The dependence of the biological efficiency of soybean seed treatment with fungicidal seed dressings of different mechanisms of action on the conditions of the year in the forest-steppe of Western Siberia

Abstract

The results of a study on the assessment of the biological effectiveness of fungicidal soybean seed dressings with different mechanisms of action, taking into account the conditions of the year, are presented. The objective of the study was to establish the influence of seed dressings with different mechanisms of action and seasonal conditions on the development of soybean root rot in field conditions. The studies were conducted in 2020–2024 in the northern forest-steppe conditions of the Novosibirsk region using the generally accepted methods. The field experiment was carried out in four replicates. For the research, the systemic seed dressing agents Bariton (prothioconazole 37.5 g/l + fluoxastrobin 37.5 g/l) at a rate of 1.5 l/t and Scarlet (imazalil + tebuconazole (100 + 60 g/l)) 0.4 l/t were used, as well as contact preparations Maxim (fludioxonil 25 g/l) 2.0 l/t and Delit Pro (pyraclostrobin 200 g/l) 0.5 l/t. On average, over 5 years, the development of root rots in the first half of the growing season exceeded the harmfulness threshold by 2.5–5.3 times, and in the second – by 2.0–3.6 times. The maximum values were recorded in 2022 and 2023 with the highest hydrothermal stress. On average, over 5 years, the biological efficiency of seed treatment reached 67.2% in the germination phase and 36.7% in the flowering phase in the variant with the Maxim preparation at 2 l/t. In conditions of moisture deficiency, contact preparations had a higher biological effectiveness against soybean root rot, while in the years with sufficient or excessive moisture, systemic preparations had a higher biological effectiveness.