Shendryk K. Etiology and pathogenesis of root rots of soya, biological foundation of means of restriction of their development in the Northern part of Forest-Steppe zone of Ukraine.

The object of research: causative agents of root rots of soya, resistance of varieties, preceding crops, fungus antagonists, biological and chemical methods of protection. The aim of research is to determine features of the development of soya root rots, species composition of the causative agents in the Northern part of the Forest - Steppe zone of Ukraine, evaluation of their pathogenic properties under different conditions of growing and foundation of ways of reduction of harmfulness of the disease. Methods of investigations are: field, laboratory, pot experiments and statistical studies. Means, which limit the development of the disease, were biologically founded; a more accurate definition and completion of the species composition of the causative agents of root rots during soya vegetation were given. Scientific novelty of the work is in studies on ratio of species of the Fusarium genus at different phases of soya ontogeny. Pathogenicity of principal causative agents of the disease at different temperature, moisture and acidity of the environment was determined. Resistance of locally adapted and promising varieties of soya to root rots was studied. Antogonistic relations between the fungi of the Trichoderma genus and dominating species of the causative agents of rots were established in vitro. Selecting action of biological formulations in relation to different Fusarii species was noticed. The efficiency of using chemical means was studied. The area of application: working out zonal recommendations for soya protection from injury by root rots. Branch of the use: agriculture