Host Plant Use by the Invasive <i>Halyomorpha halys</i> (Stål) on Woody Ornamental Trees and Shrubs

<div><p>The brown marmorated stink bug, <i>Halyomorpha halys</i> (Stål) (Hemiptera: Pentatomidae) is an invasive plant-feeding insect native to eastern Asia. This herbivore is highly polyphagous, feeding on and damaging diverse plants, including field crops, vegetables, tree fruits, and ornamentals. Woody ornamental plants provide early- and late-season resources for adults emerging from and returning to overwintering sites, as well as feeding and breeding sites for <i>H</i>. <i>halys</i> throughout the growing season. In this study, we quantify the use of diverse plants by <i>H</i>. <i>halys</i> in two commercial nurseries in Maryland, recording data on the abundance of egg masses, early and late instar nymphs, and adults over a three-year study period. Our specific goals were to provide a quantitative comparison of the use of diverse plant species and cultivated varieties, identify non-hosts that could be used to create landscapes refractory to <i>H</i>. <i>halys</i>, and determine whether the use of plants varied across life stages of <i>H</i>. <i>halys</i> or the taxonomic status of plants. We found broad use of diverse plants in this study, identifying 88 host plants used by all life stages of <i>H</i>. <i>halys</i>. We also highlight the 43 plant taxa that did not support any life stage of <i>H</i>. <i>halys</i> and are thus classified as non-hosts. Interestingly, some of these plants were congeners of highly-used plants, underscoring high intrageneric and intraspecific variation in the use of plants by this polyphagous herbivore. We discuss how the selective planting of non-hosts, especially gymnosperms, may aid in reducing the agricultural and nuisance pest status of this invasive insect.</p>