Halyomorpha halys (Hemiptera: Pentatomidae) trap captures at orchard and nonorchard sites and the influence of uncultivated woody host plants in adjoining woodlots.

The invasive Halyomorpha halys (Hemiptera: Pentatomidae) has threatened Mid-Atlantic tree fruit since 2010. To identify factors underlying observed differences in H. halys pest pressure among individual orchards within a geographically proximate area, a 3-yr study was conducted across 10 apple orchard and 8 nonorchard sites bordered by unmanaged woodlots. At each site, 3 pheromone traps were monitored weekly for H. halys captures from late April to mid-October. Apple injury was assessed at harvest at orchard sites annually, and a survey of woody plants found in woodlots adjacent to all sites was conducted. There were no significant differences in captures between orchard and nonorchard site types, but captures were significantly different among individual orchard sites and among individual nonorchard sites. A significant positive relationship between the amount of stink bug injury on apple at harvest and late season captures was detected at orchard sites in 2018 and 2019. Among woodlots adjacent to all sites, a significant positive relationship between the proportion of Lonicera spp. and mid- and late-season nymphal captures was identified. Season-long nymphal captures were positively related to the proportion of Lonicera and Elaeagnus and negatively with Sassafras. For adults, captures were negatively related to the proportion of Ailanthus and positively related to the proportion of Fraxinus in the early and mid-season, respectively. Our results indicate that orchard presence was not driving the relative abundance of localized H. halys populations and that differences in relative densities among sites point to other factors, such as abundance of specific uncultivated woody hosts in unmanaged areas.