The box tree moth (BTM, Cydalima perspectalis Walker) is a pest that infests various plants within the Buxus genus. Although a specific parasitoid wasp species associated with the BTM has been observed in the Republic of Korea, no research on this species has been published. Here we describe the fundamental biological and morphological characteristics of this parasitoid. We placed the wasp under the genus Eriborus (Hymenoptera: Ichneumonidae: Campopleginae). Eriborus sp. parasitizes within the living host body, with one wasp emerging from each host. The parasitism rate in collected BTM populations was 33.1%. The emergence rate was 87.1%, with all emerging adults being females, resulting in a sex ratio of 0. The pupal period averaged 9.5 days, and the adult lifespan averaged 10.5 days. Eriborus sp. parasitized BTM larvae from the first to the fourth instar and reproduced by parthenogenesis. Eriborus sp. exhibited morphological differences compared with previously reported Eriborus species in Korea, particularly in the length of the ovipositor sheath. In addition, the proportion of the highest similarity in nucleotide sequences of mitochondrial cytochrome oxidase I DNA was only 94.53%, rendering species identification using GenBank’s mt cytochrome c oxidase 1 DNA sequences unfeasible. These data suggest Eriborus sp. could be used as a biological control agent for managing BTM infestations.

The genus Eriborus which is a small-sized campoplegine genus was firstly described by Föster in 1869 based on Campoplex perfidus. Members of this genus included 52 species in the world. Among them, 11 species are distributed in Eastern Palaearctic region, and only two species, E. molestae (Uchida, 1933) and E. terebrans (Gravenhorst, 1829) have been recorded in Korea(Yu et al., 2005). Most species of this genus are specialized parasitoids of 17 lepidopteran families, Cerambycidae(Coleoptera) and Tenthredinidae(Hymenoptera), and more particularly attack most of Noctuidae and Pyralidae(Lepidoptera) larvae as koinobiont endoparasitoids. This genus is easily distinguished from other campoplegine genera by the combination of the following characters: Carinae of propodeum usually strong, areola longer than wide; propodeal spiracles circular or short elliptic; fore wings without areolet; thyridium subcircular or longitudinally elliptic. In this study, we found two newly recorded species, Eriborus vulgaris (Morley, 1913) and Eriborus sinicus (Holmgren, 1868) from Korea. A revised key to the species of Korean Eriborus Föster, redescriptions and photographs of diagnostic characters are provided.