Since the establishment of the brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) in North America and Europe, there has been a large, multi-group effort to characterize the composition and impact of the indigenous community of arthropod natural enemies attacking this invasive pest. In this review, we combine 98 indigenous natural enemy datasets spanning a variety of sampling methods, habitats, and geographic areas. To date, the vast majority of H. halys biological control research has focused on the egg stage, using sentinel egg masses to characterize indigenous parasitoid and predator communities and their contribution to H. halys egg mortality. Although egg parasitism and predation levels by indigenous natural enemies are low (typically <10% each) in most surveys, total egg mortality attributable to natural enemies can be higher (typically between 5 and 25%; up to 83%)—even though these values were likely underestimated in most cases because some mortality due to biological control was not recognized. In North America, where the most data are available, it appears that the relative prevalence of different indigenous parasitoid species varies among habitat types, particularly between crop and non-crop habitats. Predator species responsible for egg mortality are much less commonly identified, but appear to include a wide variety of generalist chewing and sucking predators. To date, studies of natural enemies attacking H. halys nymphs and adults are relatively rare. Based on our review, we identify a number of key research gaps and suggest several directions for future research

Morrison et al.; Frequency, feeding habits … Submitted to: Biological Control 1 2 Frequency, efficiency, and physical characteristics of predation by generalist predators 3 of brown marmorated stink bug (Hemiptera: Pentatomidae) eggs 4 5 2 Morrison et al.; Frequency, feeding habits … Abstract 15The native generalist predator community of Halyomorpha halys, an invasive species in the 16 United States and Europe, has not been well defined to date. The aims of the current study 17 were to determine whether generalist predators that are commonly found in mid-Atlantic 18 orchards and vegetable crops are capable of feeding on H. halys eggs and, if so, to 19 systematically characterize the appearance of feeding damage in order to link it to sentinel 20 egg mass surveys. Over 25 field-collected and commercially available arthropod predator 21 taxa, including adults and immatures, were evaluated as potential predators of H. halys eggs 22

Augmenting generalist predator populations in new apple (Malus domestica Bork) plantings could potentially aid in the establishment of balanced orchard ecosystems that are less susceptible to pest outbreaks. Habitat can be an important factor in retaining predators in a system and can affect predator efficiency. We investigated the potential of increasing a complex of generalist ground-dwelling predators and enhancing biological control in a young ÔGolden DeliciousÕ apple orchard through ground habitat manipulation. We modified the orchard floor with four comparative habitat treatments: (1) detritus-rich compost mulch layer, (2) detritus-free synthetic mulch layer, (3) herbicide-treated vegetation thatch, and (4) bare soil with vegetation hand-removed. Relative abundances of predators and alternative prey in the habitats were measured with pitfall trapping throughout the growing season. Predation was measured using sentinel Cydia pomonella larvae and directly observed in night experiments. Throughout the season, the compost mulch treatment consistently supported significantly greater densities of alternative prey resources for predators, and generalist predators were more abundant in the compost mulch than the other habitats. Predator complex abundance was positively correlated with increasing alternative prey availability in the compost mulch habitat. However, predation of C. pomonella was significantly lower in the compost mulch than in the herbicide-treated thatch habitat. Our study revealed that a prey-rich organic mulch can enhance ground-foraging generalist predators on the orchard floor, but habitat structure may be more important than alternative prey for predation of C. pomonella.