Abstract: 【Aim】 This study aims to determine the genetic differences among parasitoids of Lycorma delicatula nymphs from different geographical populations, and to rapidly identify the parasitism of parasitoids on L. delicatula nymphs at the early parasitization stage so as to evaluate the control effects of parasitoids on L. delicatula populations. 【Methods】 The DNA barcoding method was used to sequence COI and 28S rDNA genes of parasitoids of L. delicatula nymphs from different geographical populations. The genetic distances between the parasitoids from different geographical populations were calculated using K2P model, and a phylogenetic tree was constructed using neighbor-joining (NJ) method. The species-specific PCR (SS-PCR) primers were designed to determine whether L. delicatula was parasitized by Dryinus sinicus by amplification of DNA from L. delicatula nymphs using SS-PCR method. Visual assessment method and SS-PCR amplification were used to determine the parasitism rates of the parasitoids on L. delicatula nymphs from different sampling localities. 【Results】 The parasitoids of L. delicatula nymphs were identified as D. sinicus. A total of 16 haplotypes and four haplotypes were detected in COI and 28S rDNA sequences of D. sinicus from different geographical populations, respectively. The genetic distance among D. sinicus from different geographical populations was 0.00691-0.01310. The phylogenetic tree constructed by NJ method showed that D. sinicus samples from different geographical populations were clustered in one branch. SS-PCR primers based on COI sequence could produce good amplification results for both adult and larva of D. sinicus, with the detection threshold of 0.000005 ng/μL DNA. The parasitism rates of D. sinicus on L. delicatula nymphs from different sampling localities were 22.54%-60.00% detected by SS-PCR, significantly higher than those by visual assessment method (5.63%-36.98%). 【Conclusion】 The genetic differences of D. sinicus from different geographical populations are quite low. SS-PCR primers can be used for rapid detection of the early parasitism of L. delicatula by D. sinicus.

Key words: Lycorma delicatula; Dryinus sinicus, geographical population, DNA barcoding, species-specific PCR, parasitism rate