Palatability and Suitability of the Ulmaceae for Spongy Moth Larval Development (Lepidoptera: Lymantriidae)

Abstract

Abstract Fifty-nine Ulmus taxa, varieties, and cultivars and six Zelkova taxa and cultivars were evaluated in no-choice (NC) and multiple-choice (MC) laboratory feeding bioassays for suitability and preference for spongy moth larvae (Lymantria dispar L.). Ulmus ‘Morton Stalwart’-CommendationTM, U. ‘Morton Red Tip’-Danada CharmTM, ‘Frontier’, ‘Homestead’, ‘Regal’, and U. elliptica were found to be the most suitable (suitability ratios of > 0.90). Ulmus gausennii, and U. carpinifolia were the least suitable (suitability ratio < 0.5). The remaining Ulmus and Zelkova taxa were either unsuitable (i.e. larvae failed to pupate) or were moderately suitable (suitability ratios 0.54 to 0.86). Dry frass weight was a moderate predictor of larval longevity. Feeding preference was moderately correlated with larval longevity and percent larval survival. Leaf thickness and toughness does not appear to affect larval survival, pupal fresh weight, or frass production. Asian elm leaves possess both glandular and straight trichomes but they did not affect larval suitability. Hybridization significantly affected host susceptibility and appears to contribute to an “U. pumila and U. carpinifolia factor” for host preference, susceptibility, and suitability. There appears to be a rich pool of Ulmus and Zelkova taxa for potential use in future tree breeding programs. Species used in this study: Lymantria dispar L; Malus sylvestris Mill.; Quercus palustris Munchh.; Ulmus alata Michx.; U. americana L.; U. bergmaniana C.K.Schneid.; U. carpinifolia Gled;, U. castaneifolia Hemsl.; U. chenmoui Cheng; U. crassifolia Nutt.; U. davidiana Planch.; U. elliptica K.Koch.; U. foliaceae Gilbert; U. gaussenii Cheng; U. glabra Hudson; U. glaucescens Franch.; U–. glaucescens Franch. var. lasiocarpa Rehd.; U. japonica Sarg.; U. laevis Pall.; U. lamellosa C. Wang et S.L. Chang et L.K. Fu; U. macrocarpa Hance; U. microcarpa L.K. Fu; U. multinervis (syn.U. castaneifolia) Cheng; U. parvifolia Jacq.; U. procera Salisb; U. propinqua Koidz.; Henry; U. prunifolia Cheng et L.K. Fu; U. pseudopropinqua Wang et Li; U. pumila L.; U. serotina Sarg.; U. sukaczevii Andr.; U. szechuanica Fang; U. taihangshanensis, S.Y. Wang; U. thomasii Sarg.; U. wilsoniana Schneid.; Zelkova serrata (Thunb.) Mak.; Z. carpinifolia (Pall.) K. Koch.; Z. schneideriana Hand.-Mazz,; Z. sinica C.K. Schneid.