Issue 13, July 30, 2010

Japanese Beetle Resistant Elms

Research published in May, 2010 by Jennie M. Condra, Christina M. Brady, and Daniel A. Potter of the University of Kentucky provides Japanese beetle resistance information for Dutch elm disease resistant elms. They found that the Japanese elm species Ulmus parvifolia and U. propinqua and their cultivars were less susceptible to feeding by adult Japanese beetles than American elm, U. Americana, native to North America and U. wilsoniana, native to China. In general, hybrid elms were more heavily defoliated than the straight species. Of the hybrids tested, New Horizon and Frontier consistently experienced less feeding damage, whereas Morton Glossy Triumph suffered heavy damage. All three hybrids have some Japanese species heritage, so the Japanese species resistance is not a major factor in all hybrids. The research article, Resistance of Landscape-Suitable Elms to Japanese Beetle, Gall Aphids, and Leaf Miners, with Notes on Life History of Orchestes alni and Agromyza aristata in Kentucky, was published in Arboriculture and Urban Forestry 36(3): 101-109. Information is also provided on European flea weevil and a leaf mining fly.--Phil Nixon

Phil Nixon

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