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Simple Summary: The invasive pest Spodoptera frugiperda has become a global problem. Sterile insect technology is an effective means to prevent invasive insects, but at present, the research on this pest is not perfect. Our results showed that egg sterility in offspring reached 74% when the ratio of those given a 250 Gy dose of X-ray radiation to the non-irradiated males was 12:1, and there was no significant difference in mating competitiveness between irradiated males of different ages. Additional cornfield cage studies confirmed this finding by showing that release ratios from 12:1 to 20:1 significantly reduced larval populations in the field, with a 48 to 69% leaf protection effect and a 58 to 83% insect population reduction. This study provides fundamental information for the management of S. frugiperda through the use of sterile insect techniques. Spodoptera frugiperda, an invasive pest, has a huge impact on food production in Asia and Africa. The potential and advantages of sterile insect techniques for the permanent control of S. frugiperda have been demonstrated, but the methods for their field application are still unavailable. For the purposes of this study, male pupae of S. frugiperda were irradiated with an X-ray dose of 250 Gy to examine the effects of both the release ratio and the age of the irradiated males on the sterility of their offspring. The control effect of the irradiated male release ratio on S. frugiperda was evaluated using field-cage experiments in a cornfield. The results showed that when the ratio of irradiated males to non-irradiated males reached 12:1, the egg-hatching rate of the offspring of S. frugiperda decreased to less than 26%, and there was also no significant difference in mating competitiveness among the different ages. Field-cage testing showed that when irradiated males were released at ratios of 12:1–20:1 to normal males, the leaf protection effect for the corn reached 48–69% and the reduction in the insect population reached 58–83%. In this study, an appropriate release ratio is suggested, and the mating competitiveness of irradiated and non-irradiated males of S. frugiperda is investigated, thus providing a theoretical basis for the use of sterile insect techniques to control S. frugiperda. [ABSTRACT FROM AUTHOR]

The fall armyworm (FAW), native to the Americas, has rapidly invaded the whole of Southern China since January 2019. In addition, it can survive and breed in the key maize- and rice- growing area of the Yangtze River Valley. Furthermore, this pest is also likely to continue infiltrating other cropping regions in China, where food security is facing a severe threat. To understand the potential infestation area of newly-invaded FAW from the Yangtze River Valley, we simulated and predicted the possible flight pathways and range of the populations using a numerical trajectory modelling method combining meteorological data and self-powered flight behavior parameters of FAW. Our results indicate that the emigration of the first and second generations of newly-invaded FAW initiating from the Yangtze River Valley started on 20 May 2019 and ended on 30 July 2019. The spread of migratory FAW benefitted from transport on the southerly summer monsoon so that FAW emigrants from the Yangtze River Valley can reach northern China. The maize-cropping areas of Northeastern China, the Korean Peninsula and Japan are at a high risk. This study provides a basis for early warning and a broad picture of FAW migration from the Yangtze River Valley. [ABSTRACT FROM AUTHOR]