Effect of Sun Exposure of the Horse Chestnut (Aesculus hippocastanum L.) on the Occurrence and Number of Cameraria ohridella (Lepidoptera: Gracillariidae)

The study of the leafmining moth of the chestnut miner (Cameraria ohridella Deschka & Dymic, 1986) was carried out through the planting of the common horse chestnut (Aesculus hippocastanum L.) in the Main Botanical Garden of the Russian Academy of Sciences. The effect of various degrees of insolation of horse chestnut plants on leaf morphology and the composition of secondary metabolites, as well as the relationship of these parameters with the number and density of C. ohridella populations during the growing season, was studied. The solar influence, it was noted, had a significant impact. Thus, the largest number of the pests was recorded on the leaves of the sunlit side of the tree crown, and the smallest on the leaves of the shady part of the crown. The low content of polyphenols in the pool of secondary metabolites in the tissues of the A. hippocastanum leaves did not deter C. ohridella and poorly protected the plants from this miner, while the significant content of carbohydrates in the leaves reduced the resistance of chestnut plants to damage by the Ohrid leaf miner.