Identification of Sirex noctilio (Hymenoptera: Siricidae) using a species-specific cytochrome C oxidase subunit I PCR assay.
Sirex noctilio F. (Hymenoptera: Siricidae: Siricinae), a new invasive species in China, is a significant international forestry quarantine pest. Transportation of Sirex in logs, and related wood packing materials, has led to environmental damage and substantial economic loss in many countries around the world. Traditional morphological characteristics are not reliable for identification of the Siricidae family, particularly the larvae. Furthermore, specimens are frequently not in a suitable condition to permit morphological identification. The majority of damage is caused by the larval stage, which excavates galleries that can penetrate to the center of tree boles. Thus, development of a rapid, accurate, and effective molecular identification technique for S. noctilio, which does not require expert morphological knowledge, is necessary. Here, we describe a molecular identification tool based on the mitochondrial DNA gene, cytochrome C oxidase subunit I (COI). We designed a species-specific COI (SS-COI) PCR assay, which allows direct identification of S. noctilio, regardless of developmental stage. Six woodwasp species commonly found in China, Sirex noctilio, Sirex nitobei, Sirex sp., Tremex fuscicornis Fabr., Tremex apicalis Matsumura, and Xeris spectrum, were included in our analyses. Moreover, specimens of S. noctilio from 16 different areas were analyzed. The results demonstrate that our molecular assay is effective and accurate, regardless of developmental stage or type of specimen, consistent with use for quarantine purposes, to prevent the harmful consequences of S. noctilio spread.