Nearly 40 different Asian elm (Ulmus spp.) biotypes, growing at The Morton Arboretum, Lisle, IL, were evaluated in laboratory bioassays and in the field for suitability and feeding preference of the spring cankerworm Paleacrita vernata (Peck) and the fall cankerworm, Alsophila pometaria (Harris). No-choice and multiple-choice laboratory feeding studies, and field defoliation surveys revealed that U. castaneifolia, U. changii, U. chenmoui, U. davidiana, U. elongata, U. gaussenii, U. glaucescens var. lasiophylla, U. japonica, U. lamellosa, U. lanceaefolia, U. macrocarpa, U. parvifolia, U. propinqua, U. propinqua var. suberosa, U. prunifolia, U. pseudopropinqua, U. taihangshanensis, U. wallichiana, U. wilsoniana, U. wilsoniana-98, and the simple and complex hybrids U. davidiana x U. japonica, U. davidiana x U. propinqua, U. japonica x U. ‘Morton’-Accolade, U. ‘Morton’-Accolade x U. japonicapumila, U. ‘Morton Glossy’-Triumph, and U. ‘Morton Plainsman’-Vanguard x U. davidiana, were less suitable for larval development and pupation and less preferred by spring and fall cankerworm larvae. Ulmus americana, U. glaucescens, U. szechuanica, and the simple and complex hybrids U. davidiana x U. ‘Morton’-Accolade, U. szechuanica x U. japonica, U. ‘Morton’-Accolade, U. ‘Morton Red Tip’-Danada Charm and U. ‘Morton Plainsman’-Vanguard were more suitable for and more preferred by spring and fall cankerworm larvae. Rankings for larval development time were highly correlated with larval longevity, but the proportion of larvae pupating was correlated neither with larval longevity nor with larval development time. Pupal fresh weights also were correlated neither with larval longevity nor with larval development time. Mean fecal pellet weights were correlated with the proportion of larvae pupating, but were not correlated with pupal fresh weights. Ulmus chenmoui, U. glaucescens var. lasiophylla, U. lamellosa, U. macrocarpa, U. propinqua, U. prunifolia, and U. pseudopropinqua all showed medium to heavy leaf pubescence and were less suitable and less preferred by spring and fall cankerworms. Asian elms were least preferred by cankerworm larvae, followed in order of increasing preference by European and North American elms.

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Author notes

We thank M.E. Dix, USDA Forest Service, Washington, DC, for her helpful review of an earlier draft of the manuscript; and J. Jackson, K. Ludwig, A. Merritt, and M. Miller for their assistance with laboratory bioassays, field defoliation surveys, data entry, and manuscript preparation.

2Professor of Horticulture and Research Associate, Entomology, The Morton Arboretum, 4100 Illinois Route 53, Lisle, IL 60532.

3Research Assistant and Research Associate, Dendrology, respectively, The Morton Arboretum, 4100 Illinois Route 53, Lisle, IL 60532.