According to the results of phytopathological records on the specification, distribution and harmfulness of the black leg of potatoes, the territory of Ukraine is divided into three zones: a) strong disease development, where the number of affected plants exceeded 5 % and tubers after harvest – 10 % (northern and central Polesie, foothills of the Carpathians, Bukovina); b) moderate development of the disease, where the number of diseased plants reached up to 5 % and the tubers exceeded 7 % (southern Polesie, forest-steppe zone); c) the zone of insignificant development of bacteriosis, which did not exceed the number of affected by the black leg of plants 2 %, and tubers – 4 % (zone of the Steppe). The symptoms of black leg on potato stems were manifested in the form of wilting and rotting of the stems. In the diseased plants, yellowing of the lower leaves, the base of the stems and the root system, depending on the resistance to the pathogen of the varieties, became dark, brown or dark green. The main source of infection, with the defeat of the potato black leg, were diseased planting tubers
potato, diagnostics, infection, sort-varieties agent of disease