Susceptibility to brown rot was determined in five potato cultivars. Valor cultivar showed high susceptibility followed by Spunta. Nicola and Desiree showed low susceptibility, while Daimant was moderate in this respect.The results of manuring showed that humic acid (2.9%), ammonium sulphate, calcium superphosphate and potassium sulphate decreased the growth of Ralston/a solanacearum at the tested concentrations up to 4%.Greenhouse experiments with Valor cultivar showed that all tested manurial compounds variably reduced the disease incidence. The most effective treatment was calcium superphosphate, followed by potassium sulfate and ammonium sulfate, respectively. Actosol (humic acid, 2.9%) was the least effective in disease control. The increase in tuber yield was recognized at significant level in all used treatments.