Journal of Agricultural Science; Vol. 13, No. 10; 2021 ISSN 1916-9752 E-ISSN 1916-9760 Published by Canadian Center of Science and Education 96 Reproduction of Ooencyrtus submetallicus (Hymenoptera: Encyrtidae) and Trissolcus sp. aff. urichi (Hymenoptera: Scelionidae) in Eggs of Nezara viridula (Hemiptera: Pentatomidae) of Different Ages Eduardo Carvalho Faca 1 , Fabrício Fagundes Pereira 1 , Winnie Cezario Fernandes 1 , Ivana Fernandes da Silva 1 , Valmir Antônio Costa 2 & Ana Paula Gonçalves da Silva Wengrat 3 1 Programa de Pós-graduação de Entomologia e Conservação da Biodiversidade, Universidade Federal da Grande Dourados (UFGD), Dourados, Mato Grosso do Sul, Brazil 2 Instituto Biológico, Agência Paulista de Tecnologia dos Agronegócios, Secretaria de Agricultura e Abastecimento, Campinas, São Paulo, Brazil 3 Departamento de Entomologia e Acarologia, Universidade de São Paulo (USP)/Escola Superior de Agricultura “Luiz de Queiroz” (ESALQ), Piracicaba, São Paulo, Brazil Correspondence: Eduardo Carvalho Faca, Programa de Pós-graduação em Entomologia e Conservação da Biodiversidade, Universidade Federal da Grande Dourados, Dourados, Mato Grosso do Sul, Brazil. Tel: 55-679-8171-6491. E-mail: eduardofaca@gmail.com Received: July 23, 2021 Accepted: August 20, 2021 Online Published: September 15, 2021 doi:10.5539/jas.v13n10p96 URL: https://doi.org/10.5539/jas.v13n10p96 Abstract The study of the interaction between parasitoid and host, especially the age of these organisms, is an important step towards the implementation of biological control programs. Therefore, we investigated the performance of Ooencyrtus submetallicus (Hymenoptera: Encyrtidae) and Trissolcus sp. aff. urichi (Hymenoptera: Scelionidae) parasitizing eggs of Nezara viridula (Hemiptera: Pentatomidae), considering different ages of the parasitoids and the host. We performed four laboratory bioassays: two using females of O. submetallicus and Trissolcus sp. aff. urichi at 24, 48, 72, 96, 120, or 144 hours of age exposed to parasitism in N. viridula eggs (24 h) and two trials with N. viridula eggs at 24, 48, 72, 96, 120, or 144 hours exposed to the parasitism of O. submetallicus and Trissolcus sp. aff. urichi (24 h). We evaluated the percentage of parasitism and emergence, life cycle length, progeny, sex ratio, and the longevity of the parasitoids. The parasitism of O. submetallicus in N. viridula eggs was influenced by the age of the parasitoid, 120 hours being the minimum to obtain better parasitism. From this age on, there is interference in the longevity of the progeny. Trisolcus sp. aff. urichi, at all ages, parasitized N. viridula eggs relatively well, but with almost no emergence of the parasitized eggs. Females of O. submetallicus parasitized and developed in eggs of N. viridula of all ages. Females of Trissolcus sp. aff. urichi parasitized their host, but there was barely any emergence. These pieces of information regarding the breeding methodology contribute to the implementation of new protocols for the multiplication of these parasitoids in the laboratory, and later, their release in the field. Keywords: biological control, host-parasitoid interaction, breeding methodology, egg parasitoid, green stink bug 1. Introduction Biological control is an environmentally friendly and affordable management alternative, adopted to reduce insect populations considered pests for their natural enemies (Parra et al., 2002). In addition, this type of control is used to minimize excessive applications of synthetic insecticides, being a viable tool when associated with other strategies adopted by Integrated Pest Management (IPM) (Parra, 2014; Van Lenteren et al., 2018). For the success of a biological control program, studies involving the interaction between the natural enemy and its host are needed, in order to understand the biology of these organisms and then adopt them as biological control agents (Parra & Zucchi, 2004; Siqueira et al., 2012). Several egg parasitoids have been reported, studied, and used as biological control agents (Crouzel & Saini, 1981; Corrêa-Ferreira & Moscardi, 1996; Queiroz et al., 2018; Martel et al., 2019; Stahl et al., 2019; Zerbino & Panizzi, 2019; Scaccini et al., 2020).