Simplified rapid differentiation of Liriomyza chinensis Kato (Diptera; Agromyzidae) genotypes A and B using PCR-RFLP.

The stone leek leaf miner Liriomyza chinensis Kato is one of the most important pests of Allium spp. In recent years, a new genotype of L. chinensis, genotype B, has been shown to cause more severe damage to Allium spp. compared with the native genotype A in Japan. Thus, identification of the genotypes is important for establishing L. chinensis control strategies. In this study, we developed a simple and rapid method of genotype identification using PCR-restriction fragment length polymorphism (RFLP). Primers were designed to mitochondria cytochrome oxidase subunit I gene (mtCOI) nucleotide sequences from both genotypes. Genotype A and B were successfully identified using the restriction enzymes PvuI and DdeI, respectively. Using PCR-RFLP, we identified the genotype of L. chinensis samples (n = 108) collected in seven Japanese bunching onion fields in Ibaraki Prefecture, Japan. All individuals were shown to be genotype B, as expected.