Parasitization of H. halys Stål (Heteroptera: Pentatomidae) by Trissolcus japonicus (Ashmead) (Hymenoptera: Scelionidae) and other parasitoids in the Lake Constance region (Germany)

Abstract: The parasitism of egg masses from Halyomorpha halys Stål (Heteroptera:
Pentatomidae) was assessed in 2021 in the South German Region of Lake Constance. In total
366 egg masses (in total 8749 eggs from naturally laid eggs and eggs obtained from laboratory rearing) were evaluated for parasitism and predation in the wild. The dominant parasitoid was Trissolcus japonicus (Ashmead) (Hymenoptera: Scelionidae). As of our current knowledge, this is the first conclusive proof of the species presence in this region. Overall, four other parasitoids were detected in the eggs of H. halys. Egg masses collected in the wild showed a parasitization rate of about 25 %. Predation of egg masses was also assessed and was around 34 %.