Features of development and prevalence of diseases on soybean in the forest-steppe of Western Siberia

Abstract

In recent years, there has been a significant deterioration of phytosanitary situation in plantings of many agricultural crops, including fodder crops. One of the valuable forage crops is soybean, which is becoming increasingly widespread outside its natural climatic zone. Under the conditions of Western Siberia, soybean crops are almost annually affected by a complex of diseases that significantly reduce the yield and quality of the seed material, which requires a comprehensive approach to ensure a minimum infectious background in crops. The development of epiphytotics on crops follows a certain dependence. The peak incidence of fungal infections is associated with increased temperature and humidity. Bacterial infections have a greater tolerance to low temperatures and may develop during the final phase of soybean vegetation. We investigated the correlation between the incidence rates of fungal and bacterial diseases of soybean and weather and climatic conditions of all the years of research. The research was conducted in 2016–2022 in the Novosibirsk region. The choice of the years of research is due to the formation of established populations of soybean phytopathogens that cause annual epiphytotics. SibNIIK 315 soybean variety was used as a sample for the study of the disease incidence in soybean crops. Based on long-term studies, this variety is the most affected of all the varieties. The leaf-stalk infections such as false mildew and pustular bacteriosis were considered as countable diseases. The use of correlation analysis to establish the degree of interrelation between the main indicators of soybean crop infestation and weather and climatic conditions of the growing season allowed to reveal a certain relationship – mainly due to the fact that fungal infections in all the years of research were manifested by the type of the epiphytotics. However, this method is not well suited for low prevalence diseases and diseases with short-term outbreaks.