【目的】 报道我国新的重要外来入侵害虫——刺槐突瓣细蛾Chrysaster ostensackenella (Fitch, 1859)和同属的圣突瓣细蛾C. hagicola Kumata, 1961的生物学。【方法】 害虫的危害情况和生物学等均在发生地区进行观察和研究。【结果】 首次发现原产北美的刺槐突瓣细蛾入侵我国境内（山东和辽宁），严重危害刺槐。这是该害虫在原产地以外的唯一记录。在山东烟台的一些地区，刺槐突瓣细蛾一年发生4代，刺槐小叶被害率达80%以上，成片树木叶片枯焦，引起树叶早落，严重影响树木光合作用，导致树木营养不良，生长受到很大影响；在发生严重的林片，有虫株率达100%，小叶被害率达90%以上。同时首次报道同属的圣突瓣细蛾在中国的分布和为害情况。为了便于监测结果的准确鉴定，文中给出了两种害虫的形态和鉴别特征。【结论】 突瓣细蛾属Chrysaster Kumata, 1961仅有的两个种在我国同时被发现，其中刺槐突瓣细蛾对我国刺槐构成重大威胁，需要引起相关造林绿化和植物检疫部门的重视。

 [Objectives]  To report the biology of a new, economically important, invasive pest of the black locust Robinia pseudoacacia L, Chrysaster ostensackenella (Fitch, 1859), and a congeneric species, C. hagicola Kumata, 1961 of the family Gracillariidae in China. [Methods]  The damage on leaves of the black locust and the biology of these pests were studied in the field. [Results]  Chrysaster ostensackenella was recorded for the first time in China in Shandong and Liaoning Provinces. The record reported here is the only validated record of this species outside its native North American range. In Yantai, Shandong Province, C. ostensackenella had four generations a year and attacked more than 80% of the leaflets of black locust trees, resulting in an accelerated abscission of leaves. In some of the more seriously infested stands, all trees, and more than 90% of leaflets were damaged. In addition, a congeneric species, C. hagicola, was newly recorded in China, and its biology studied. Morphological and diagnostic characters of the two pests are provided to assist precise identification and biological monitoring. [Conclusion]  Both species of the genus Chrysaster Kumata are found in China, of which C. ostensackenella is an invasive pest that seriously threatens the black locust, R. pseudoacacia. Relevant control measures should be undertaken by afforestation and plant quarantine departments and intensive studies conducted to fully understand this invasive species.