We report the first detection of Trissolcus mitsukurii in France. More than 1860 sentinel egg masses of Halyomorpha halys (BMSB) were exposed in the field during the 2018–2020 period, and 12 specimens of T. mitsukurii emerged from one egg mass. Their taxonomic identification was confirmed both by morphological and molecular analysis. Trissolcus mitsukurii, similar to T. japonicus, is an egg parasitoid of BMSB in its area of origin in Asia, and both species are considered to be candidates for a classical biological control strategy against BMSB. Trissolcus mitsukurii was previously recorded in Italy where it is well established and widespread, and this may be the source of the French population. Possible permanent establishment and dispersion of T. mitsukurii in France should be monitored with emphasis on its potential effect on BMSB populations.

A parasitoid wasp,Gryon aetheriumTalamas (Hymenoptera, Scelionidae), was reared from eggs of the invasive stink bugBagrada hilaris(Burmeister) (Hemiptera, Pentatomidae) in Chile. The identification ofG. aetherium, which is under study as a biological control agent, was made with morphological and molecular data in the context of a recent taxonomic treatment of this species. The presence of an adventive population ofG. aetheriumin South America has implications for biological control ofB. hilarisin Chile, and other countries on the continent, where this stink bug may become a pest.

In recent years, the collection of eggs of stink bugs (Pentatomidae) has intensified because of the attention given to egg parasitoids in classical biological control strategies against Halyomorpha halys (Stål) in Europe. Several specimens belonging to the genus Telenomus Haliday emerged from field-collected pentatomid eggs. Taxonomic knowledge to date has not been sufficient to enable the research community to identify these specimens to species level. Three species of scelionid wasps (Scelionidae) associated with Pentatomidae, Telenomus gifuensis Ashmead, Telenomus truncatus (Nees von Esenbeck) and Telenomus turesis Walker, have been characterized on a morphological basis. A COI barcode analysis confirmed the genetic distance between the latter two species. An identification key to the three Telenomus species occurring in the Palearctic region associated with stink bugs is provided. Telenomus heydeni Mayr is here considered conspecific with Telenomus truncatus (Nees von Esenbeck).

We report the first detection of Trissolcus japonicus in southwestern France. A total of almost 3000 sentinel and 700 field-laid egg masses of Halyomorpha halys were exposed or collected in the administrative region of Nouvelle-Aquitaine in 2022 and 2023. A total of 12 and 44 specimens of T. japonicus emerged from one and two egg masses in 2022 and 2023, respectively. Morphologic analysis confirmed the identification of this egg parasitoid, while molecular analysis of COI matched the haplotype of the French population to the population of T. japonicus released in Italy. Trissolcus japonicus may have arrived in Nouvelle-Aquitaine from introduction pathways similary to T. mitsukurii, detected in 2020, although these pathways cannot be clearly defined. The co-occurrence of these two major parasitoids of BMSB should now be surveyed as possible competition can arise. In the frame of the biological control program currently running in France against BMSB, the use of one or two parasitoid species is also considered.

Stink bugs (Hemiptera Pentatomidae) are major agricultural pests worldwide, including both native and invasive species. In France, for instance, Halyomorpha halys has rapidly expanded its range, affecting key crops such as hazelnuts, apples, and vegetables. Meanwhile, several native, polyphagous species — Nezara viridula , Palomena prasina and, to a lesser extent, Graphosoma italicum — are re-emerging and impacting diverse crops because of changes in agricultural practices and climatic conditions. Egg parasitoids represent promising biological control agents for these pests, be it through conservation, augmentation or introduction biological control. However, their actual potential is not precisely documented due to a lack of ambitious surveys and possible taxonomic issues. This study aims to address this gap by compiling results obtained from various of egg parasitism surveys of Pentatomidae in France and implementing a large-scale DNA Barcoding approach (2000 individuals) for the emerged parasitoids. Our results indicate a high diversity of egg parasitoids, and detected some taxonomic issues and molecular inconsistencies that warrant further study. Among the three families of egg parasitoids recovered (Encyrtidae, Eupelmide, and Scelionidae), Scelionidae was the most abundant and diverse with nine species of Trissolcus (including the two adventive species, Tr. japonicus and Tr. mitsukurii ) and four Telenomus species (including two unidentified to species). Scelionidae dominated the parasitoid assemblages associated with most of the Pentatomidae host species, except for H. halys for which the eupelmid Anastatus bifasciatus was the most common species. Key Message: Egg parasitoids assemblages associated with stink bug pests in France remain incompletely documented at the national scale. We combined field surveys with large-scale COI barcoding of ∼2,000 parasitoids. Scelionidae dominate: 9 Trissolcus and 4 Telenoms species on most Pentatomidae. Anastatus bifasciatus (Eupelmidae) prevails on invasive Halyomorpha halys . Host-specific communities should guide egg-parasitoid choice for biocontrol.