Halyomorphahalys(Stål) is a severe agricultural pest that is spreading worldwide from its original distribution in Asia. Egg parasitoids from Asia, which play a key role in the population dynamics ofH.halys, are following its host along global pathways. We present the first records ofTrissolcusmitsukuriiin Europe, and ofTrissolcusjaponicusin Italy. Both discoveries were made in northern Italy, whereH.halysis widely present and has reached extremely high population densities in some areas. Given the availability of their host, the distributions and populations of these exotic egg parasitoids are expected to expand, even in the absence of human intervention.

Pesticides are currently used inside hives, against the honeybee parasite Varroa destructor, producing unwanted contamination effects. To assess the distribution and fate of one of these pesticides (coumaphos), two experimental hives were treated with Perizin (the commercial product containing the active ingredient coumaphos). Samples of honey, wax, pollen, adult bees and larvae taken before treatment and up to 104 days afterwards, showed diffuse contamination. Wood hedges and wax bridges, where the pesticide solution was applied, were analysed as well. A mass balance was calculated, yielding a recovered amount of around 60% just after treatment and 38% 1 month later. Directly contaminated surfaces and wax contained the highest amount of residues. Wax and honey contained different amounts (10, and 0.1% respectively) but both retained residues for long time. Bees ingest most of the product just after treatment, then rapidly eliminate it by metabolism, advection and deposition processes. On the basis of analytical results, a simple model (level I of the fugacity model) was applied to the hive system for different pesticides (coumaphos, malathion, fluvalinate and bromopropylate). Predicted concentrations in wax and honey were compared with those measured, indicating the good predictive capability of this approach.

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The brown marmorated stink bug Halyomorpha halys is an invasive agricultural pest with a worldwide distribution. Classical biological control has been identified as the most promising method to reduce the populations of H. halys. Adventive populations of two candidates for releases, Trissolcus japonicus and Trissolcus mitsukurii, have recently been detected in Europe. To assess their distribution and abundance, a large-scale survey was performed. From May to September 2019, a wide area covering northern Italy and parts of Switzerland was surveyed, highlighting the expanding distribution of both Tr. japonicus and Tr. mitsukurii. Within four years after their first detection in Europe, both species have rapidly spread into all types of habitats where H. halys is present, showing a wide distribution and continuous expansion. Both exotic Trissolcus showed high levels of parasitism rate towards H. halys, while parasitization of non-target species was a rare event. The generalist Anastatus bifasciatus was the predominant native parasitoid of H. halys, while the emergence of native scelionids from H. halys eggs was rarely observed. The presence of the hyperparasitoid Acroclisoides sinicus was also recorded. This study provided fundamental data that supported the development of the first inoculative release program of Tr. japonicus in Europe.

pointed out the need for regular surveys of the susceptibility of V. destructor to the acaricides used.Bioassays that make it possible to study the susceptibility of the mites to pyrethroid and organophosphorous acaricides in the Abstract -The susceptibility of four populations of Varroa destructor to the organophosphorous acaricide coumaphos was studied. The mites were taken from apiaries kept in Lombardy (northern Italy) and tested with a laboratory assay on paraffin wax with known concentrations of coumaphos. The susceptibility of two populations to coumaphos was close to that of susceptible populations, indicated in the literature (LC 50 at 24 hours: 12.6 µg/g); a third population showed a significant, but slight increase in tolerance (LC 50 at 24 hours: 29 µg/g) while the fourth population had a much higher LC 50 (>200 µg/g at 24 hours). In subsequent field trials carried out in the apiary in which the latter population had been sampled, the total average efficacy of two treatments with Perizin ® (the commercial formulation of coumaphos) in colonies without capped brood was 46% (28-88%).coumaphos / Varroa destructor / resistance / bioassay / field trial