Diversity of the entomocomplex of the grass stand of a hemp field in the North-Eastern forest-steppe of Ukraine

The agrobiocenosis of the grass stand of hemp field is a specific plant biotope, which is a place of shelter, feeding, resettlement, and breeding for many insect populations, which in one way or another affecting the growth, development and yield of hemp plsnts. Taking this into consideration awareness of the species composition of phytophagous insects as well as the complex of their natural enemies and neutral species became especially relevant awareness due to the necessary to develop an effective system of protection of hemp in the context of current conditions. The aim of the research is to improve the ecologically oriented system of hemp protection by means of studying the taxonomic composition of entomofauna in the grass stand, as well as the trophic and ecological structure of insect groups associated with that habitat. The studies was conducted in 2019-2021 on the basis of the Northeast Agricultural Institute of the National Academy of Agrarian Sciences out during the vegetation of plants by means of mowing with a standard entomological net every ten days, from 10.00 till 15.00 o’clock when the insects were the most active. The current taxonomic composition of entomocomplex of the grass stand in hemp field is represented by 174 species of insects that belong to 76 families and 9 orders. The Coleoptera turned out to be the largest in terms of the species diversity and the number of individuals (56 species from 16 families and 74.6% of the number of captured insects). Were also detected insects from the orders Hymenoptera (31 species from 15 families), Hemiptera (30 species from 11 families), Diptera (20 species from 12 families), Homoptera (17 species from 8 families), Lepidoptera (12 species from 8 families), Orthoptera (4 species from 3 families), Neuroptera (3 species from 2 families), Thysanoptera (one species) were also detected. In the trophic structure of the entomofauna in grass stand of hemp field, 85.9% of the number and 59.8% of the species diversity account for phytophagous insects. Pests of hemp were 39 species of insects from 22 families, and 6 orders. Among them, 36 species, which accounted for 18.7% of the total number of specimens, were polyphagous and three, or 81.3%, were specialized species. The presence of insect pests in the grass stand of hemp field was characterized by oligodominance, as evidenced by quantitative and qualitative data, and indices of species diversity. Thus, the dominance structure is represented by one eudominant (Psylliodes attenuata – 81.1%), one subdominant (Mordellistena parvula – 4.72%), four recedents (Lygus pratensis, L. rugulipennis, Lygocoris pabulinus, Stictocephala bisonia – 8.6%) and, 33 subrecedents (5.58%). The obtained research results will be used in order to solve the problems related to the danger of basic phytophagous insects during the vegetation period of cannabis sativa plants and to develop a modern environmentally-oriented strategy to control their numbers and harmfulness