The еffect of fungicides on the development of diseases and soybean yield in the Forest steppe of Ukraine

Abstract

Goal. To study the effectiveness of modern fungicides against the most common diseases of soybeans during the growing season and their effect on crop productivity in the Forest-steppe of Ukraine. Methods. Field, phytopathological, statistical. The experiments were carried out in the farms of the Kyiv region, belonging to the Forest-steppe zone of Ukraine. Spraying of soybean crops was carried out twice during the growing season in the phases of budding-beginning of flowering (51—55) and the formation of beans (71—75). Determined the development of diseases, the effectiveness of fungicides, crop yield. Results. The most common diseases of soybeans in the forest-steppe zone of Ukraine have been identified: Alternaria, downy mildew, Fusarium wilting, Septoria, and bacterial blight. The species composition of diseases and the degree of their development were largely influenced by the weather conditions of the growing season. The investigated fungicides Abacus mk.e. (pyraclostrobin, 62.5 + epoxiconazole, 62.5), Amistar Extra 280 SC, (azoxystrobin, 200 + cyproconazole, 80), Acanto Plus 28 c.s. (picoxystrobin, 200 g/l + cyproconazole, 80 g/l), Coronet 300 SC (trifloxystrobin, 100 g/l + tebuconazole, 200 g/l), as well as Impact K preparations, c.s. (flutriafol, 117.5 g/l + carbendazim, 250 g/l) and Koside 2000 w. g. (copper hydroxide, 350 g/kg) at the recommended application rates effectively limited the development of most fungal pathogens. The highest protective effect of 69.8—78.9% of fungicides was shown against downy mildew of soybeans, the lowest — 31.7—42.2% against Alternaria, which had the highest development in comparison with other diseases. Fungicide Koside 2000 w. g. at the level of 67% limited the development of bacterial diseases. The use of fungicides had a positive effect on the yield of soybeans. Due to the limitation of the development of diseases, the soybean yield increased by 21.2—30.3%, depending on the variant of the experiment. Conclusions. The use of fungicides significantly affected the limitation of the development of the most common soybean diseases in the Forest-steppe of Ukraine. The effectiveness of The effectiveness of the studied modern fungicides against peronospora, fusarium wilting, septoria was at the level of 60.2—78.9%. Fungicides most effectively controlled the development of downy mildew, less effectively — the development of Alternaria. The limitation of soybean diseases when using fungicides contributed to an increase in its yield by an average of 0.7—1.0 t/ha.