Abstract: 【Aim】To clarify the species of fruit flies that harm citrus and the genetic diversity of different geographical populations and different host populations of the Chinese citrus fruit fly, Bactrocera minax in China. 【Methods】 The mtDNA COI gene was detected to identify the species of fruit flies that harm citrus. The sequences of this mtDNA COI gene fragment (about 505 bp) of citrus fruit flies of 535 individuals from the 28 geographical populations were aligned, and the inter- and intra-species genetic distance was calculated and the phylogenetic tree was constructed by using MEGA software. The genetic diversity of different geographical populations and different host populations of B. minax was analyzed by using DnaSP software. 【Results】 Four species of fruit flies (B. minax, B. dorsalis, B. tsuneonis, and B. ruiliensis) were identified from the infested citrus fruits, with the inter-species genetic distance of 0.0264-0.2410 and the intra-species genetic distance of 0.0000-0.0140. There was no overlap between the intra-and inter-species genetic distances. There was usually only one fruit fly species in single citrus fruit, and very few fruits were harmed by two species of fruit flies (4/43). Among all the fruit fly species, the proportion of B. minax individuals was the highest (90.70%). The genetic diversity of geographical populations of B. minax was high, and there were 17 haplotypes in 28 populations. 【Conclusion】 In the regions surveyed in this study, B. minax is the dominant fruit fly species that damages citrus fruits. There exist a high degree of genetic differentiation and a high risk of proliferation hazard of B. minax. The results of this study are helpful for monitoring and controlling citrus fruit flies.

Key words: Citrus fruit flies, Bactrocera minax, COI gene, phylogenetic development; genetic diversity, citrus