Limitation of the development of powdery mildew in winter barley when using biological preparations in the conditions of the Western Forest-Steppe of Ukraine

Abstract

In modern conditions of climate change, there is an increase in the frequency of winter barley diseases, which necessitates the use of more resistant varieties and effective protection systems. Powdery mildew, the causative agent of which is the fungus Erysiphe graminis DC. f. hordei Em. Marchal, is one of the most common diseases of winter barley in the conditions of the Western Forest-Steppe of Ukraine. The use of a large number of chemical protection agents leads to a negative impact on the environment, the destruction of beneficial fauna, and the formation of resistant strains of pathogens. With severe damage, the yield of winter barley decreases by 10–15 % or more. In view of this, an important direction is the introduction of biological protection agents. Biological products stimulate the defense mechanisms of plants, improve their productivity and reduce the level of disease development. Seed treatment before sowing and application of products during the growing season have a positive effect on the condition of plants. Studies conducted at the Institute of Agriculture of the Carpathian Region of the NAAS of Ukraine included the use of such biological products as bactophit, trychodermin KS, trychodermin-93 at a rate of 2.0 l/ha, separately and in combinations. All options demonstrated a reduction in winter barley powdery mildew disease within 4.5–7.0 %; while control (absolute) had indicators
of 11.5–14.0 %. The highest efficiency 56.1 % in combating powdery mildew was shown by the combination of bactophit and trychodermin KS (2.0 l/ha each). This option also provided the greatest yield preservation – 1.0 t/ha. In the milky ripeness phase, on average over two years (2022–2023), the development of the disease in the control was 12.8 %, while with the use of biological preparations – 5.3–6.3 %. Biological preparations provided technical efficiency of 50.4–56.1 %, the highest with the combined use of bactophit and trychodermin KS. The yield of winter barley was also the highest with the combination of biological preparations bactophit and trychodermin KS – on average 4.3 t/ha. Seed sowing qualities: the mass of 1000 seeds was 49.6 g, germination energy – 85.5 %, laboratory germination – 95.3 %. Thus, the results of the studies confirmed the feasibility of using biological preparations to control powdery mildew in winter barley crops. The most effective option was the combined use of bactophit and trychodermin KS, which not only reduced the level of disease damage, but also ensured an increase in yield and seed quality.