Complex thresholds of harmfulness of soil phytophages and features of protection of grain crops in the Forest-steppe of Ukraine

Abstract

Actuality. The study of qualitative indices and mechanisms of the formation of the entomocomplex of various taxonomic groups, as well as the development of protective measures against a pest complex, is the most relevant topic of research in the sector of the rural economy and needs further development. In particular, the limiting indicators of harmfulness of the main phytophagous species with an assessment of the compensatory reaction of cereals at different stages of plant organogenesis. The main reason for this is the imperfection of technologies and their adaptation to changes in the geoclimatic factors affecting the development of grain crops, and the survival of the main pests of winter wheat.
The goal of the investigation is to substantiate the complex system of application of complex thresholds of harmfulness of soil phytophages and determination of the features of protection of crops against pests in modern technologies of growing grain crops of Ukraine.
The materials and methods of investigation. Common methods of research in entomology, bioecology and plant protection, laboratory, vegetative, analytical and statistical methods for assessing the complex of
connections of features of biology, ecology and distribution of major harmful insects of winter wheat in the Forest-Steppe of Ukraine.
The results and discussion. The peculiarities of reproduction of the main pests on crops of cereal crops are highlighted and complex thresholds of harmfulness of soil phytophages are established. The analysis of the harmfulness of the modern plant of winter wheat, maize, rye, triticale in the forest-steppe of Ukraine was carried out. According to the indicators of seasonal and long-term dynamics of pest numbers, grain yield losses are determined.
It is reasonable to understand the distribution of entomological objects in agrocenoses, which often has a contagious form, is reflected in the indicator "area of maximum damage", for example, for soil phytophages, taking into account the radius of their daily movement. For current conditions of crop management, it is actual to determine the total need for pests in the diet by the actual population of the species at different stages of ontogenesis of cereals, in a specific area, in a certain period of agrocenosis formation, taking into account the proportion of plant pest nutrition that varies with time.
For different stages of pests, there are certain maximum values of daily movement, and consequently, crop losses are manifested mainly on the area of maximum harmfulness, determined by the formula given above. In the current conditions of agricultural development, highly effective use of advanced technologies and progressive systems for protecting crops from a complex of harmful organisms is of particular importance, and the formation and development of plants and the harvest of grain of wheat, rye, maize, triticale are adversely affected.
Application in the production of models for calculating complex thresholds of harmfulness of phytophages on crops of cereal crops, based on theoretical data on the dynamics of the number of insect larvae with different developmental periods, reliably allows quantitative changes in the entomocomplex in time and space. At the same time, the development and introduction of the harmfulness of soil phytophages into the production of micro and macropores is of particular importance, and it will be possible to determine the expected losses of cereals from pests in the forest-steppe of Ukraine.
Conclusion. In modern systems of protecting crops from a complex of harmful insect species, it is advisable to take into account the mechanisms of self-regulation and the factors that influence the indices of spatial migrations of phytophages, as well as the patterns of local manifestations of their harmfulness at different stages of plant organogenesis.
For all forms of farms with the observance of new field crop rotations and optimization of phytosanitary condition, it is necessary to introduce a remote structural and technological scheme of a combined automatic system for estimating seasonal and long-term fluctuations in the number of pests by energy trophic chains.