Abstract
Nine recently developed simple and complex Asian hybrids with Ulmus davidiana, U. japonica, U. parvifolia, U. pumila, U. szechuanica and/or U. wilsoniana parentage were evaluated in no-choice laboratory bioassays for their suitability for the adult elm leaf beetle, Xanthogaleruca luteola (Müller). Suitability of each biotype was defined by the mean percentage of leaf tissue removed, the mean percentage of females ovipositing, and the mean number of eggs laid per female. Adult female beetles laid significantly more eggs on U. pumila (control) and the complex hybrid U. ‘Morton Red Tip’-Danada Charm™ indicating their greater suitability for ELB. The least suitable single and complex hybrids for adult elm leaf beetles as indicated by feeding and reproduction were U. davidiana x U. ‘ Morton’ -Accolade™ and U. szechuanica x U. japonica. Females feeding on more suitable elms oviposited 3 days earlier than females feeding on less suitable elms. Adult beetle fecundity was correlated with the length of the preovipositional period but mean percentage of females ovipositing was not correlated with length of the preovipositional period. Adult males and females lived approximately 4 days longer on the more suitable elms than on less suitable elms but adult longevity was not correlated with suitability. The percentage of leaf tissue removed by adult beetles on the different biotypes was correlated with beetle fecundity. Less suitable selections of U. davidiana x U. ‘ Morton’ -Accolade™ and U. szechuanica x U. japonica seem promising for future elm breeding programs.
Feeding and Ovipositional Responses of Adult Elm Leaf Beetle (Coleoptera: Chrysomelidae) to Simple and Complex Asian Elm Hybrid Selections