Genetic diversity of Erwinia carotovora strains isolated from infected plants grown in Poland.

losses of economically important plants. Potato blackleg, which is a tuber-borne disease, occurs during the growing season and is caused by E. c. atroseptica. Soft rot of potato tubers is usually caused by E. c. carotovora and E. c. atroseptica. As a result of the absence of resistant cultivars, disease control relies primarily on the production and use of healthy seed potatoes. Selection and elimination of infected material is very difficult as infection almost always appears in conditions favourable for disease development. About 1500 strains of pectinolytic Erwinia were isolated from plants and tubers with disease symptoms obtained from Control Inspectors of the Polish State Inspection of Plant Protection. Biochemical, immunological and molecular methods were used to estimate E. c. atroseptica and E. c. carofovora. About 57% of the isolated bacteria belong to subspecies atroseptica. ELISA testing with monoclonal antibodies indicated that only about 65% of these E. c. atroseptica isolates belonged to serogroup I.