Preference of temperate Chinese elms (Ulmus spp.) for the adult Japanese beetle (Coleoptera: Scarabaeidae)

Trees of newly acquired Ulmus species originating from the temperate regions of China and growing at The Morton Arboretum, Lisle, IL, were evaluated in no-choice and multiple-choice laboratory bioassays and cage-studies for feeding preference for adults of the Japanese beetle, Popillia japonica Newman. Ulmus lanceaefolia, U. prunifolia, U. pseudopropinqua, and U. taihangshanensis were less preferred for feeding by adult Japanese beetles. No-choice, multiple-choice, and cage feeding studies revealed that Ulmus wallichiana was moderately preferred, and U. procera and U. americana were highly preferred for feeding. Dry fecal pellet weights were strongly correlated with the percent of leaf tissue removed. Feeding preference in the multiple-choice study was strongly correlated with feeding preference in the cage study and in the no-choice study. Likewise, adult feeding preference in the cage study was strongly correlated with preference in the multiple-choice and no-choice studies. The less preferred species of U. lanceafolia, U. prunifolia, U. pseudopropinqua, and U. taihangshanensis show promise for future elm breeding programs.