Benefits and risks of using native parasitoids for augmentative biological control of the invasive pest Halyomorpha halys in Europe

The brown marmorated stink bug, Halyomorpha halys, is an Asian agricultural pest that has invaded both the American continent and Europe. In its native range, H. halys populations are well regulated by natural enemies, with Trissolcus japonicus being the most abundant species. In Europe, the egg parasitoid Anastatus bifasciatus is the most common species parasitizing H. halys eggs. In this PhD thesis I evaluated its potential for augmentative biological control against H. halys in Europe. Investigations on the life history of A. bifasciatus are described in chapter 2. In chapter 3, the host range of A. bifasciatus was examined. Interspecific interactions with another potential European biological control agent of H. halys, Ooencyrtus telenomicida, were evaluated in chapter 4. Experimental releases of A. bifasciatus were conducted over three years in Swiss and Italian fruit orchards, described in chapter 5. The development and testing of a PCR-based screening tool for Anastatus species is addressed in chapter 6. In 2017 and 2018, the first adventive populations of T. japonicus in Europe could be recorded in chapter 7.