Occurrence of Pseudomonas syringae pv. tomato in Bulgaria

M. Stoyanova1*, K. Aleksandrova1, D. Ganeva2, N. Bogatzevska1

1Institute of Soil Science, Agrotechnologies and Plant Protection, Nikola Pushkarov, 7 Shosse Bankya, 1331 Sofia, Bulgaria 2Vegetable Crops Research Institute Maritsa, 32 Brezovsko shose, 4000 Plovdiv, Bulgaria

Abstract. Bacterial speck of tomato caused by Pseudomonas syringae pv. tomato is an important disease in many tomato growing areas. The pathogen is known to comprise two races – R0 and R1. Sixty-seven pathogenic strains isolated in the period 2000 – 2013 from tomatoes with symptoms of bacterial speck in Bulgaria were the object of this study. The isolates were identified as P. syringae pv. tomato by the miniaturized Biolog system and possess the typical metabolic profile for the species. The pathogenic population of P. syringae pv. tomato in Bulgaria is homogeneous by phenotypic characteristics. The races of the strains were determined. On the base of the obtained results and the data available in the literature for the country, the proportions of the occurrence of the two races since 1985 alter cyclically with a tendency for shortening the cycle. The changes in the spread and development of the disease are related to the climatic changes.