Phytosanitary condition of winter wheat agrocenosis in the Southern Steppe of Ukraine
Authors:   Odessa state agricultural experimental station of the National academy of agrarian sciences of Ukraine, Krivenko A. , Shushkivska N. ,   Bila Tserkva National Agrarian University of the Ministry of Education and Science of Ukraine
Published: January 2021

It is established that winter wheat belongs to the oldest crops and is the main food product in many countries. In Ukraine, the sown area of winter wheat is 5–6 million hectares. More than half of winter wheat grain production falls on the steppe zone. Cereal crops are damaged by insects in all growing zones, especially in the steppe zone of Ukraine. This is due to both the significant diversity of harmful species and the fact that in this area they reproduce most quickly and intensively. In addition, the lack of spring and summer precipitation exacerbates the negative significance of damage. Feeding insects on cereals causes a wide variety of damage, both in nature and in consequences for plants and crops. It is determined that one of the urgent problems of winter wheat protection is the study of patterns of dynamics of the number of major pests in modern agrobiocenoses. According to many scientists, global warming has affected the structure of entomocomplexes, as it optimizes environmental factors for the activities of insects, leads to their reproduction and spread. Harmful entomocomplex of winter wheat covers more than 360 species of insects. They damage the plants of this strategically important crop during all periods of growth. However, the species structure, level of dominance, number and harmfulness of insects are constantly varying, largely due to changes in climatic conditions associated with global warming. The article analyzes the phytosanitary status of winter wheat agrocenoses in the Southern Steppe of Ukraine during 2017–2019. The aim of the study was to determine the species composition and population density of insects in the modern entomocomplex with different technologies of growing crops in short-rotation crop rotations of the Southern Steppe of Ukraine. The research was performed in the research field of the Odessa State Agricultural Research Station of the National Academy of Agrarian Sciences of Ukraine. Observations and records were carried out in all phases of plant development during route inspections of winter wheat fields and adjacent fallows and other stations according to generally accepted methods of entomology and plant protection: mowing with entomological net, shaking of individual plants, test sites and test plants. The species composition of the detected insects was determined in the laboratory. According to the results of studies of the species composition and population density of insects in modern entomocomplexes, it was found that the vast majority of identified species – 78% belong to phytophages, 17% – to entomophages, 5% – to neutral species. Changes in the entomological complex and population levels of the phytophagous complex of the agrocenosis of winter cereals have been revealed. 46 species belonging to 19 families from 8 orders of the insect class were found in the harmful entomofauna. Significant fluctuations of entomocomplex structures in short-rotation crop rotation in the conditions of the Southern Steppe of Ukraine have been established. In particular, with the use of typical zonal technologies for growing crops, which lead to the reproduction of specialized pests.