Protection of hop plantations against causal organisms of root rot under conditions of changing climate factors

Abstract

Goal. To study the harmfulness of root rot and the tolerance of hop plants to its action using different control methods. Methods. Field — to inspect hop plantations, account and study the dynamics of the development of root rot of hops, assess plant damage, determine the effectiveness of preparations; laboratory — to analyze the affected hop plants; weight — to determine the value of the saved crop; morphophysiological — to establish biometric parameters of plants; mathematical and statistical — to assess the reliability of the obtained results, determine the correlations and calculations. Results. In 2016–2022, in the hop farms of Zhytomyr region, the species composition of root rot pathogens in hop agrocenoses was determined, among which fusarium (Fusarium humuli Kom.) dominated — 90%. Plenodomus humuli Kusnetz. affected 6%, Tuphula humulina Kusn. — 2%, Verticilium alboatrum Reinke et Berthold. and Bakterium tumefaciens Smith et Towns occurred only on 1% of affected hop plants. Analysis of the 5-year dynamics of damage caused by root rot agents of hop plants made it possible to determine the influence of changes in hydrothermal conditions on their distribution in the agrocenosis of hop plantations. It was proven that an increase in temperature by 1.5°C in the Polissia zone contributed to the specified spread of root rot of hops and increased its impact. The harmfulness of these types of diseases can increase several times during certain growing seasons. Watering maternal plants of hop with solutions of the preparations Impact 25 SC, k.s., 0.5 l/ha + Teravet, 7.5 g and Sclerotsid, r., 2.0 l/ha + Teravet 7.5 g ensured a reduction in damage by root rot pathogens of Zahrava and Ksanta varieties, respectively, by 0.30 and 0.35 points. Thanks to the fungicides, the spread of diseases was reduced by 45.5% in Ksanta varieties, and by 40.1% in Zahrava varieties. Conclusions. The level of spread and species composition of root rot in hop agrocenoses of the Zhytomyr region was determined. The change in climatic factors in the Polissia zone contributed to the spread of causative agents of hop root rot and increased their impact. The solutions of chemical and biological preparations entered into the soil effectively acted against the causative agents of root rot of hop plants, reducing their impact by 22–57% depending on the variety.