Thursday, August 20, 2020

Biological Control for Japanese Knotweed tested in New York

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.

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

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7 Responses

  1. Christine hildebrand says:

    Thank you for keeping us informed. Hopefully this will work and these introduced insects will not harm native plants as well controlling Japanese Knotweed which we all need.

  2. Jeep says:

    Diesel fuel sprayed works real well. Works great on burdock too!

  3. Dick says:

    Diesel Fuel?? Not a good idea for frogs etc. The run-off would pollute the streams, rivers and lakes. Dick

  4. Smitty says:

    Oh great! Introduce a non-native spieces to eliminate another non-native spieces, that always turns out well!!

  5. Jeep says:

    Dick, we’re not talking a 55 gallon drum of the stuff! Just enough to get the job done. Works great!

  6. David Bower says:

    I would be VERY CAREFUL about importing ANOTHER foreign species in the effort to control something. This has been tried in a number of places, and often the 2nd species finds something new to eat that it likes even better than the original intended prey, and now you have TWO out-of-control invasive species. These unintended consequences just through the ecosystem even more out of balance.

  7. Justine McClellan says:

    The article fails to mention that they have been using Alphalora itadori to control knotweed successfully for 10 years and it has been extensively studied with no harmful side effects to date.

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