Japanese 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.
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.