Psyllids are a serious pests of pears cultivated in temperate and subtropical regions. Pear psyllids are a member of the large genus Cacopsylla (Psyllidae: Psyllinae). Among the 28 psyllid species that infect pear trees, Cacopsylla chinensis (Yang and Li, 1981) is considered the most harmful. Recently, we found new pear psyllid pest affected Korean pear (Pyrus pyrifolia var. culta) orchards. The psyllid is morphologically identical to C. chinensis and is herein reported as a new record.
In this study, we conducted DNA sequence analysis of the mitochondrial cytochrome oxidase I-leucine tRNA-cytochrome oxidase II (COI-tRNALeu-COII) and 16S rDNA regions to demonstrate the phylogenetic relationships among C. chinensis from pear orchards in Korea, and those recorded from China, Taiwan and Japan. The sequence of the COI-tRNALeu-COII and 16s rDNA regions were equivalent from Korea. Comparison of nucleotide sequences and phylogenetic analysis differentiated Korean psyllids from the Chinese and Taiwanese C. chinensis, but Korean and Japanese psyllids were closely related. The results suggest that Korean and Japanese C. chinensis are genetically homologous. It is presumable that these individuals descended from a single colony that was probably introduced recently.

• Seunghwan Lee(Laboratory of Insect Biosystematics, Department of Agricultural Biotechnology, Seoul National University, Research Institute of Agriculture and Life Sciences, Seoul National University)
• Geonho Cho(Laboratory of Insect Biosystematics, Department of Agricultural Biotechnology, Seoul National University)