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Trials with the American elm have been successful; in a six-year experiment with the American elm in Denver, CO, annual Dutch elm disease losses declined significantly after the first year from 7 percent to between 0.4 and 0.6 percent; [48] a greater and more rapid reduction in disease incidence than the accompanying tree sanitation and plant ...
Dutch elm disease (DED) is a fungal disease that has ravaged the American elm, causing catastrophic die-offs in cities across the range. It has been estimated that only approximately 1 in 100,000 American elm trees is DED-tolerant, most known survivors simply having escaped exposure to the disease. [19]
The American Elm cultivar Ulmus americana 'Valley Forge' was raised by the Agricultural Research Service in Maryland. The tree was released to wholesale nurseries without patent restrictions by the U. S. National Arboretum in 1995 after proving to have a high resistance to Dutch elm disease. 'Valley Forge' proved only moderately successful in ...
The tree remains common across the Prairie Provinces (Alberta is free of Dutch elm disease and other malaises typical of the American Elm). 'Brandon' also remains in cultivation in the city of Bozeman , Montana , where it is prized as an amenity tree by the Forestry Division, [ 10 ] and in California .
Testing in laboratory conditions by the United States Department of Agriculture from 1992 to 1993 revealed that 'Princeton' had some resistance to Dutch elm disease (DED), [6] [7] [8] although the original Princeton elm, which grew in Princeton Cemetery and was estimated to be over 150 years old, was felled in April 2005 after suffering 60 percent dieback, attributed by some accounts to Dutch ...
The American Elm cultivar Ulmus americana 'Delaware' was originally selected (as tree number 218, a c.1940 seedling from North Dakota) from 35,000 seedlings inoculated with the Dutch elm disease fungus in USDA trials at Morristown, New Jersey. [1]
Dutch elm disease is a pathogen spread by beetles that devastated American elm, other native elms are more resistant; Thousand cankers disease is a fungus carried by a beetle that infests black walnut; Oak wilt is a fungal pathogen spread by sap beetles that infects oaks; Beech bark disease is a fungus carried by a scale insect that infests ...
The American Elm cultivar Ulmus americana 'Jefferson' was cloned from a tree growing near a path in front of the Freer Gallery of Art, close to the Smithsonian Institution Building ("The Castle") on the National Mall in Washington, D.C. [1] The United States National Park Service, which had planted the tree during the 1930s, cloned it in 1993 after screening tests showed that it possessed an ...