Assessment of deciduous trees state and phyllophagous composition in Yoshkar-Ola

This paper presents the results of long-term observations of the state of plantations of Betula pendula Roth and Tilia cordata Mill. in Yoshkar-Ola. Assessment of trees state was carried out by morphological analysis of the leaf blade, since the plants assimilation organs are most exposed to atmospheric toxicants, attacks of insects and pathogenic microorganisms. Based on the assumption that pollutants affect directly phytophages or through the forage resource, the species composition of the phyllophagous insects and mites was studied in the gradient of the increase in industrial transport emissions. Morphological changes in leaves and an increase in the area of damage in the pollution gradient are described. In this case, the area of the leaf blade can both increase in B. pendula, and decrease in T. cordata. Determination of the arachnoentomological material and the establishment of herbivorous insects and mites for characteristic lesions made it possible to describe in the crowns of B. pendula 84 dendrobiotic species, T. cordata 100 species. Among the phyllophagous there are gnawing and sucking leaves, miners and gall producers. The representatives of Coleoptera predominate. Under environmental conditions, the proportion of arthropods that are monophages and form protective devices increases. Under the conditions of the urban ecosystem, a decrease in the variety of phyllophages was revealed, but an increase in the relative abundance of the most protected species Aphidoidae (Homoptera), Cecidomyiidae (Diptera), Eriophyidae (Acarina). The calculation of the number of insects per unit volume of the crown was carried out. As a bioindicative indicator of the quality of habitat, it is suggested to use the state of tree leaves, the diversity and relative abundance of insects and mites of phyllophages.