Seliutina O. Bio-ecological features of the horse chestnut leaf miner (Cameraria ohridella Deschka & Dimic, 1986) in the steppe zone of Ukraine

In the dissertation work, the features of Cameraria ohridella (Lepidoptera, Gracillariidae, 1854) invasion were studied in various park urban ecosystems (on the example of Dnipro city). The study shows a reliable dependence of the degree of leaf blade damage on height above sea level at which the park urban ecosystem is located. Dependence between number of leaf mines and concentration of heavy metals (Zn, Cu, Pb, Cd) in various park urban ecosystems was found. In the park areas that have the highest heavy metal concentration in Aesculus hippocastanum L. tissues, there was also a large number of mines on the leaf blade. Maximum values of the mine number on individual leaves of A. hippocastanum reached 450–465. Leaf damage dynamics, content of high soluble proteins, activity of peroxidases and composition of acidic isoforms of enzymes in the leaves of A. hippocastanum were analyzed on exposure to C. ohridella. Destruction of leaves on relatively stable horse chestnut trees caused by the miner increased during July-August to 13.3%, while in unstable trees this value reached 97.5%. In July, maximum amount of proteins in the leaves of A. hippocastanum was found, this value significantly decreased in August and correlated with the level of leaf damage caused by C. ohridella. The damaged horse chestnut leaves were characterized by increased cytoplasmic peroxidase activity more than twice when a level of leaf damage by phytophage was high. These findings indicate that damage of the leaves by C. ohridella resulted in oxidative stress which leads to enzyme activation. In the leaves of A. hippocastanum trees having high-level damage by the miner, expression of the enzyme isoforms is significantly activated within the pH range of 4.08–4.15, which can be considered as a reliable biochemical marker of A. hippocastanum plants sensitivity to the phytophage C. ohridella attack. High total activity of peroxidase established by us, as well as the active rearrangements in the spectrum of peroxidase system obviously contribute to the maintenance of functional integrity of the photosynthetic system in leaves A. hippocastanum under C. ohridella influence through the neutralizing of reactive oxygen species.