Bacterial speck of tomato caused by Pseudomonas syringae pv. tomato appeared to be recently the most important disease on tomato in Poland. The genetic relationships among four Polish strains of race 0 P. syringae pv. tomato of different origin, isolated from tomato plants, were examined by RAPD and PCR-RFLP techniques. Amplification of bacterial DNA using 33 primers with RAPD technique showed, that similarity of strains expressed by the Nei-Li coefficient was very high (above 0.8). Next, the restriction analysis of amplified region ITS with the use of 5 endonucleases revealed, that profiles obtained from electrophoretic separation of DNA fragments were also very similar. On the basis of those analyses it was concluded that all strains tested constituted a closely related group. However, they showed various level of virulence as was demonstrated on the inoculated leaves of tomato plants growing in the greenhouse.

Four tomato (Lycopersicon esculentum Mill.) varieties commonly grown by tomato farmers in Tanzania were evaluated for resistance to bacterial speck (Pseudomonas syringae pv. tomato) and bacterial spot (Xanthomonas vesicatoria) diseases, along with five introductions under screenhouse and field conditions. The four tomato varieties were Cal J, Moneymaker, Tanya and Roma VF. Seeds of the tomato varieties were purchased from seed vendors in the open market. The introductions that were included in the study were Bravo, Taxman, Stampede (from Sakata-Mayford Seeds (Pty) Ltd, South Africa), Torquay and BSS436 (from Bejo Zaden B.V., The Netherlands). In the screenhouse, results indicated that all the tomato varieties were susceptible to the two diseases, and suffered moderate to severe infection levels. The performance of the introductions against bacterial speck under screenhouse conditions was variable. All the introductions showed high levels of susceptibility to bacterial spot. Under field conditions, incidence of the diseases was high in all the locally available varieties tested, averaging 87% for bacterial spot and 82.3% for bacterial speck. The results of this study indicate that all the locally available tomato varieties included in the study were highly susceptible to bacterial speck and bacterial spot diseases.