Кubyk M. Viral diseases of leaf apparatus of sugar beet and measures to limit their harm under conditions of Right-bank Forest-steppe of Ukraine

The thesis is devoted to studying of the spread and harmfulness of viral diseases of sugar beet in Right-bank Forest-steppe of Ukraine and improvement of the system for their control. Based on the analysis of experimental data, peculiarities of development of viral yellows and sugar beet mosaic depending on hydrothermal factors were established. The identification of pathogens was performed using indicator plants and PCR analysis. The influence of viral yellows and viral mosaic on growth of sugar beet plants, seed yield and fractional composition, root yield and sugar content in root, leaf surface area, chlorophyll content and ratio were investigated. Models of harmfulness of these diseases were developed. The role of agronomic measures in control of viral diseases of sugar beet was studied. It was established that spatial isolation between fields of factory and seed beet crops in 1000 m reduces infestation of plant with viral yellows in 1.4-2.1 times and with viral mosaic in 1.3-3 0 times. It is shown that fertilization can serve as one of the effective measures against viral diseases. Efficiency of modern seed toxicants and insecticides against the vectors of viral diseases of sugar beet was evaluated. Economical efficiency of their use was calculated.