Abstract:  The fall armyworm (FAW), Spodoptera frugiperda, was originally distributed in America and is able to migrate over a long distance. It spread to Europe in 1988 and Africa in 2016, and caused huge loss to grains. It first invaded Asia in 2018, and then invaded China from Myanmar in 2019 and has been rapidly distributed in a dozen provinces in China. According to its specific hosts and molecular markers, FAW can be classified into two host-specific strains, the corn strain and the rice strain. (Z)-9-tetradecen-1-ol acetate was identified as a sex pheromone component of FAW in 1967 for the first time. Up to 1986, the blend of (Z)-9-tetradecen-1-ol acetate and (Z)-7-dodecen-1-ol acetate at a ratio of 96.6∶3.4 showed the strongest attractiveness to FAW, and was used to monitor the population dynamics of FAW broadly. In addition, (Z)-11-hexadecen-1-ol acetate, (Z)-9-dodecen-l-ol acetate and (E)-7-dodecenyl acetate in the pheromone gland extracts of female adults of FAW were reported to contribute to attracting males in different geographic regions. Both the strains are morphologically indistinguishable and share the same gland extract components, but have strain-specific ratios of pheromone components. The two strains can be hybridized in the laboratory, and the pheromone component ratio of F1 generation females is similar to that of the maternal parents. The periphery coding mechanisms to sex pheromone in FAW males are still unclear. In consideration of the occurrence of FAW in China and the progress in its sex pheromone communication, the following aspects of FAW are suggested to be investigated urgently: (1) identifying the sex pheromone of the invaded populations of FAW and using the sex pheromone for its population monitoring and control as soon as possible; (2) the olfactory coding mechanisms of males of FAW to pheromone blends; (3) the behavioral isolation between the two stains of FAW and outcomes of the hybrids.

Key words: Spodoptera frugiperda, sex pheromone, strain, hybrid, periphery coding, biocontrol