Micromycetes associated with wheat diseases in different regions of Ukraine.

The study is largely concerned with the micromycetes that represented the causative agents of harmful diseases of wheat and are severe challenges for grain producers in Ukraine. The potential yield of domestic commercial cultivars is 11-12 t/ha, but only 25-40% of their productivity is realized One of the main factors reducing the yield is ineffective disease control. Eyespot, take-all and sharp eyespot are among the most important diseases of wheat in Ukraine. However they are still underestimated in the country because of difficulties in their detection and causal agent isolation. Results of analysis of 37 Oculimacula strains, causal agents of eyespot, show the prevalence of the O. acuformis in northern regions, O. yallundae - in the south. Both species were detected in the central regions. The wide distribution (up to 100%) of Ceratobasidium cereale, a causal agent of sharp eyespot, has been observed all over the country. Gaeumannomyces graminis var. tritici, a causal agent of take-all, has been detected among darkly pigmented soil-borne fungi. Seed infection has been mainly presented by Alternaria, Fusarium, Penicillium, Helminthosporium and Mucor species. Pathogenicity of Fusarium strains has been confirmed in pathogenicity tests. The information has been obtained during surveys of winter wheat crops under different climatic conditions of Ukraine.