STROBEL G. and R. GRAY. 1990. Dutch elm disease. Am. Nurseryman 171(7): 64-69.
Dutch elm disease has inestimally damaged the beauty of the urban landscape. The origin of Dutch elm disease remains a mystery. England’s C. Brasier contends that the disease come to Europe aboard the trans-Siberian railway completed during the war. Researchers have yet to find C. ulmi in Asia or uncover all of the tragic accidents leading ultimately to the fungus’s arrival in the US. In the ’70s, a research group in Montana had an idea that seemed to have some merit; to find a natural bacterium that would antagonize the Dutch elm disease fungus, C. ulmi. Certain strains of Pseudomonas syringae not only inhibited the fungus, but killed it. In 1980, the Chevron Chemical Co. of San Francisco began extensive field tests. After four years and millions of dollars, the company had little success with P. syringae. Holland’s R. J. Scheffer discovered that the bacterium treatment could be effective. He treated 7,000 European elms suitably sized for street tree use, leaving an equal number of untreated as the control. The treated population consistently contained significantly fewer diseased trees than the control group. Dr. C. W. Murdock of the University of Maine, Orono, has extensively tested natural strains of P. syringae in some of New England’s American elms. His results are similar to Scheffer’s.
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