ABSTRACT.- South American invasive plants in the genus Ludwigia (Onagraceae) degrade many riparian and aquatic ecosystems worldwide. Biological control may aid in the management of these exotic weeds, but data on the host specificity of Ludwigia natural enemies is limited. The biology and host range of Sudauleutes bosqi Hustache (Coleoptera: Curculionidae), an herbivore of Ludwigia spp. in South America, was studied to determine its suitability as a biological control agent for 3 exotic Ludwigia spp. (targets) in the US. © 2022 Florida Entomological Society. All rights reserved.