Abstract: Wolbachia is a group of intracellular inherited endosymbiontic bacteria infecting a wide range of arthropods and other animals. The infection status of Wolbachia in the migratory pest Cnaphalocrocis medinalis (Guenée) was studied to provide the basis for revealing the reproductive manipulation mechanism and transmission mechanism of Wolbachia in this pest. In this study, specific primers derived from ftsZ and 16S rDNA genes were used to amplify DNA of Wolbachia from 20 populations of C. medinalis in China by polymerase chain reaction (PCR). The results indicated that the C. medinalis populations in China were widely infected by Wolbachia, the highest infection rate was 90% in Wenzhou of Zhejiang and Yangzhou of Jiangsu, and the lowest rate was 40% in Ya’an of Sichuan, Changsha of Hunan and Ninghe of Tianjin. The ftsZ sequences and 16S rDNA sequences were exactly the same in all positive samples from different regions. Wolbachia ftsZ sequences and 16S rDNA sequences in C. medinalis showed 99%-100% and 98%-99% similarity with others belonging to Group B, respectively, suggesting that Wolbachia in C. medinalis belong to Group B. The results show that the infection type of Wolbachia in the C. medinalis is relatively single. This is the first report that Wolbachia is distributed in the populations of C. medinalis in China.

Key words: Cnaphalocrocis medinalis; Wolbachia, ftsZ, 16S rDNA, infection rate, phylogenetic analysis