Post-harvest dispersal dynamics of the false chinch bug, <i>Nysius cymoides</i> (Hemiptera: Lygaeidae) in a canola agroecosystem: a spatial analysis approach

Abstract The false chinch bug, Nysius cymoides (Spinola), is a polyphagous pest causing significant damage in canola ( Brassica napus L.) fields in Iran. This preliminary study aimed to investigate the dispersal pattern of N. cymoides after canola harvest to support integrated pest management strategies. Sampling was conducted using pitfall traps arranged along transects spaced approximately 60 m apart over an area exceeding 28 hectares. Insect distribution over time was mapped using ArcGIS and kriging interpolation. Results showed that N. cymoides nymphs and adults remained mainly concentrated within the harvested canola field for over 2 months post-harvest, indicating limited dispersal to surrounding fields. Nymphs exhibited broader spatial dispersion than adults, which tended to stay within the harvested area. These findings highlight the importance of post-harvest ground management practices, such as plant residue removal and ploughing, to reduce N. cymoides populations and mitigate pest pressure in subsequent canola crops.