Metcalfa pruinosa is an invasive planthopper that has rapidly spread across South Korea since its first detection in 2005. Long-term suppression is difficult using chemical control alone. This study developed a cocoon-based outdoor release technique for the parasitoid Neodryinus typhlocybae, a major natural enemy of M. pruinosa, and analyzed the seasonal occurrence patterns of both species while evaluating the establishment and parasitism of N. typhlocybae across multiple regions. A rain-shielded release device was designed to facilitate adult emergence and escape, resulting in emergence from more than 75% of the cocoons and the successful escape of 88.9% of the emerged adults. The optimal timing for parasitoid release was identified as mid-to-late June when 4th-instar M. pruinosa nymphs are predominant, while parasitism assessments were best conducted in mid-to-late July during the 5th-instar stage. Between 2024 and 2025, N. typhlocybae cocoons were detected in eight municipalities across five provinces. Notably, cocoon densities reached 8.2 cocoons per 20 leaves in Jangseong in 2024 and 3.2 cocoons in Asan in 2025, clearly demonstrating successful parasitism and overwintering under Korean field conditions. Cocoons also persisted at sites where releases were conducted between 2020 and 2022, without additional releases. No significant relationships were observed between cocoon density and release amount, region, or year, suggesting that host density, microclimate, and other field-level environmental factors have greater influences on parasitism outcomes. This study provides key foundational data supporting the practical implementation of N. typhlocybae for the biological control of M. pruinosa in South Korea.

미국선녀벌레는 2009년 발견이후 현재 131개 시군에 15,730ha가 발생되고 있다. 주로 단감 등 10여종 이상의 작물을 흡즙하여 피해를 준다. 2017년 이탈리아 파도바 대학에서 천적인 선녀벌레집게벌(Neodryinus typhlocybae)을 도입하여 국립농업과학원에서 생태특성 조사, 대량사육 기술개발 및 미국선녀벌레 발생 현장에 방사하고 있다. 선녀벌레집게벌은 미국선녀벌레 어린약충(1~3령)에 기생하면 암컷의 비율이 낮고 수컷은 2화 성 개체가 많아져 생산이 비효율적이다. 본 연구에서 어린약충에 기생할 때 보다 노숙약충에 기생할 경우 3배정 도 암컷생산의 비율이 높아졌고, 월동하고 있는 고치들을 5월 중순 무렵에 20℃의 서늘한 곳에 보관하면 우화시 기를 상온에 놓아둔 것에 비해 10일 이상 늦추는 결과를 얻었다.