Lethal and Sublethal Effects of Insecticides on the Egg Parasitoid Telenomus podisi (Hymenoptera: Platygastridae).
Insecticide use remains controversial, and subjected to increasing environmental and health concerns, even when recent insecticide groups are considered. Neonicotinoids and even bioinsecticides are in the forefront of discussions regarding their nontarget safety. The ubiquitous focus on the lethal effects of insecticides on nontarget species has been expanding to sublethal effects, as sublethal exposure extends for a longer time and affects a broader range of (nontarget) species. Here we explored the lethal and sublethal effects of a lambda-cyhalothrin + thiamethoxan mixture, the neonicotinoid imidacloprid, and the bioinsecticide azadirachtin on the egg parasitoid Telenomus podisi Ashmead, an important parasitoid of stink bug Euschistus heros (F.), a key soybean pest in neotropical America. Contact with dry insecticide residue on glass surface and (parasitized and healthy) host egg immersion exposure bioassays were performed, assessing their acute lethal effects, and their potential sublethal impairment of parasitism, adult emergence, and fertility of the egg parasitoid. Both imidacloprid and the insecticide mixture exhibited high acute lethal activity toward the parasitoid under contact with dry insecticide residue. These insecticides compromised parasitism and wasp emergence when exposure took place before parasitism. In contrast, azadirachtin did not affect adult survival. However, this bioinsecticide compromised parasitism and progeny production, impairing the female parasitoid reproductive potential. Our results indicate strong negative effects of imidacloprid, and specially of the mixture lambda-cyhalthrin + thiamethoxan. However, even azadirachtin, which exhibited low acute lethality, exhibited significant negative sublethal effects on parasitism and population growth of egg parasitoid, cautioning against their use and the need of semifield and field assessments to confirm such an impact.
Department of Agronomy, Universidade do Estado do Mato Grosso, Tangará da Serra, MT 78300-000, Brazil (leonardo1311@gmail.com; alebut@unemat.br; monica@unemat.br), leonardo1311@gmail.com.
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LM
Turchen
Department of Zoology, Universidade Federal do Paraná, Curitiba, PR 81531-980, Brazil (vanessa.golin@yahoo.com.br), and.
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V
Golin
Department of Agronomy, Universidade do Estado do Mato Grosso, Tangará da Serra, MT 78300-000, Brazil (leonardo1311@gmail.com; alebut@unemat.br; monica@unemat.br).
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AR
Butnariu
Department of Entomology, Universidade Federal de Viçosa, Viçosa, MG 36570-000, Brazil (guedes@ufv.br).
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Guedes
Department of Agronomy, Universidade do Estado do Mato Grosso, Tangará da Serra, MT 78300-000, Brazil (leonardo1311@gmail.com; alebut@unemat.br; monica@unemat.br).
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MJ
Pereira
D000818:Animals; D005260:Female; D020062:Heteroptera / Q000187:drug effects*; D006790:Host-Parasite Interactions / Q000187:drug effects*; D007093:Imidazoles / Q000633:toxicity; D007306:Insecticides / Q000633:toxicity*; D036701:Limonins / Q000633:toxicity; D000073943:Neonicotinoids; D009570:Nitriles / Q000633:toxicity; D009574:Nitro Compounds / Q000633:toxicity; D010078:Oxazines / Q000633:toxicity; D011722:Pyrethrins / Q000633:toxicity; D000077922:Thiamethoxam; D013844:Thiazoles / Q000633:toxicity; D014863:Wasps / Q000187:drug effects*
D007093:Imidazoles; D007306:Insecticides; D036701:Limonins; D000073943:Neonicotinoids; D009570:Nitriles; D009574:Nitro Compounds; D010078:Oxazines; D011722:Pyrethrins; D013844:Thiazoles; C082359:imidacloprid; D000077922:Thiamethoxam; C010329:azadirachtin; C037304:cyhalothrin
azadirachtin; biological control; ecotoxicology; neonicotinoid; selectivity