Biological control of invasive swallow-wort plants (Vincetoxicum spp.): evaluating field releases of Hypena opulenta moths

Jake Wilson


Hypena opulenta is a classical biological control agent for swallow-worts (Vincetoxicum spp.), perennial invasive species in North America. Adult moths were released into field cages at six sites across southern New England in June and July of 2020. An additional five sites from previous years’ releases were monitored for evidence of H. opulenta establishment. All six 2020 releases showed successful larval development and 75-100% leaf damage to swallow-wort within the field cages. Only one of the five sites from previous years showed evidence of H. opulenta overwintering, but reproduction and establishment hasn’t yet been confirmed at this site.  Research on the photoperiod that initiates diapause induction of H. opulenta larvae indicates that the longest photoperiod of the summer may not be long enough in our area to allow for a second generation of this species.  Further research is necessary to identify other factors that may affect H. opulenta establishment in the field, including predation, disease, dispersal distance, and temperature-dependent development.