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Aquatic Weed Among ‘World’s Worst’ Expands in Northeastern US

A new Weed Science Society of America research publication provides insights on how a destructive invasive aquatic weed species is spreading, and how to keep it contained.

Posted on May 7, 2024

Topped out Hydrilla at St. Clement Marina, Portland, CT 2020. For more information, see article by Foley et al. in this issue.
Photo credit: Greg Bugbee.

WESTMINSTER, Colorado – 7 May 2024 – An article in the latest issue of Invasive Plant Science and Management provides new insights on a northern hydrilla (Hydrilla verticillata) subspecies (lithuanica) and its establishment outside the Connecticut River. Considered among the “world’s worst” aquatic weeds, northern hydrilla hinders recreational activities by forming dense canopies. If unchecked, it has the potential to displace native species and host a bacterium that produces a neuro toxin implicated in bald eagle and waterfowl deaths.

“The spread and establishment of yet another hydrilla subspecies in the United States is alarming,” says Jeremiah Foley, an assistant agricultural scientist with the Connecticut Agricultural Experiment Station, and lead author for the study. “Especially alarming is the negative impacts that this invasive aquatic weed can have on native aquatic and non-aquatic plant and animal species, and how quickly it’s spreading.”

Until 2022, this subspecies had remained undocumented outside the Connecticut River.  However, by the end of 2023, researchers had documented its presence in five additional Connecticut waterbodies and one in Massachusetts.

Click here to read the full article.