Dependence of species composition and development of root rots pathogens of spring barley on abiotic factors in the Eastern Forest-Steppe of Ukraine

Root rots of spring barley have become widespread and cause a significant damage to agriculture. The poorer the culture of agriculture is, the higher are the losses from the root rots. Non-observance of crop rotation, the presence of monoculture of one or another species of cereals and poor agricultural technique lead to deterioration of the structure and depletion of the soil, create the unfavourable conditions for the development of plants, and facilitate the accumulation of pathogenic fungi in the soil and plant remains. Abiotic factors significantly affect the species composition and pathogens of the root rots, which requires the specification of these indices parameters, especially under the conditions of the Eastern Forest-Steppe of Ukraine. We have found that Helminthosporium and Fusarium root rots of spring barley are the most widespread in the zone of the Eastern Forest-Steppe of Ukraine, the pathogenic organisms of which are fungi of the genus Drechslera spp. and Fusarium spp. The development and prevalence of root rots directly depend on the weather conditions during the vegetation period of spring barley and are intensified with a considerable amount of precipitation, high air humidity (60-80%), moderate temperature (19-20 degrees C), and hydrothermal coefficient of 1,2-1,4. Under the conditions of the Eastern Forest-Steppe of Ukraine these diseases are taking their dynamic courses with a significant increase in the later stages of the plant-feeder development.