Assessment of non‐target toxicity of insecticides on Ganaspis brasiliensis (Ihering) in laboratory and field conditions

• Published in: Pest management science Vol. 80; no. 10; pp. 5421 - 5431
• Main Authors: Fellin, Lorenzo, Dal Zotto, Giovanni, Lisi, Fabrizio, Chiesa, Serena Giorgia, Saddi, Alberto, Fusillo, Matteo, Anfora, Gianfranco, Biondi, Antonio, Mori, Nicola, Rossi Stacconi, Marco Valerio
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.10.2024; Wiley Subscription Services, Inc
• Subjects: Agricultural practices; Bioassays; Biological control; Biological effects; Control programs; Cyantraniliprole; Cyhalothrin; Deltamethrin; Drosophila suzukii; Fruit flies; Ganaspis brasiliensis; Insecticides; Insects; Integrated pest management; IPM; Mortality; Organophosphates; Pest control; Pesticides; Pests; Pyrethroids; Spinosad; Sublethal effects; Topical application; Toxicity; Toxicity testing; sublethal effects; biological control; Spinosad; Drosophila suzukii; Cyantraniliprole; IPM
• ISSN: 1526-498X; 1526-4998; 1526-4998
• DOI: 10.1002/ps.8271

Background G1 strain Ganaspis brasiliensis (Ihering) has been recently released in both Europe and America as a biological control agent of the spotted wing drosophila, Drosophila suzukii (Matsumura). In initial phases of classical biological control programs, it becomes imperative to evaluate the susceptibility of parasitoids to insecticides, to identify the best alternatives to adopt in an integrated pest management and organic perspective. In this study, we evaluated lethal and sublethal effects of topical application of five different insecticides classes: neonicotinoids, diamides, pyrethroids, organophosphates and spinosyns. Additionally, we tested residual toxicity in field trials in vineyards and sweet cherry orchards. Results Adult wasps' susceptibility to different insecticides' classes were consistent between laboratory and field. Spinosad exhibited the highest toxicity, with a median lethal concentration (LC50) of 0.00372 of the maximum field dose, and the highest knock‐down effect in field trials, causing 92.5 ± 5% of mortality at T0. λ‐cyhalothrin showed sublethal effects on both male and female insects' longevity when applied at LC30. In field trials, deltamethrin showed the highest persistence, causing significant parasitoid mortality up to 14 days after treatment. Conversely, cyantraniliprole was the least toxic active ingredient according to both topical and residual bioassays, even though its residues caused mortality up to 7 days after the treatment in the field. Conclusion Our results indicate that spinosad and λ‐cyhalothrin are highly toxic to G. brasiliensis, making them incompatible with classical biological control programs. Cyantraniliprole exhibited lower toxicity, and may be considered a selective pesticide for the integrated management of D. suzukii. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. Spinosad was the most toxic active ingredient, in both laboratory bioassays and field trials. Cyantraniliprole resulted as the least toxic and selective one, but showed sublethal effects on longevity at LC30.