Delaware (elm cultivar)

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The American Elm U. americana cultivar Delaware was originally selected (as tree number 218) from 35,000 seedlings inoculated with the Dutch elm disease causal fungus in USDA trials at Morristown, New Jersey. Further trials were conducted by both the USDA and the U. S. National Arboretum, which confirmed the clone had a high level of resistance to the disease. Although propagated for further trials, the tree was never commercially released. Like all other American Elm cultivars, Delaware is susceptible to elm yellows but resistant to elm leaf beetle.

[edit] References

• • Townsend, A. M., Bentz, S. E., and Douglass L. W. (2005). Evaluation of 19 American Elm Clones for Tolerance to Dutch Elm Disease. Journal of Environmental Horticulture, March 2005, Horticultural Research Institute, Washington, D.C.