Range of main species of phytophages and entomophages of cotton agrobiocenosis in lower reaches of the Zarafshan river.

. Numerous arthropods have adapted to live in various biocenosis in the process of evolutionary transformation, especially under the influence of anthropogenic pressure, in particular cotton, which is widely distributed in Uzbekistan, especially in the lower reaches of the Zarafshan river. Among them there is a large group of phytophages, which causes substantial harm to cotton. It is also home to predatory and parasitic insects, entomophages, which are their effective regulators. The long-term impact of the anthropic factor on the complex of phytophages and entomophages in cotton agrobiocenosis could not but affect their vital activity. Meanwhile, previous studies did not fully open the nature of interaction of individual groups of arthropod animals and did not take into account the changes that occurred in the transformed natural environment. The aim of the research is to study the species composition of arthropods, to determine the main species of phytophages and entomophages, their ecology and biological principles for regulating their numbers in cotton agrobiocenosis.


Introduction.
Numerous arthropods in the process of evolutionary transformation, especially under the influence of anthropopression, have adapted to living in various biocenosis, in particular cotton, which is widely represented in Uzbekistan, especially in the lower reaches of the Zarafshan river. Among them, a large group of phytophages is represented, which causes substantial harm to cotton. It is also home to predatory and parasitic insects, entomophages, which are their effective regulators [1].
The long-term impact of the anthropic factor on the complex of phytophages and entomophages in cotton agrobiocenosis could not but affect their vital activity. Meanwhile, previous studies did not fully disclose the nature of the interaction of individual groups of arthropod animals and did not take into account the changes that occurred in the transformed natural environment [2].
The mentioned provides a basis for studying the ecology features of the main species of phytophages and entomophages in cotton agrobiocenosis in the lower reaches of the Zarafshan river, which play a certain biological role under these conditions. At the same time, in order to improve the natural environment, research on the selection of environmentally friendly drugs on a microbiological basis is of significant importance, to which we also paid due attention, using the latest achievements of domestic and foreign scientists [3].
The aim of the research is to study the species composition of arthropods, to determine the main species of phytophages and entomophages, their ecology and biological principles for regulating their numbers in cotton agrobiocenosis.

Material and research methods
The studies were carried out in 2017-2020 in agrobiocenosis of cotton in the lower reaches of the Zarafshan River. Stationary work was carried out in cotton agrobiocenosis in Jondor district of Bukhara region.
Experimental observations were made annually for 4 complete generations of cotton moth, 10-14 complete generations of spider mite and cotton aphids. There were 3,973 specimens of cotton moth caterpillars under laboratory observation, from which 2,315 butterfly specimens were bred. More than 27 thousand specimens of eggs and caterpillars hatched from them were observed in insectarium conditions.
To determine the species composition of phytophages and entomophages, we collected more than 35 thousand specimens of arthropods.
To clarify the species composition of the parasites of gnawing and ground moths, we carried out growing in cages of caterpillars of different ages collected in nature, where the pupae of the pests were placed.
The species composition of parasites in cotton aphids was studied by collecting mummified individuals and breeding parasites in laboratory conditions [10].
In order to identify the population of cotton by the main phytophages and entomophages, to study the seasonal dynamics of the number of aphids, spider mites and their entomophages occurring in agrobiocenosis from the emergence of cotton seedlings to harvesting, we examined 20 plant samples every five days on plots of up to 5 hectares along the field diagonal (in a sample of 5 plants).
In order to detect cotton moth and other ground moths, 100 plants were examined in each field, located at equal distances along two diagonals. The number of eggs and caterpillars was taken into account [8].

Results
In the agrobiocenosis of cotton in the lower reaches of the Zarafshan River, 63 arthropod species belonging to 10 orders, 25 families, and 52 genera were identified. Among them, phytophages are represented by 31 species, and entomophages -32 (Table 1). The most widespread phytophages are Tetranichus urticae, Helicoverpa armigera, Aphis craccivora, A.gossypii, Acyrthosiphon gossypii. We attribute them, according to the system of F.M. Uspenskiy [7], to numerous species, which, in the lower reaches of the Zarafshan River, are the main phytophages that cause significant damage to crop production, in particular to cotton. The identified phytophages are included in 7 orders, 14 families and 28 genera. The most numerous phytophagous species is the Ortoptera order, which includes 4 families, 6 genera and 6 species. The order Homoptera includes 3 families, 10 genera and 11 species. The remaining orders are somewhat inferior to the previous ones in terms of the quantitative composition of taxonomic units.

Findings
Under conditions of anthropogenic impact, certain changes took place among phytophages. Thus, the construction of the Amu-Karakul and Amu-Bukhara canals contributed to the increase in the spread of the cotton bollworm. Previously, numerous species of Kyboasca bipunctata, especially Lygus pratensis and Lygus gemeleatus, are now widely represented due to the development of new lands for cotton and other agricultural crops. Meanwhile, numerous species of phytophages (Euxoa agricola, Spodoptera exigua) previously identified here by a number of authors [2,8,11] were absent in our materials. Some of the species noted by us are classified as potential phytophages (Acrosternum breviceps, Agrotes txclamationis, Dialognata nasuta), which, when the necessary conditions for their life are created, can take a place among the main phytophages of the lower reaches of the Zarafshan river. Among entomophages, according to the qualitative diversity of taxa, we distinguished the order Hymenoptera, consisting of 5 families, 8 genera, and 10 species, as well as the Coccinellidae family (order Coleoptera), which includes 5 genera and 7 species. The main entomophages are represented by 6 species (Scolothrips acariphagus, Coccinella septempunctata, Stethorus punctillum, Chrysopa carnea, Bracon hebetor, Serphus coroliae), which are widespread.