Adaptive strategies of Aesculus against Cameraria ohridella: implications for urban green space management

The horse-chestnut leaf miner ( Cameraria ohridella Deschka & Dimič) is one of the most destructive invasive pests of horse-chestnut ( Aesculus hippocastanum L.), causing widespread damage to urban trees throughout Europe and reducing essential ecosystem services, including carbon sequestration, evapotranspiration, and microclimate regulation. Although numerous studies have investigated the biology, invasion dynamics, and control of C. ohridella , an integrative understanding of host physiological responses and their implications for sustainable urban management remains lacking. The principal aim of this review is to develop an integrative understanding of the host–herbivore–urban environment system by synthesizing current knowledge from plant physiology, biochemistry, ecology, and urban forestry. The review synthesizes current evidence on the structural, physiological, biochemical, and ecological responses of Aesculus species to C. ohridella infestation, including alterations in leaf anatomy, photosynthesis, transpiration, oxidative metabolism, volatile organic compound (VOC)-mediated signaling, phenology, and interactions with phytopathogens and environmental stressors. We further evaluate interspecific variation in susceptibility among Aesculus species, identify anatomical and biochemical traits associated with resistance, and critically examine how urban microclimate, landscape structure, and climate-related factors influence pest development and infestation severity. By integrating these diverse lines of evidence, the review provides a system-level understanding of the interactions among Aesculus species, C. ohridella , and the urban environment. It also critically evaluates current urban management approaches, including sanitation measures, biodiversity-based strategies, biological control, and the selection of resistant taxa for sustainable urban planting. This integrative synthesis provides a scientific foundation for understanding host resistance, predicting pest dynamics, identifying resistance-associated traits, and developing sustainable strategies to enhance the resilience of urban tree populations under increasing biotic and climatic pressures.