Bio Control for Knotweed

Let’s hope this new “bio control” method proves successful!

Biological Control for Japanese Knotweed Released in New York

A man with a bag in a patch of knotweedJapanese knotweeds (Reynoutria japonica, Reynoutria sachalinensis, and their hybrid Reynoutria X bohemica) are invasive plants that are infamously difficult to control and have negatively impacted ecosystems and economies in the US, Canada and Europe. For several years, researchers have sought to find a biocontrol for knotweed. Biocontrols are species selected from an invasive species’ native range that are used to control the invasive species in its introduced range. This approach is more targeted than chemical methods, and when successful, it permanently suppresses the invasive species. Now, after several years of biocontrol research for knotweeds, there may be some good news on the horizon. 

After extensive testing and review by federal agencies, in March of this year, an insect native to Japan called the knotweed psyllid (Aphalara itadori) was approved for release in the United States as the country’s first biocontrol agent for Japanese knotweed. This sap-sucking insect was released in New York State on June 10 by Dr. Bernd Blossey and colleagues from Cornell University. A week after releasing the 2,000 A. itadori adults at two locations in Tioga and Broome counties, the researchers found the insects had successfully laid eggs. The releases in NY are part of a nationwide effort with similar releases made in Rhode Island, Massachusetts, West Virginia, North Carolina, Oregon, and Washington State.

The Blossey Lab remains cautiously hopeful for success of A. itadori releases, however they will continue to explore additional safe, effective biocontrol organisms from Japan and China. This work in NY is led by Dr. Bernd Blossey in collaboration with the NY Invasive Species Research Institute, with funding from the Environmental Protection Fund as administered by DEC.

Photo of biocontrol release provided by Dr. Stacy Endriss