Abstract
Two hundred and nine strains of Pseudomonas solanacearum were obtained from potato fields in Nagasaki, Japan, at periodic intervals late in the growing season on the fall crop. Thirty seven strains were classified as biovar II, one as biovar III, and 171 as biovar IV. The percentage of biovar II strains increased in the latter period of the growing season. In static culture at 16.5C, biovar II strains grew more rapidly than those of biovar IV. Biovar IV grew more at 35C for four days than at 24C for seven days and 16.5C for 14 days. However, biovar II did not show clear difference of growth at 16.5C for 14 days and 35C for four days. There was no difference in the latent period between biovar II and IV strains in inoculation experiments. Biovar II and IV strains were considered to be race 3 and race 1, respectively. This is the first report of race 3 of P. solanacearum in Japan.
