Kaminska O. Toxinogenic Micromycetes of Fusarium Fungi, Biological Substantiation of Measures to Limit the Accumulation of their Secondary Metabolites in Winter Wheat and Corn in the Right-Bank Forest-Steppe of Ukraine

The dissertation is devoted to studying levels of infection of winter wheat grain with fungi of the genus Fusarum and the species composition of pathogens, toxinogenic properties of fungi of the genus Fusarium, studying the content of secondary metabolites in grain of winter wheat and corn, establishing toxicity levels of grain infected with pathogenic fungi, analyzing the risks of producing toxins in corn grain before storage. According to the results of a three-year field experiment, it was determined that a high infectious background of fungal etiology for winter wheat after the corn precursor poses a serious danger to the infection of grain and the production of mycotoxins even in the field. As a result, a large amount of deoxynivalenol and T-2 toxin was recorded in winter wheat in the control groups of crops. It is proved that more formation of toxins was observed with endophytic damage to the grain with mycelium of the fungus. This fact was affected by the degree of damage to the grain and the period of contamination of the pathogen on it. The simultaneous accumulation of dangerous concentrations of several toxins deoxynivalenol and zearalenone in 25 % of the samples or deoxynivalenol, zearalenone and T-2 toxin in 16.7 % of the tested wheat grain samples was observed. This was facilitated by a high degree of damage to the grain by fungi of the genus Fusarium ‒ from 31 to 37 %. As a result of mycotoxin contamination, 11.7 % of maize grains were unsuitable for food, technical purposes and export. It has been determined that the effectiveness of the use of fungicides during the growing season, in particular when seed treatment with Raxil Ulta FS (tebuconazole 120 g/l) is combined with the treatment of crops in the flowering phase with Baizafon (triadimefon 250 g/kg) of the triazole class. The essence of the improvement lies in the method of purification of extracts using column purification with silica gel, which has shown high specificity for toxins: T-2 toxin, zearalenone, deoxynivalenol.