Releasing Biological Controls

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

Identifying Hypena opulenta

Hypena opulenta adults are one cm long with a wingspan of about 3cm. They have dull, light brown forewings with a dark band in the middle and hindwings that are pale orange. 

The larvae start out white, but later become green with black spots and a yellow head. 

The life cycle of Hypena starts with the emergence from the egg as a larva.  This larva goes through five stages or instars. The last molt occurs at the end of the 5th instar and transforms the larva into a pupa.  Metamorphosis occurs inside the pupa and results in the emergence of an adult winged moth. 

Adult Hypena opulenta lay between 600 to 400 eggs during an average 2-3 week lifespan.  Two generations may occur in the same year. The larvae feed exclusively on pale and black swallowwort and this was the reason that they were selected as a biocontrol.

Photos from the field

Hypena opulenta pupae being readied for release.

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

One of four 6’x6’x6’ research cages.

Adult Hypena opulenta emerged from pupae. 

Cage Monitoring Stats & Reports

2021 Field Season Overview

2020 Field Season Overview

The Eastern Lake Ontario Swallow-wort Collaborative (ELOSC), is a platform for sharing the most up-to-date research and best management practices to inform stakeholders about the prevention and management of invasive swallow-wort.

Learn More About Swallow-wort

Biocontrol Webinar Recordings

Hosted by the Eastern Lake Ontario Swallow-wort Collaborative on March 23rd, 2022. This webinar showcased swallow-wort biocontrol research that is currently underway in New York state and beyond.
Researchers from New York, Rhode Island, and Michigan provided an overview of their research, along with the results of an ongoing Hypena opulenta cage monitoring project that SLELO PRISM participates in.
  • Dr. Lisa Tewksbury- University of Rhode Island Biocontrol Lab
  • Dr. Marianna Szucs- Michigan State University
  • Robert Smith-SLELO PRISM
  • Dr. Dylan Parry- SUNY ESF

Rob Williams                              rwilliams@tnc.org                     Program Director

Megan Pistolese megan.pistolese@tnc.org
Outreach and Education

Brittney Rogers brittney.rogers@tnc.org 
Aquatic Invasive Species

Robert Smith       robert.l.smith@tnc.org 
Terrestrial Invasive Species

Zachary Simek    zachary.simek@TNC.ORG     Conservation and GIS Analyst

During this time the best way to contact our team is via email.