Ecotoxicology https://doi.org/10.1007/s10646-019-02129-8 Impacts of seven insecticides on Cotesia flavipes (Cameron) (Hymenoptera: Braconidae) Thaís Fagundes Matioli 1 ● Odimar Zanuzo Zanardi 2 ● Pedro Takao Yamamoto 1 Accepted: 16 October 2019 © Springer Science+Business Media, LLC, part of Springer Nature 2019 Abstract The endoparasitoid wasp Cotesia flavipes (Cameron) (Hymenoptera: Braconidae) is inundatively released in Brazilian sugarcane plantations to control the sugarcane borers Diatraea saccharalis (Fabricius) and Diatraea flavipennella (Box) (Lepidoptera: Crambidae). In conjunction with these releases, several synthetic insecticides are used to control the neonate larvae of these pests. We assessed the lethal and transgenerational sublethal effects of seven of these insecticides on C. flavipes. Leaf discs were sprayed at the highest field concentrations of chlorantraniliprole, lambda-cyhalothrin + chlorantraniliprole, chlorfluazuron, triflumuron, lambda-cyhalothrin + thiamethoxam, tebufenozide, and novaluron. Distilled water was used as a negative control. Newly emerged females (24 h old) were placed in Petri dishes containing the treated leaves, and the lethal and transgenerational sublethal effects were assessed for the next two generations. Lambda-cyhalothrin + chlorantraniliprole and lambda-cyhalothrin + thiamethoxam caused 100% mortality of the parasitoid and were highly persistent, causing more than 30% mortality at 30 days after spraying. Chlorantraniliprole, chlorfluazuron, novaluron, and triflumuron did not cause significant mortality compared to the negative control, but did have transgenerational sublethal effects. The length of the tibia of the right posterior leg, used as a growth measurement, was reduced in the progeny (F 1 generation) of exposed female parasitoids. In addition, chlorantraniliprole increased and chlorfluazuron reduced the proportion of females in the F 1 generation, whereas novaluron reduced the proportion of females in the F 2 generation. Overall, only tebufenozide was considered harmless to C. flavipes. The results of this study suggest that lambda-cyhalothrin + chlorantraniliprole and lambda-cyhalothrin + thiamethoxam are harmful to C. flavipes, although field studies are needed to obtain results for actual sugarcane crops. Keywords Diatraea saccharalis ● Larval parasitoid ● Toxicity ● Transgenerational sublethal effects ● Integrated pest management Introduction Brazil is the world’s largest sugarcane producer, with a harvest of 633 million tons on approximately 9 million hectares in 2017/2018 (Conab 2018). In spite of this high production, the incidence of pests is one of the major factors limiting further increases in crop yield (Oliveira et al. 2014). The sugarcane borers Diatraea saccharalis (Fabricius) and Diatraea flavipennella (Box) (Lepidoptera: Crambidae) are key pests of sugarcane, due to their direct and indirect damage, biotic potential, adaptability to different environ- mental conditions, and the abundance of host plants (Joyce et al. 2014; Pavinato et al. 2018; Pinto et al. 2006). Neonate larvae initially feed on the leaf parenchyma, and the second- instar larvae migrate to the base of the plant where they penetrate the stem, opening longitudinal and transverse galleries that block the sap flow, reducing sucrose accu- mulation and crop yield. On young plants, these borers can dry the shoots, which prevents further growth and even- tually kills the plant (Dinardo-Miranda 2008); and they weaken older plant stalks, which may topple in the wind (Trevisan et al. 2016). Because the larvae develop almost completely inside the stem, D. saccharalis has been controlled preferably by * Thaís Fagundes Matioli thaisf.matioli@usp.br 1 Department of Entomology and Acarology, “Luiz de Queiroz” College of Agriculture/University of São Paulo (ESALQ/USP), Piracicaba, São Paulo 13418-900, Brazil 2 Department of Entomology, Fund for Citrus Protection (FUNDECITRUS), Araraquara, São Paulo 14708-040, Brazil 1234567890();,: 1234567890();,: