Predation and Parasitism of Halyomorpha halys (Hemiptera: Pentatomidae) Eggs in Minnesota

The brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), has spread across North America and is causing serious economic damages. Current management of this pest is based primarily on use of insecticides, which can disrupt integrated pest management programs. Alternatively, biological control is a more benign management tactic. This study provides the first examination of potential impact of parasitoids and predators of pentatomid eggs in Minnesota. Over 2 yr, 10,074 fresh and 9,870 frozen H. halys eggs were deployed in two forest and two soybean habitats in St. Paul, Minnesota from June to August. Our results demonstrate that rates of parasitism and predation were low, accounting for only 0.4 and 3.7%, respectively, across years, habitats, and egg states. In general, the parasitoid Telenomus podisi Ashmead (Hymenoptera: Scelionidae), had higher impacts on H. halys eggs in soybean, and generalist predators were more prevalent in forest habitats. Overall, predation was higher on fresh versus frozen eggs, and parasitism was not consistent across egg states. Although the rates of H. halys mortality due to natural enemies were low, results of our study may be conservative estimates of their true impact. Also, sentinel egg mass surveys should account for undeveloped parasitoids to better quantify H. halys egg mortality by native parasitoids. Alternative management tactics, such as the introduction of Trissolcus japonicus (Ashmead) (Hymenoptera: Scelionidae), could be considered to improve biological control of H. halys. Our findings serve as the foundation for future work on biological control of this pest and other pentatomids.