Evaluation of the influence of heavy metals on the degree of damage Cameraria ohridella Deschka & Dimič, 1986 leaf surface of Aesculus hippocastanum Linnaeus, 1753

Abstract

The work presents the results of research on effect of heavy metals (Zn, Cu, Pb, Cd) on degree of horse chestnut (Aesculus hippocastanum Linnaeus, 1753) leaf surface damage by chestnut miner (Cameraria ohridella Deschka & Dimič, 1986) caterpillars. Analysis of leaf blade damage of the forage plant species by C. ohridella was conducted for four years (2017–2021). The research covered all the main park urban ecosystems in Dnipro city where horse chestnut trees were planted. Monitoring was carried out during the three summer months, which corresponds to the main feeding period of the three most active C. ohridella generations (I, II, and III). About 96 samples were used and prepared for atomic absorption analysis to study the content of heavy metals in A. hippocastanum leaf blades. On the territory of the park ecosystems in Dnipro city, eight groups of model horse chestnut trees of 20–30 years of age were identified which have similar morphological and taxonomic features but different degrees of leaf damage by C. ohridella miner. Since the plantations of horse chestnut are mainly located in an urban environment, we conducted research to test the hypothesis about the influence of heavy metals on C. ohridella vital activity. Presumably, the content of heavy metals also affects the degree of leaf blade damage. In this regard, we conducted research on the content of heavy metals in A. hippocastanum leaf tissues. It was found that accumulation in the horse chestnut leaf tissues of four basic heavy metals (Zn, Cu, Pb, Cd) contained in all urban environments depends on the orographic features of the area where A. hippocastanum trees grow. It also was found that the higher in relief were located the horse chestnut plantings, the greater the percentage of their invasion by the miner, and this trend was observed during the three summer months. For example, in the Manuylivsky Park where horse chestnut trees are located at 56 m above sea level, the average leaf invasion by the miner in August is 14%; in the same month in Oles Honchar Dnipro National University Botanical Garden (149 m), the level of invasion was 78%. Research on the effects of heavy metals on C. ohridella populations also showed significant differences by the types of urban ecosystems. It was found that the higher content of heavy metals in the leaf tissues in a forage plant, the greater percentage of their surface damage by mines.