Ongoing invasion and first parasitoid record of the North American leaf-mining moth Chysaster ostensackenella (Lepidoptera: Gracillariidae) in Primorsky Territory (Russia)

The North American leaf-mining moth Chrysaster ostensackenella (Fitch, 1859) (Lepidoptera: Gracillariidae) is an invasive species newly documented in Russia in 2022 based on our findings in Primorsky Territory. The article provides data on its biology and distribution in the southern part of the region in 2023. A survey of Robinia pseudoacacia (a host plant) carried out in 12 distant settlements revealed widespread spread of Ch. ostensackenella: from the town of Spassk-Dalniy (44°36′N, 132°49′E) on the north to the village of Khasan (42°25′N, 130°38′E) on the south. Significant plant damage (>50% of leaves with the mines) was documented in the city of Artem and the village of Sinyi Gai, moderate (>25%) in Khasan, Bolshoi Kamen and Ussuriysk, and low damage (<10%) in other six settlements. Parasitism was recorded in two localities (Khasan and Slavyanka), reaching 22%. Altogether, six parasitoid adults (five females and one male) of Achrysocharoides chrysasteris Kamijo, 1990 (Hymenoptera: Eulophidae) were reared from the moth pupae. This East Asian parasitoid is a novel record for Russia, and its trophic association with the North American moth is a new to science. Diagnoses of the parasitoid genus and species are given, and the species male is newly described. Additionally, the illustrations of male and female of A. chrysasteris are provided.