Biological control of sentinel egg masses of the exotic invasive stink bug Halyomorpha halys (Stål) in Mid-Atlantic USA ornamental landscapes

• Sentinel egg masses were placed in plots comprised of native or exotic plants.
• Parasitism and predation rates were not affected by plot type or plant genus.
• Parasitism rates were higher in adjacent wooded sites than in experimental plots.
• Seven native and one exotic parasitoid species attacked sentinel egg masses.
• Parasitism and predation rates in experimental plots and wooded sites were low.

Biological invasions have far reaching effects on native plant and arthropod communities. This study evaluated the effect of natural enemies on eggs of the exotic invasive brown marmorated stink bug Halyomorpha halys (Stål) in experimental plots comprising species pairs of 16 ornamental trees and shrub genera from either Eurasia or North America and in wooded areas adjacent to the plots. Sentinel egg masses were placed on leaves of Acer, Cercis, Hydrangea, and Prunus in the plots and in seven genera of trees and shrubs in adjacent woods. Overall, rates of parasitism and predation in experimental plots were low, accounting for only 3.8% and 4.4% of egg mortality, respectively. There were no significant differences in parasitism and predation rates between native or exotic plots or between plants of different genera. In 2015, predation was significantly higher in the experimental plots than in the wooded sites, but parasitism was significantly higher in the wooded sites. In the experimental plots, seven native and one exotic parasitoid species attacked sentinel egg masses. Six native parasitoid species attacked sentinel egg masses in the wooded sites. Parasitoids in the genus Trissolcus were more likely to attack egg masses in exotic plots than in native plots. There is no evidence that native natural enemies attacking eggs of the exotic BMSB were more prevalent in landscapes with native ornamental trees and shrubs than those with exotic trees and shrubs.

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