New potato wart Synchytrium endobioticum (Schilbersky) Percival pathotypes in Ukraine

Goal. Potato wart pathotypes determined and identified in Ukraine harmonized with requirements EPPO Standard for Synchytrium endobioticum. Methods. Soil samples were extracted according to the EPPO Standard scheme with an improved drill. The potato wart causative agents zoosporangium have conducted by flotation in sodium iodide solution. The existing pathotypes and isolates of disease causative agent identification conducted as per determining reaction of Ukrainian and European potato test-assortment on winter zoospores defeating of wart pathotypes of causative agents. Results. There were identified 5 pathotypes of wart causative agents: (D1) common, 11 (M1) Mizhirrya, 13 (R1) Rachiv, 18 (Ya) Yasynnya, 22 (B) Bystrets. The reactions conducted on Ukrainian potato cultivar-differentiators by winter zoosporangium of different pathotypes and isolates of potato wart. The analysis of researches for potato wart pathotypes conducted during 2021—2023. Wart causative agent isolate identification of t. Storozhinetz showed the difference of specified isolate from other existing disease causative agents in Ukraine. It was difficult to determine correctly Ukrainian pathotypes during by European potato test-assortment usage. Some European cultivar-differentiators (Combi, Saphir, Miriam, Giewont, Blanik, Irga, Evora Spunta) showed the same type reaction on Ukrainian causative agents pathotypes defeating. Conclusions. There were identified 5 pathotypes of wart causative agent by the Ukrainian potato test-assortment. The European test-assortment showed the same reaction on one-type reaction on Ukrainian causative agents of disease pathotype during their usage. We propose to renew the test-assortment for our Ukrainian causative agents disease pathotypes identifying for continue the researches for determining.