The results of laboratory and field estimate of stability of newly created potato breeding material against Globodera rostochiensis (Ro1) are presented. During 2016—2018, 640 breeding samples sent by the leading breeding institutions of the state, namely: the Institute for Potato Research of the NAAS of Ukraine, the Polessky research department the Institute for Potato Research of the NAAS, CJSC NGO “Chernihivelitkartoplya” and the Institute of agriculture of the Carpathian region were tested in laboratory conditions. Among the potato material we studied, most of the samples belonged to the Polessky research department the Institute for Potato Research of the NAAS — 305 (47.7% of the total), where 172 samples (56.4%) of the sent hybrids of the first and second year of the testing were resistance. A higher percent of the resistance of the breeding material was in the potato material of the Institute for Potato Research of the NAAS, which was 68.0% (115 breeding numbers). In laboratory conditions, most of the samples — 57.7% showed resistance to golden potato cyst nematode (GPCN), 16.2% of the samples were weakly resistant and the rest samples — 26.1% of potato hybrids were classified as susceptible. During the field testing, 32 samples were tested, of which 28 were classified as resistance, 2 selective samples were weakly resistant and 2 were susceptible. The majority of resistance selection material on the high-invasive background showed high nematode cleanse ability and good yield, which exceeded control in 1.5—2 times. All resistant forms are a valuable material for introducing into the breeding process for the production of nematode resistant potato varieties, which will keep the crop in the infected areas and will have the ability to clear the soil from golden nematode potatoes.

A survey of 11 domestic potato varieties in 2017 and 2018 in the spring after storage showed that the infection of the tubers of Ditylenhus destructor Thorne, 1945 did not exceed 0.5—7% in them. This allowed us to classify the studied varieties as a relatively stable group. The loss of harvest during storage in 2017 was from 1.0 to 6.4%; in 2018 from 0 to 3.3%. The accounts tubers affected by the D. destructor in 7 blighty potato varieties during the harvest period (October 2016) and after storage (March 2017) allowed to determine the level of development of the disease and to classify Chervona Ruta, Yavor, Tiras to relatively stable varieties, Slavyanka and Teterev — to medium — and two varieties Serpanok and Svitanok kievskii — in the receptive.

Optimum tank mixtures of fungicides (Thanos, v.h., Ordan, r., Shirlan 500 SC, KS) with biologically-active compounds — growth regulators (Biolan, r., Stimpo, r., Regoplant, r.), microfertilizer (Oracle, p.), which allowed to reduce the rate of application of fungicides by 50% and to ensure the improvement of quality indicators and increase of potato yield. Investigated biological, economic and economic efficiency, methods, frequency and timing of the optimal use of tank mixtures of fungicides and the reaction of potato varieties to use them.