Our Invasive Species Program via SLELO PRISM recently partnered with multiple agencies to release a second
round of insects for targeted suppression of one of New York’s most aggressive terrestrial invasive species –
pale swallow-wort (Cynanchum rossicum). Dozens of moth pupae known as Hypena opulenta were released in
four sites along Eastern Lake Ontario and along the St. Lawrence River – the epicenter of swallowwort in
North America.

Native to Ukraine, swallowwort was likely introduced to North America as an ornamental plant, soon
spreading to several northeastern states. The plant creates extremely dense monocultures spreading over
acres upon acres of otherwise biologically diverse natural systems. The biological control, Hypena opulenta, is
also from the Ukraine and feeds exclusively on swallowwort.

Partnering with the NYS Invasive Species Research Institute, the Thousand Islands Land Trust, SUNY ESF,
University of Rhode Island, the USDA Agricultural Research Service and local volunteers, our SLELO PRISM
assisted with caged releases of Hypena opulenta at four sites within the Eastern Lake Ontario and St. Lawrence
Region. This important work will help to restore Priority Conservation Areas (PCA’s) to their natural ecological

Hypena opulenta pupae being readied for release.

One of four 6’x6’x6’ research cages.

Pupae remain in the release bucket until they
mature into egg-laying adults inside the screened

This year many egg-laying adult moths
emerged = success!

Of the three release sites, Hypena opulenta are the most successful at defoliating invasvie swallow-worts in cages located at the Whele Forest.