The features of the formation of the population of Agrotis segetum Schiff. at crop rotation in the Forest-Steppe of Ukraine

Abstract

The article represents the seasonal and multinational dynamics of the popularization of Agrotis segetum Schiff. in the Forest-Steppe of Ukraine.

The influence of the hydrothermal coefficient on quantitative and qualitative changes in the population of phytophagous is analyzed. There is a determine of the peculiarities of pest development depending on the sum of effective temperatures and solar activity and geophysical processes and effect of earth's magnetic field, in modern populations of the turnip moth in this article.

In the new field crop rotation, modern populations of turnip moth are characterized by periodic outbreaks of mass reproduction, with phytophagous populations of large areas and a credible increase in harm to crops of agricultural crops. So reliable outbursts of mass pest reproduction for the last 159 years have been registered 17 times with the average cycle of populations of 9 years, which should be taken into account when forecasting the size of the pest in farms of all forms of ownership. However, the lack of generalization of theoretical foundations of the mechanisms of dynamics of the number of this phytophagous with the newest remote forecast of the phasic condition of the pest contributes to the optimization of protective measures in the field crops of the Forest-Steppe Ukraine. The modern features of the biology and ecology of Agrotis segetum Schiff. deserve attention - polyphagia, polyvoltism, stretch of the fly imago, hidden tracks in the soil on the ground with the laws of appearance and survival in the short rotational field crop rotations.

At the same time, improving the methods for detecting and counting the number and distribution of winter shoots, justification of new effective models of the forecast will improve the efficiency of systems of protection of crops from phytophagous to the Forest-Steppe Ukraine.

It is worthwhile to note that turnip moth is found mainly in areas with high humidity. The northern boundary of the moth in Europe coincides with the isotherm of the sum of effective temperatures of 500^oC, which are necessary for the development of one generation. In the northern agrocenoses of Ukraine, turnip moth develops in one and two generations, and in Southern regions - to three, the greatest harm is characteristic of the second generation. It is known that from the provision of pests with a high-quality and easily accessible base for nutrition, along with abiotic factors, the turnip moth can form up to two generations.

The development of the pest on the straight line correlates with the hydrothermal coefficient index (HCI), the highest level of harm is characteristic for agrocenoses from HCI 1.0-1.2, which is characteristic for the wet climate of the Forest-Steppe zone of Ukraine. The evaporation of the inhomogeneous steroids of the HCI over a coefficient of 1.2 or less than 0.9 is negatively influenced It is based on the viability of the pests of the pest that corresponds to the zone of Steppe and Polissya. An increase in the number of pests is possible under the conditions of an optimal hydrothermal life for at least two years, but even in the unfavorable conditions for the development of the pest on in each of the above-mentioned lands, there was an increase in the number of populations. Thus, for years with optimal abiotic factors, the effect on the population of the turnip moth is characteristic, there is an intense passage of the phases of ontogeny in for the formation of the entomocomplex.

 Agrotis segetum Schiff. intensivelies occupies trophic niches, with indicators of high reproductive potential and wide specialization.

It is known that the species composition and number of Agrotis segetum Schiff. In different years, the cultivation of crops, depending on their tillage, weather and climate conditions on the region, are changing. Populations of turnip moth are characterized by life cycle changing in numbers due to intra-population and other mechanisms.

The sum of effective temperatures favorable for the normal development of the pupal stage varies from 220 to 270 ° C, and the optimal number of effective temperatures that affect the duration of the periods is 1800-2000°C

It is established that the summer of the imago begins mainly with the onset of air temperature + 17°C ... + 18°C and soil + 18°C ... + 20°C, in turn, begins in the third decade of March, and the mass flying in the first decade of April at the average daily air temperatures + 20°C ... + 22°C. The duration of the fly is imago.

The phenology of the insect has been specified, depending on the abiotic factors.

Modern changes in the population dynamics of the turnip moth is depending on the fluctuations of the abiotic factors, in particular solar activity, geomagnetic indices and hydrothermal coefficient, and systems of measures for the protection of field crops that should be taken into account during modeling, as well as remote prediction of the population and development and stability of the populations of the pest in agrocenoses.

The use of modern pest monitoring with the use of sensors, low-frequency photo traps and unmanned aerial vehicles contributes to the timely conduct of the forecast of the number of phytophagous and insurance of crops in the early stages of populated phytophagous plant growth, with the effective application of both the chemical and biological methods of controlling the winter shoots in the Forest-Steppe of Ukraine.