Poplars (Populus spp.) are of significant ecological and economic importance. Long-term breeding efforts were aimed mainly at obtaining fast-growing and productive plants and less considered resistance to pests. This study aimed to identify patterns of susceptibility or resistance to Saperda carcharias (Linnaeus, 1758) (Coleoptera: Cerambycidae) infestation among clones of Populus hybrids and pure species, focusing on the influence of their placement, seasonal development, stem diameter, height increment, and crossing combinations. Among 34 clones of poplar species and hybrids of Ukrainian and foreign selection, in 2019–2023 S. carcharias infested 14 clones every year. Six clones (‘Ivantiivska’, ‘Kytaiska × pyramidalna’, ‘Volosystoplidna’, ‘Novoberlinska-3’, ‘Robusta’, and ‘Lada’) were the most susceptible to the infestation by S. carcharias. The clones of all presented poplar sections and their crossing combinations, except the Tacamahaca and Leucoides cross, were infested. Greater height increment promoted the infestation by S. carcharias. Ambiguous results were obtained regarding the susceptibility of Populus hybrids compared to pure species to S. carcharias infestations. Considering infestation by S. carcharias and plant placement in the site, it can be concluded that the clones ‘Sakrau45-51’, ‘Deltopodibna’, ‘Rosijska’, ‘Slava Ukrayiny’, ‘Lubenska’, ‘Rohanska’, and ‘Nocturne’ are resistant to this pest. Selecting native species clones or creating mixed clone plantations could enhance the resilience of poplar plantations to pest threats.

Poplars (Populus spp.) are of significant ecological and economic importance. Long-term breeding efforts were aimed mainly at obtaining fast-growing and productive plants and less considered resistance to pests. This study aimed to identify the patterns of susceptibility to Saperda carcharias (Linnaeus, 1758) (Coleoptera: Cerambycidae) among Populus hybrids and pure species, considering crossing combinations and some other traits. In our research, 35 clones of poplar species and hybrids of the Ukrainian and foreign selection from the Aigeiros, Tacamahaca, and Leucoides sections were tested in 2021 and 2023 in the plantation created in 2014 in Eastern Ukraine. S. carcharias preferred infesting clones with earlier foliage development, larger diameters, and height increments. Specifically, hybrids with American maternal lineage showed the highest susceptibility, whereas those with European maternal lineage or Asian origin displayed lower infestation levels or resistance, respectively. This variability suggests a complex relationship between genetic background and pest resistance, underlining the need for a deeper understanding of the factors influencing susceptibility to S. carcharias. Selecting native species clones or creating mixed clone plantations could enhance the resilience of poplar plantations to pest threats.

72 species of xylophagous insects were identified under the bark and in the wood of poplars and aspens, including Coleoptera (66 species), Lepidoptera (5 species), and Hymenoptera (1 species). There were 40 Cerambycidae, 19 Buprestidae, 7 Curculionidae, 2 Sesiidae, 3 Cossidae, 1 Siricidae species. 5 monophagous, 14 oligophagous, and 53 polyphagous insects were identified. The frequency of occurrence of all species is estimated. Single and rare species predominate (33 and 26 species, respectively). There were 9 common species and 4 abundant species. All abundant species are polyphagous. 3 figs, 1 tab., 46 refs.

Introduction Poplars and aspens (Populus sp.) are common in forest stands, shelterbelts, rural landscaping, and in special plantations as short-rotation woody crops; they are promising tree species for biofuel and bioenergy production. Wood-boring insects browse galleries in a stem or branches that interrupt sap circulation and promote infestation by plant pathogens. Some of these insects can additionally weaken trees using foliage, bark, or phloem for maturation feeding. All these effects comprise the physiological harmfulness of wood-boring insects, whereas their technical harmfulness depends on the size and depth of the galleries, their location at the stem, and the timber value of a given tree species. The approach of wood-boring insect harmfulness assessment was suggested by E. Mozolevskaya and it is implemented for oak, pine, spruce, birch, and elm. It was shown that the harmfulness of the same insect species varies significantly depending on environmental conditions and population density. The aim of the research was to evaluate the physiological harmfulness of xylophagous insects for Populus sp. in the Left-Bank Forest-Steppe considering the ability of these insects to colonize and damage trees under certain health, transmit the pathogens, as well as host range and occurrence. Materials and Methods The research was carried out in 2019–2022 in Poltava, Sumy, and Kharkiv regions at the archive plantation of poplar clones, forest stands, and forest shelterbelts. The collections and research of Yu. Skrylnik since 2006 in the specified territories were also included in the analysis. In the analysis, only those insect species were used, for which the development in the stems and branches of Populus sp. was proved by our research and/or supported by publications. The range of host plants and the occurrence of insects were estimated. Their physiological harmfulness was calculated as the sum of scores for their physiological activity (ability to colonize trees under certain health condition), ability to damage the trees during maturation feeding, and ability to vector the pathogens. Results and Conclusions In the study, 72 insect species were analyzed, particularly 40 Cerambycidae, 19 Buprestidae, 7 Curculionidae, 2 Sesiidae, and 3 Cossidae. The proportion of abundant species was the highest among Scolytinae: Xyleborini. Species with a high physiological activity predominate among monophagous insects, particularly, Agrilus suvorovi, Cryptorhynchus lapathi, Xyleborus cryptographus, Paranthrene tabaniformis, Acossus terebra. Only five species (S. populnea, S. octopunctata, S. perforata, S. scalaris, S. carcharias) can cause significant damage to trees during maturation feeding by foliage or bark of branches. The average score of physiological harmfulness is the highest among abundant xylophagous species, it is almost twice as low in common species, and almost two times less in rare and single species. High physiological harmfulness (10 and more) for poplars and aspens is estimated for nineteen xylophagous species, particularly, 13 for S. populnea and S. carcharias, and 12 for Cryptorhynchus lapathi, Trypodendron signatum, Tremex fuscicornis, and Xyleborini species. 3 Tab., 4 Fig., 35 Ref.

The data on the species composition of seed alfalfa pollinators, their trophic links, seasonal dynamics, and influence on alfalfa seed productivity were generalized. Among 47 solitary bee species of 15 genera and 6 families, 8 species comprised 87.9% of all bees visiting alfalfa flowers. These species have the highest abundance from the second half of June to the third decade of July, which coincides with the yellow alfalfa flowering after moving at the beginning of the budding stage. The average degree of pollination of alfalfa flowers was 25.4%, which delivers an average of 7.6 centner/ha of actual seed yield in commercial crops. 1 fig., 3 tabs, 57 refs.