Сontrol of brown leaf spot for environmentally safe protection of grain sorghum in Ukraine

Abstract

Purpose. The purpose of the research was to determine the effectiveness of the complex application of biological preparations in grain sorghum crops to control brown spotting and their impact on the crop yield level in Ukraine. Methods. The study of the effectiveness of complex biological protection for the control of brown spotting of grain sorghum was carried out during 2018–2022 by conducting surveys of agrocenoses in the conditions of the educational and research field of the Polish National University and PE "Chaykivka" of the Radomyshl district of the Zhytomyr region. Field and laboratory methods were used to conduct the experiment. Results. The causative agent of brown spotting of grain sorghum is the fungus Helminthosporium turcicum (Luttr.) K.J. Leonard & Suggs. During the research, the first spots on the leaves were visible already in the first decade of June, and the development of brown spotting of sorghum did not exceed 1.6%. The disease reached its maximum development in 2022 and was 29.5%. It was possible to achieve the maximum reduction in the development of brown spotting in sorghum crops as a result of two-time spraying of the cenosis with biological preparations, which reduced the level of the development of the disease by 10.7% in the phase of milky-waxy grain ripeness. Complex application (two-time spraying with biopreparation Agat-25K, PA, 0.03 kg/ha and plant growth regulator Endophyt EM-1, v.s.r., 0.010 l/ha at the 30th stage of development) provided the maximum value of technical efficiency - 39.5%. The maximum productivity of the hybrid 419 x 124 was realized with environmentally safe protection of grain sorghum: two-time application of the biopreparation Agat-25K, PA, 0.03 kg/ha and plant growth regulator Endophyt EM-1, v.s.r., 0.010 l/ha on at the 30th stage of development, which was 6.24 t/ha. Conclusions. Due to the use of complex biological protection, we solved the urgent problem of ecologically safe control of brown spotting in crops of grain sorghum in Ukraine.