Distance-Dependent Patterns of Metcalfa pruinosa (Say, 1830) Across a Forest–Crop Interface in an Agricultural Landscape

Invasive polyphagous insects are an increasing concern in agricultural landscapes, particularly where forest and crop habitats occur in close proximity. The invasive planthopper Metcalfa pruinosa (Say, 1830) has expanded widely across Europe, yet its distribution across forest–crop interfaces remain insufficiently documented. This study examined the population dynamics of M. pruinosa along a forest–crop gradient in western Romania during the 2024–2025 growing seasons. Monitoring was conducted in a deciduous forest habitat and in adjacent crop systems located at increasing distances from the forest edge. In the forest habitat, adult abundance was consistently higher near the forest margin, while nymphs were recorded in the forest interior, indicating local development. In adjacent crop systems, both adult and nymph abundance showed a clear distance-dependent decline, with higher values recorded closer to the forest edge. Crop-level incidence and seasonal severity generally followed the same spatial pattern, with higher infestation levels in sites located nearer to the forest margin. These findings show a consistent spatial association between forest proximity and variation in M. pruinosa abundance and infestation levels across the forest–crop interface.