Specialisation Matters: Landscape Structure Shapes the Distribution of Plutella xylostella and Its Parasitoids

Landscape heterogeneity is a key driver of ecological processes, shaping dispersal, biodiversity, and ecosystem services. In agricultural systems, landscape structure regulates pests by influencing herbivores and their natural enemies. Plutella xylostella , a major pest of Brassicaceae, causes severe economic losses and is difficult to control due to insecticide resistance and reduced natural enemy effectiveness. In Córdoba, Argentina, its main parasitoids are Diadegma leontiniae and Siphona sp. We hypothesised that larger, more connected patches of host plants (Brassica crops) would increase pest and parasitoid abundance, while greater area of non‐host vegetation would suppress the pest but benefit natural enemies. From September to December in 2021, 2022, and 2023 (spring season), we conducted surveys of P. xylostella larvae and pupae every 2 weeks in 29 brassica plots across the horticultural area of Córdoba. Specimens were reared under controlled conditions until adults or parasitoids emerged. Landscape structure within 200 m of each plot was quantified using GPS, Google Earth, and Sentinel‐2 imagery. Four landscape metrics were estimated: Mean Brassica Plots Area (MAREA), Total Brassica Area (CA), Connectivity (MPROX), and Mean Non‐Host Area (MNHAREA). We used generalised linear models and generalised linear mixed models, with model selection based on AIC and multimodel inference. Results showed that P. xylostella abundance increased with MAREA and declined with higher connectivity (MPROX), whereas MNHAREA and CA had little effect. Parasitism rates of D. leontiniae exhibited similar associations, while those of Siphona sp. decreased with increasing MAREA and MNHAREA. Overall, patch size, distribution, and connectivity strongly influenced pests and parasitoids but in contrasting ways. Incorporating such scale‐dependent responses into integrated pest management is crucial for sustainable regulation of P. xylostella in diversified agricultural systems.