Overseas immigration of fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae), invading Korea and Japan in 2019

Abstract

The fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith), spread rapidly in Africa and Asia recently, causing huge economic losses in crop production. Fall armyworm caterpillars were first detected in South Korea and Japan in June 2019. Here, the migration timing and path for FAW into the countries were estimated by a trajectory simulation approach implementing the insect's flight behavior. The result showed that FAWs found in both South Korea and Japan were estimated to have come from eastern China by crossing the Yellow Sea or the East China Sea in 10–36 h in three series of migrations. In the first series, FAW moths that arrived on Jeju Island during 22–24 May were estimated to be from Zhejiang, Anhui and Fujian Provinces after 1–2 nights’ flights. In the second series, it was estimated that FAW moths landed in southern Korea and Kyushu region of Japan simultaneously or successively during 5–9 June, and these moths mostly came from Guangdong and Fujian Provinces. The FAW moths in the third series were estimated to have immigrated from Taiwan Province onto Okinawa Islands during 19–24 June. During these migrations, southwesterly low‐level jets extending from eastern China to southern Korea and/or Japan were observed in the northwestern periphery of the western Pacific Subtropical High. These results, for the first time, suggested that the overseas FAW immigrants invading Korea and Japan came from eastern and southern China. This study is helpful for future monitoring, early warning and the source control of this pest in the two countries.

Flight Capability and the Low Temperature Threshold of a Chinese Field Population of the Fall Armyworm Spodoptera frugiperda

“…This may mean that layers of migrating S. frugiperda may form at similar altitudes to that of migrant H. armigera . Previously, the developmental threshold temperature of 13.8 °C was adopted as the flight low temperature threshold in the trajectory simulation in our previous studies [ 3 , 7 , 8 , 9 , 33 ]. As 13.8 °C is rather similar to the flight low temperature threshold of 13.1 °C quantified in this study under a declining temperature treatment, the migration distance and the distribution of S. frugiperda predicted in previous studies can be considered reliable [ 3 , 7 , 8 , 9 , 33 ].…”

“…However, due to its migratory capability, adults re-invade these areas each spring or summer by migrating from winter-breeding regions [ 6 ]. For example, S. frugiperda has already formed a seasonal migration pattern in East Asia, migrating from its year-around breeding area in the Indochina Peninsula and South China as far as Northeast China, Japan and the Korean Peninsula [ 3 , 7 , 8 , 9 ]. Therefore, it is important to evaluate the flight capability of S. frugiperda for accurate monitoring and prediction of the range and timing of its migration, so as to effectively control this migrtory pest and reduce the application of pesticides.…”

Safety Evaluation of Chemical Insecticides to Tetrastichus howardi (Hymenoptera: Eulophidae), a Pupal Parasitoid of Spodoptera frugiperda (Lepidoptera: Noctuidae) Using Three Exposure Routes

“…For T. howardi , the toxicity of six insecticides was determined using the glass vial method [ 24 ] on its newly emerged adults (1 d old, no distinction between male and female). Preliminary experiments were performed starting from the recommended field application rate with a set of decreasing serial dilutions to determine the range of insecticide concentrations [ 14 ]. The recommended field rate was obtained from the Electronic Pesticide Manual of ICA, MOA, China ( (accessed on 22 October 2021)).…”

“…As a case in point, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), a worldwide invasive pest that originated from Tropical America [ 11 ], with a wide range of plant feeding and a high migratory capacity, this species has spread rapidly worldwide, causing substantial economic losses [ 12 , 13 , 14 ]. The S. frugiperda continued to spread and was detected in China in January 2019 [ 15 ].…”

The Source Areas and Migratory Pathways of the Fall Armyworm Spodoptera frugiperda (Smith) in Sichuan Province, China

“…The simulation of this platform has been proven to have a high accuracy by the mark-recapture experiment of rice planthoppers [ 29 ]. Backward trajectories were simulated based on the following FAW flight characteristics and parameters: (1) FAWs fly downwind [ 30 , 31 ]; (2) FAWs mostly fly for three consecutive nights [ 11 ]; (3) FAWs fly at night, taking off at dusk and landing on the following dawn [ 32 ], and FAWs can fly continuously for 10 h every night [ 33 , 34 ]. According to the sunrise and sunset data in Sichuan, the takeoff time was set to 20:00 Beijing time (12:00 UTC), and the landing time was set to 6:00 Beijing time (22:00 UTC).…”