Defoliation Impact of Apocheima Cinerarius (Geometridae) on Desert Poplar (Populus Euphratica) Populations in the Zarafshan National Park

Desert poplar (Populus euphratica) is a key tree species in riparian ecosystems, significantly contributing to ecological stability, biodiversity conservation, and the protection of desert landscapes in Central Asia.However, natural populations and vegetation, including those in the Zarafshan National Park, Samarkand, Uzbekistan, have gained increasing effects from defoliating insect pests, especially Apocheima cinerarius, which belongs to the family Geometridae and order Lepidoptera.The larvae feed actively on poplar leaves, causing severe defoliation during outbreak periods.Defoliation reduces photosynthetic capacity, weakens tree vitality, and increases vulnerability to environmental stress conditions.Recurring foliage damage may result in reduced growth, crown thinning, and limited natural regeneration, ultimately disrupting the ecological balance of arid riparian forests.Field surveys conducted from 2021 to 2025 across riparian lowlands, river terraces, and semi-arid zones, revealed clear spatial and seasonal variations in larval density and foliage damage.Larval abundance peaked in late spring and early summer, with the highest defoliation observed in lowland forests, while semi-arid zones experienced less damage.A significant (p < 0.05) correlation between larval density and defoliation (r = 0.62) highlighted the important role of population size in leaf loss.This study provides field-based insights into population dynamics and supports the strategies in sustainable pest management.