Two swallow-wort species (Vincetoxicum nigrum and V. rossicum) of European origin have become widespread and abundant in northeastern North America, threatening natural areas by displacing native plant species and altering ecological processes. In addition, swallow-worts are a nuisance to homeowners and are increasingly becoming a concern in agricultural settings, particularly pastures. In 2006, we located several European swallow-wort populations to collect and begin evaluating potential biocontrol agents. Due to the relatively well-known herbivore complex of the congener species V. hirundinaria, this plant was also included in the survey. Over the past year, feeding trials were initiated with five promising candidates representing three feeding guilds (seeds, leaves, and roots) against three Vincetoxicum spp. and with closely related plants native to North America. This system is unique because we are evaluating insect agents against two species within the same genus whose distributions are not overlapping in Europe, but are currently or will likely be sympatric in some areas of North America. In addition, we are evaluating agents for release against Vincetoxicum spp. that are not known to be natural hosts in Europe. This presentation will focus on patterns of host use by these herbivores within the genus Vincetoxicum and address their potential effectiveness as biocontrol agents of swallow-worts in North America.