Phytosanitary Monitoring and Biological Effectiveness of Fungicides in Agrocenoses of Potato Varieties in the Conditions of the Non-Chernozem Zone

Due to diseases, the yield loss of potato crops in the Russian Federation is on average 15-20%, and depending on climatic conditions, in some areas, it can reach up to 30%. The aim of the research is to assess biological effectiveness of fungicides on potato varieties cultivated in the Ryazan region, which has been carried out in 2022-2024. The soil on the experimental plots is dark gray forest soil. The objects of the study are three medium–ripened potato varieties, that is the Lugovskiy, Utro, Prime varieties, and the Abiga-Pik, VC and Consento, KS fungicides. The research has been carried out by using standard methods. When treated with Abiga- Pik, VC fungicide at a dose of 2.5 l/ha and 3 l/ha, the rate of late blight has ranged from 0.1% to 0.4% without significant deviations. In the variant with the Consento, KS fungicide at a dose of 2 l/ha, the development of late blight in the three varieties has ranged on average from 0.1% to 0.3% over the years of research. In terms of biological effectiveness, when treated with the Abiga-Pik, VC fungicide, the highest rates for the three studied varieties has been revealed after using a dosage of 2.5 l/ha and 3.0 l/ha – 90.7-98.6% and 91.1-98.3%, respectively. The highest indicator of the biological effectiveness of the Consento, KS fungicide has been achieved at a dosage of 2.0 l/ha – 97.9-99.2%. The highest density of potato plants is observed in the Lugovskiy variety, when using Abiga-Pik, VC fungicide 46.8 thousand units/ha and 47.1 thousand units/ha when using the Consento, KS fungicide, which is higher than the control variant by 21.2% and 21.3%, respectively. In the experimental variants, the number of potato tubers of the Lugovskiy variety has been 8.7 pcs after using Abiga-Pik, VC fungicide, and in the control variant it has been 9.1, and 7.5 after using the Consento, KS fungicide. When using fungicides, a significant increase in the yield of potato tubers of the Lugovskoy variety has been established after Abiga- Pik, VC with a rate of 2.5 l /ha plus 85.4 c/ha or 41.9 % to the control. When using the Consento, KS, the increase in the Lugovskiy variety yield relative to the control has reached 66.7 c/ha or 32.7 %.