Abstract: To investigate the genetic diversity of the tea pest C. turpiniae and ascertain the degree of genetic differentiation and provide a theoretical basis for control, genomic DNA of C. turpiniae populations from 11 different geographical regions in Guizhou Province was extracted. It was amplified through PCR and sequenced in order to determine the mtDNA COI gene fragments. Subsequently, analysis of the gene sequence characteristics, haplotypes and genetic diversity, genetic differentiation and gene flow, molecular variation and haplotype phylogenetic analysis was conducted. The results showed that the mtDNA COI gene sequence fragment amplified from C. turpiniae was 658 bp in length, and the sequence showed obvious A+T bias. A total of 10 haplotypes were defined. The total population of C. turpiniae in Guizhou tea gardens had a high level of genetic diversity, high haplotype diversity (Hd=0.800) and high nucleotide diversity (Pi=0.0670). The total population of the eleven geographical populations had a high degree of genetic differentiation (Fst=0.9203) and low level of gene communication (Nm=0.04). The results of the AMOVA analysis showed the majority of the genetic variation in C. turpiniae population due to differences between groups (FCT=0.9129). The comprehensive analysis of neutral test and mismatch distribution showed that the population had not expanded significantly recently. The results of both haplotype phylogenetic analysis and haplotype network clustering showed that C. turpiniae population was clustered into three clades.

Key words: tea newly recorded pest, Crenidorsum turpiniae, mtDNA COI gene, genetic diversity, genetic differentiation