Analysis of the prevalence and development of major fungus diseases of soya in the Primorsky krai
The formation of a system for managing the phytosanitary state of agroecosystems based on integrated plant protection requires the development of an assortment and determination of the needs of crop production for plant protection products. The need for plant protection products and their assortment are determined by the existing structure of sown areas of agricultural crops, their phytosanitary status and trends of its change in the future in connection with the existing economic conditions for the production of the reformed agricultural sector and the peculiarities of climate change. Thus, one of the main elements of phytosanitary technology is phytosanitary monitoring, which is the goal of the work done. Currently, among the factors restraining the growth of soybean productivity, the most significant are fungal diseases. Monitoring of soybean agrocenoses in four agroclimatic zones of the Primorsky Territory, conducted annually by the Far East Research Institute of Plant Protection, shows that in the last decade, under the conditions of agricultural reform, there has been a significant destabilization of the phytosanitary state of crops culture. The research paper presents the findings of a longterm investigations (2009-2018) on the species composition of soy diseases in various agroclimatic zones of the Primorsky Territory. The most harmful to the culture are the diseases of roots and root part of the stem. The development of root rot on seedlings of soya in all years of research was epiphytotic in nature and reached an average of 16.4-40.4% over the years. As surveys have shown, septoria fungus dominated everywhere on the Territory. Its prevalence reached 100% annually, and the intensity of development amounted to 27% on average. Also, peronosporosis and cercosporosis were observed annually in soybean crops. The degree of manifestation of these pathogens was intense. The level of development of peronosporosis and cercosporosis during the years of research averaged 24 and 19%, respectively.