Help requested: Look for and report diseased buckthorn

Forwarding a request from Laura Van Riper, MN DNR’s Terrestrial Invasive Species Coordinator.  A ray of hope for buckthorn control!?


As you are out and about this summer, could you keep a lookout for common/European buckthorn trees with witches’ broom/yellows disease symptoms?  Research to identify biocontrol insects for buckthorn has been on-going since 2001. A phytoplasma disease was detected in potential biocontrol insects and Rhamnus species in Europe. It has not been reported in the US. We need to know if this phytoplasma is already present in North America. We need your help! See attached PDF flyer for details and photos. Reports can be directed to Dr. Roger Becker of the University of Minnesota (
Thank you!


The University of Minnesota Extension Forestry team.

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  1. I’m in the thick of work battling several acres of buckthorn on my land. I’ve noticed that under the shade of Black Walnut trees the buckthorn is absent. Has anyone investigated the possibility of exploiting the alleopathic agent for buckthorn control?

    1. Hi Merle. I’m not aware of anybody exploring the use of black walnut’s allelopathic properties, or the chemicals that cause them, for buckthorn control. One challenge with that approach is that eliminating the buckthorn is only half (or less) of the problem: The challenge remains of revegetating the site with natives. Allelopathic chemicals would inhibit establishment or growth not only of buckthorn, but also of many native potential replacement species (except, of course, for itself). That would make it hard to restore a native post-buckthorn system.