First record and integrative analysis of the invasive aphid Cinara pilicornis in South Korea

This study presents the first record of the spruce shoot aphid, Cinara pilicornis (Hartig, 1841) (Hemiptera: Aphididae: Lachninae), in South Korea. Native to Europe, C. pilicornis has expanded its distribution globally and is recognized as a significant quarantine pest in South Korea, posing substantial ecological and economic risks to native spruce trees and forestry ecosystems. Through detailed morphological and molecular analyses, including scanning electron microscopy (SEM) and mitochondrial COI gene sequencing, the identity of C. pilicornis was confirmed. Phylogenetic analyses (BI and NJ) and species delimitation methods (ABGD, ASAP, and bPTP) further validated the species classification, with all South Korean populations belonging to haplotype 1 a putative ancestral haplotype widely distributed across other regions. Population analyses revealed limited genetic diversity in South Korea, suggesting a recent introduction. Climatic niche modeling indicated that C. pilicornis has the potential to establish populations in temperate and subtropical regions, including Europe, North America, coastal South America, and East Asia. Observations of colony behavior on Picea abies revealed high honeydew production and the formation of black sooty mold, causing visible damage to host plants. This study underscores the importance of strengthening quarantine measures and monitoring native spruce trees in national parks to mitigate the spread and impact of this invasive pest. Effective management strategies are essential to prevent further ecological disruption and economic losses caused by C. pilicornis.