EN
A field experiment was conducted on a very good rye soil complex to study the effect of contact fungicides to control Phytophihora infestans on tuber yield and quality of six potato cultivars. The following fungicides were used: Dithane M-45, Miedzian 50, Cynkomiedzian and Cynkotox. Nitrogen rates were as follows: 0, 50, 100, 150 and 200 kg N/ha. The applied fungicides increased the tuber yield by 1.6 t/ha in cvs. Bronka, Dryf and Pilica and by 3.4 t/ha in cvs. Dukat. The effectiveness of the fungicides was highest when applied in presence of 100 and 150 kg N/ha. Application of fungicides in combination with high N rates increased the proportion of large tubers and decreased the proportion of seed potato. Tubers from the fungicide-treated plots contained somewhat more starch and vitamin C than those from the control plots.