quantification of Pseudomonas solanacearum.
A modified form of a selective medium developed by Graham and Lloyd (SMSA) was compared with the original medium (GL) and with SM-1 medium for plating efficiency, reduction of saprophytic soil microorganisms and recovery of P. solanacearum from artificially infested soil. The plating efficiency on GL was better than on the other 2 media, but it did not reduce soil microorganisms as well. Recovery rates varied from 36-99%. Some soil microorganisms influenced colony appearance on SMSA. It is concluded that the identity of suspect colonies on this medium should be verified on TZC medium or tested for pathogenicity.