Dutch Elm and U. Americana
Name: James O.
Date: Thursday, June 06, 2002
what is it that makes the American elm, U. americana,
particularly susceptible to Dutch elm disease?
For info on Dutch elm disease:
Anthony R. Brach, Ph.D.
As the name implies, I believe that Dutch elm disease was "imported" to
North America rather recently (~last 100 yrs. ??) from Europe. As a result
the American elms had no resistance and the disease had no predators. This
happens frequently when a non-native flora/fauna are introduced into an
eco-system by some intervention (e.g. humans). Lampries, alewives,
eucalyptus trees, kudzu zu (spelling??),... the list is long of organisms
introduced into surroundings where evolution has not had time to provide a
balance of feeders/predators and a species multiplies explosively.
"Dutch elm disease is a classic example of the catastrophic devastation that
can occur when an exotic pathogen is introduced into a previously unexposed
population of trees with little or no genetic resistance."
Kansas State University extension fact sheet at
A pathogen - fungus in this case - imported from another region attacks
hosts that have not developed any resistance to it. All native American elms
are susceptible, but I could not find anything that says why American elms
is more vulnerable than slippery, rock and other native elms.
For more information see that web site or one of many others that you can
find with a Google search.
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Update: June 2012