The fall armyworm, Spodoptera frugiperda (Smith, 1797), originated from tropical and subtropical America is one of sporadic agricultural pests in the world. Since the moth has high migration capacity, it rapidly expanded the world distribution such as Africa in 2016, India in 2018, and East-Asian countries in 2019. In Korea, this species was firstly found at maize fields of Jeju Island, in early June 2019, and subsequently detected at many counties of Jeolla-do and Gyeongsang-do in June and July 2019. The first invaded populations of S. frugiperda in Korea were genetically confirmed as one species, S. frugiperda by using a mitochondrial cytochrome oxidase subunit I (COI) gene, and analyzed to be comprised of two haplotypes (hap-1 and hap-2) each belonging to different clades. Among 31 COI sequences, the hap-1 sequence was predominant, accounting for 93.5%.

The recent increase in agricultural commodities from abroad and travelers due to the economic growth and globalization in Korea has resulted in an increase in invasive alien insect species establishing in Korea. When “alien” is defined as species introduced after the beginning of the Greater Korean Empire Era (1897), 171 insect species are considered invasive alien species. On average, 0.85 alien insect species have become established each year for the last 40years, and 76.6% of the alien insect species are economic agricultural pests. The annual invasion rate and the pest interceptions from imported cut flowers, planting material, and vegetables have been increasing rapidly. Traveler's baggage is an important pathway for fruit flies. Most of the alien pests that were first found in Japan were confirmed in Korea at least 3years later until the 1990s, but the pattern has been reversed since the 2000s. Thus, continuous information sharing with neighboring countries such as Japan and China is needed to develop a system for early detection and prompt action against invading insect species. Thus, we introduce and summarize the present status of invasive alien insect species in Korea.