Unraveling the compatibility of symbiotic control antimicrobial substances with Trissolcus japonicus in the integrated pest management of Halyomorpha halys

Within the scope of integrated management of brown marmorated stink bug, Halyomorpha halys, the compatibility of symbiotic control with other strategies must be evaluated to promote biodiversity conservation. This study aimed to assess the impact of antimicrobial substances, useful in symbiotic control of H. halys, on the egg parasitoid Trissolcus japonicus through the treatment of egg masses with fungicides (copper hydroxide, sulfur, sweet orange essential oil) and plant biostimulants (flavonoids and chestnut tannin extract), compared with one disinfectant for civil and industrial use (sodium hypochlorite/sodium hydrate/tetraborate decahydrate). Two tests were conducted: one involved exposing egg masses to T. japonicus, followed by treatment post-parasitism for a subset, and treatment after seven days post-parasitism for another subset to evaluate short/long-term effects based on treatment timing variation. Additionally, a choice test between treated and untreated egg masses was conducted to evaluate T. japonicus oviposition preference. Our results showed that all substances did not impact the emergence of parasitoids at both the treatment times, as well as on preference among treatments, choosing indifferently between all paired egg masses. The impact of these formulations should be further studied to assess their effect in the open field and confirm their sustainable use to manage H. halys proliferation.