American Elm

Elm Yellows: The Re-Emergence of an Old Killer

Jim Chatfield and I visited the USDA Forest Service, Northeastern Research Station, in Delaware, OH, on Monday where they are waging a battle to eliminate Elm Yellows (EY) from their American Elm Restoration Project research plots.  I last saw the disease in southwest Ohio in 2013. 

The problem is that American elms (Ulmus americana) that are resistant to Dutch Elm Disease (DED) have no known resistance to Elm Yellows (EY).  DED is caused by a fungal infection; EY is caused by a phytoplasma which is a type of bacterium.  DED fungi plug the xylem.  The EY phytoplasma...

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Joe Boggs
Jim Chatfield