The influence of the protectant and mineral fertilizers on the contamination of crops and the disease infestation of hemp sowing plants

The research was conducted during 2017-2020 at the experimental field of the Federal Research Center for Bast Fiber Crops the Penza region. The results of laboratory and field experiments to determine the effectiveness of seed treatment with TMTD, VSK and Izagri Force fertilizer, as well as spraying with Izagri Phosphorus fertilizer of plants of monoecious hemp of the Nadezhda variety are shown. The studied factors influenced the seed contamination and the prevalence of root rot, and later on the infestation of crops and the intensity of leaf spot development. Seed treatment with TMTD, VSK (5.0 and 2.5 l/t) suppressed 95.3 and 85.5 % of seed infection, reduced the prevalence of root rot by 4.2 and 1.8 %, and the intensity of leaf spot development by 1.3 and 0.6 % compared to the control. A significant effect of the studied factor on the reduction of the air-dry mass of weeds in the phase of 6-7 pairs of leaves was proved by 31.9 and 26.4  % compared to the control. When using Izagri Force fertilizer for seed treatment (1.0 and 0.5 l / t), the biological efficiency of etching was 47.2 and 37.0 %. The prevalence of root rot decreased by 1.8 and 5.4 %, respectively, and the intensity of leaf blotches decreased by 1.6 and 1.1 % compared to the control. The application of the fertilizer allowed to reduce the air-dry mass of weeds in the phase of mass maturation of hemp seeds by 4.8 and 6.5 % compared to the control. Foliar top dressing with Izagri Phosphorus fertilizer for plant vegetation (3.0 l / ha) provided a reduction in the air-dry mass of weeds on average during the growing season by 17.4 % compared to untreated plants. The combination of all the studied factors when using TMTD, VSK and Izagri Force preparations in the consumption rates of 5.0 and 1.0 l / t against the background of foliar top dressing led to the suppression of weed vegetation, respectively, by 48.1 %.