First molecular confirmation of an encyrtid parasitoid emerging from Stemmatomerinx acircula (Hemiptera: Pseudococcidae) infesting Muhlenbergia capillaris in South Carolina

ABSTRACT The muhly grass mealybug Stemmatomerinx acircula Howell & Miller is an emerging pest of Muhlenbergia capillaris (Lam.) Trin. in the southeastern United States, yet no parasitoids have previously been documented from this species. Here, we report the first molecular confirmation of an encyrtid parasitoid emerging from S. acircula collected in South Carolina. Parasitoid adults were obtained from five field samples collected between 2024 and 2025 in Greenville and Columbia. Mitochondrial cytochrome oxidase I, 5′ region ( mt COI5′) sequencing and comparison against the Barcode of Life Data System (BOLD) revealed that all specimens matched BIN ADM2132 (Encyrtidae) with 97.94–99.68% identity to reference sequences from Puerto Rico, California, Mexico, and Canada (Ontario). The parasitoid could not be assigned to a species based on the available morphological and molecular data. This represents the first evidence linking BIN ADM2132 to a mealybug host and the first parasitoid record for S. acircula . These findings expand the known ecological associations of this poorly studied mealybug genus and provide essential molecular resources for future diagnostics, taxonomy, and biological control research.