# Foliar Illumination Affects the Severity of Cameraria ohridella Damage Among Horse Chestnut Species

## TL;DR

This study shows how leaf damage from a leaf miner insect varies in different horse chestnut species based on how much sunlight their leaves receive.

## Contribution

The study introduces how foliar illumination affects leaf miner damage and resistance in horse chestnut species using physiological and hyperspectral methods.

## Key findings

- Species like A. pavia and A. chinensis showed higher chlorophyll levels and resistance to leaf miners in shaded areas.
- Higher proline levels in less-infested species suggest a link to resistance against leaf miners.
- Hyperspectral indices DSWI and SIPI effectively assessed leaf damage and resistance in horse chestnut species.

## Abstract

The influence of crown illumination on leaf damage of horse chestnut species (Aesculus hippocastanum L., Aesculus glabra Willd, Aesculus flava Aiton, Aesculus pavia L., Aesculus × carnea Hayne, Aesculus parviflora Walter, Aesculus chinensis Bunge) affected by ohrid leaf miner (Cameraria ohridella Deschka & Dymić) was studied using some accessions from the arboretum botanical tree collection. A. hippocastanum, A. glabra, A. flava had the lowest chl a content in the foliage on the sunlit side of the crown, while in A. pavia, A. parviflora and A. chinensis this indicator was the highest. The chl a content in the leaves of A. hippocastanum and A. flava under shaded conditions was 1.3 and 2.4 times higher than in the sunlit part, while in A. pavia, A. parviflora and A. chinensis the chl a content on the shaded side was 1.2, 1.6 and 1.3 times lower. The quantitative content of chl b in the sunlit part of the crown in A. hippocastanum and A. flava was significantly higher than in the other species. Moreover, while A. flava and A. parviflora had the highest chl b content in the foliage of the shaded part of the crown, A. glabra and A. × carnea had the lowest. Similarly, differences in proline levels were found in the leaves of different horse chestnut species on the sunny side of the crown. Higher proline levels in less infested species were identified. Water content imbalances due to feeding by leaf miners were most characteristic of the severely affected species. Chlorophyll fluorescence determination revealed high photochemical activity with an effective defense system in resistant species, while non-resistant species exhibited weak defense mechanisms in both sunlight and shade. To assess horse chestnut species the hyperspectral analysis indices (DSWI and SIPI) were also successfully applied. Changes in chl a and chl b content, proline levels, and leaf water-holding properties can be used to assess the resistance of horse chestnut species using classical physiological and biochemical methods. Hyperspectral analysis indices (DSWI and SIPI) can also be successfully applied.