Insects have fundamental roles in the world, helping to maintain ecosystem functioning and stability. However, a minority of insects are pests and significantly threaten biodiversity, natural resources, and food security. World trade has increased the spread of invasive insects, and combined with increased abiotic stresses due to climate change, global agricultural, forestry, and horticultural production is under immense pressure. To counteract the threat of these pests and support the development of integrated pest management strategies, biosurveillance strategies are being employed. Biosurveillance strategies aim to collect and understand information about pest ecology and evolution and support integrated pest management by answering fundamental questions on pest origin, behavior, and movement potential. Genomic biosurveillance, leveraging high-throughput sequencing and reduced-representation sequencing (RRS) techniques, can be used to identify patterns and processes involved in movement and adaptation of insects, which is not possible to capture with traditionally used techniques (e.g., trapping). Reduced-representation sequencing methods have gained popularity due to their technical flexibility, relatively low cost, and ability to produce genome-wide data without prior knowledge of specific genomes. This chapter provides an overview of RRS methodology and its applications in insect population genetics, focusing on its potential for insect pest management in forestry, horticulture, and agroecosystems.